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Phylogenetic analyses of the Amphilinidea and Gyrocotylidea : (Cercomeria: Brooks, 1982) Bandoni, Susan Marie 1985

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PHYLOGENETIC ANALYSES OF THE AMPHILINIDEA AND GYROCOTYLIDEA (CERCOMERIA: BROOKS, 1982) by SUSAN MARIE BANDONI B.Sc, The University Of B r i t i s h Columbia, 1983 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE in THE FACULTY OF GRADUATE STUDIES Zoology Department We accept th i s thesis as conforming t^T^he required standard THE UNIVERSITY OF BRITISH COLUMBIA September 1985,^  © Susan Marie Bandoni, 1985(| 9Q In presenting t h i s thesis i n p a r t i a l f u l f i l m e n t of the requirements for an advanced degree at the University of B r i t i s h Columbia, I agree that the Library s h a l l make i t f r e e l y available for reference and study. I further agree that permission for extensive copying of t h i s thesis for scholarly purposes may be granted by the head of my department or by his or her representatives. I t i s understood that copying or publication of t h i s thesis for f i n a n c i a l gain s h a l l not be allowed without my written permission. Department of The University of B r i t i s h Columbia 1956 Main Mall Vancouver, Canada V6T 1Y3 i i A b s t r a c t The a m p h i l i n i d e a n s and g y r o c o t y l i d e a n s are s m a l l groups of monozoic p l a t y h e l m i n t h s p a r a s i t i z i n g f i s h e s and o c c a s i o n a l l y t u r t l e s . They have t r a d i t i o n a l l y been p l a c e d w i t h the c e s t o d e s because they l a c k a g u t . S y s t e m a t i c r e l a t i o n s h i p s of the two groups a r e p o o r l y u n d e r s t o o d . E i g h t s p e c i e s of a m p h i l i n i d e a n s a r e c o n s i d e r e d v a l i d . A p h y l o g e n e t i c a n a l y s i s of 46 c h a r a c t e r s t a t e s c o m p r i s i n g 34 homologous s e r i e s produced a s i n g l e p h y l o g e n e t i c t r e e w i t h a c o n s i s t e n c y index v a l u e of 89%, i n d i c a t i n g a v e r y low degree of homoplasy. The number of genera has been reduced from s i x t o t h r e e , i n an attempt t o c o n s t r u c t a c l a s s i f i c a t i o n which r e f l e c t s the p h y l o g e n e t i c r e l a t i o n s h i p s of the group. The p h y l o g e n e t i c r e l a t i o n s h i p s e x h i b i t a f a i r l y h i g h degree of congruence (70%) w i t h a c u r r e n t l y a c c e p t e d h y p o t h e s i s of p h y l o g e n e t i c r e l a t i o n s h i p of the t e l e o s t s . T h i s i m p l i e s t h a t c o e v o l u t i o n has o c c u r r e d , a l t h o u g h w i t h many p a r a s i t e l o s s e s and e x t i n c t i o n s . An a n a l y s i s of the b i o g e o g r a p h i c d i s t r i b u t i o n of the a m p h i l i n i d e a n s u s i n g t h e methods of v i c a r i a n c e biogeography produced complete or n e a r l y complete congruence of the d i s t r i b u t i o n of a m p h i l i n i d e a n s w i t h hypotheses of a r e a r e l a t i o n s h i p , i n d i c a t i n g t h a t v i c a r i a n c e i s the best e x p l a n a t i o n f o r the b i o g e o g r a p h i c d i s t r i b u t i o n of the group. Ten s p e c i e s of g y r o c o t y l i d e a n s are r e c o g n i z e d , of which seven were examined i n t h i s s t u d y . A p h y l o g e n e t i c a n a l y s i s of 24 c h a r a c t e r s t a t e s c o m p r i s i n g 13 homologous s e r i e s produced two t r e e s of e q u a l l e n g t h . The c o n s i s t e n c y i n d e x f o r each t r e e i s 88%, i n d i c a t i n g a v e r y low degree of homoplasy. The p h y l o g e n e t i c a n a l y s i s of the gyrocotylideans has provided a summary of the current knowledge of the gyrocotylideans which can serve as a framework for further investigations. S l i g h t l y more than half of the observed associations between gyrocotylideans and holocephalans can be attributed to coevolution. Remaining associations can be at t r i b u t e d to colonization, but these represent recolonizations of plesiomorphic hosts. The geographic d i s t r i b u t i o n of gyrocotylideans remains enigmatic, as i t does not appear to r e f l e c t plate movements. It i s suggested that their d i s t r i b u t i o n may be pfe-Pangaean in o r i g i n . The phylogenetic analyses of the amphilinideans and gyrocotylideans have provided corroboration for a hypothesis of rel a t i o n s h i p for the Subphylum Cercomeria. Seven new characters have been i d e n t i f i e d as autapomorphies for the amphilinideans and gyrocotylideans, while an additional seven new characters support the Subclass Cestodaria and the Infrasubclass Cestoidea. Amphilinideans and gyrocotylideans both appear to be r e l i c t groups, but of d i f f e r e n t types. The amphilinideans were probably more widespread and more numerous than they are at present ( i . e . they are geographic and numerical r e l i c t s ) . The gyrocotylideans, on the other hand, appear to have never been diverse or widespread, and are therefore phylogenetic r e l i c t s . iv Table of Contents Abstract i i L i s t of Tables v i L i s t of Figures v i i Acknowledgement x Chapter I INTRODUCTION 1 Chapter II PHYLOGENETIC ANALYSIS OF THE SUPERORDER AMPHILINIDEA POCHE, 1922 7 INTRODUCTION 7 METHODS AND MATERIALS 11 CHARACTER ANALYSIS 14 CHARACTERS NOT INCLUDED IN THE ANALYSIS 25 RESULTS 26 KEY TO THE SPECIES OF THE SUPERORDER AMPHILINIDEA ..42 SPECIES INQUIRENDAE 43 DISCUSSION 4 5 COEVOLUTION OF AMPHILINIDEAN PARASITES AND THEIR HOSTS ...45 BIOGEOGRAPHY 48 Chapter III PHYLOGENETIC ANALYSIS OF THE GYROCOTYLIDEA 54 INTRODUCTION 54 METHODS AND MATERIALS 60 CHARACTER ANALYSIS 62 CHARACTERS NOT INCLUDED IN THE ANALYSIS 69 RESULTS ....70 KEY TO THE SPECIES OF THE INFRASUBCLASS GYROCOTYLIDEA 89 DISCUSSION 90 HOST RELATIONSHIPS 92 BIOGEOGRAPHY 95 Chapter IV GENERAL DISCUSSION 99 RECIPROCAL ILLUMINATION 99 THE BIOLOGY OF RELICT GROUPS 101 V LITERATURE CITED 105 APPENDIX A - 239 APPENDIX B - 242 MATRIX DESCRIBING HOST RELATIONSHIPS AS DERIVED FROM BIGELOW AND SCHROEDER, 1953 243 MATRIX DESCRIBING AREA RELATIONSHIPS FOR GYROCOTYLIDS 243 v i L i s t of T a b l e s I . A m p h i l i n i d c h a r a c t e r m a t r i x 239 I I . T e l e o s t e a n r e l a t i o n s h i p s based on Lauder and Liem, 1982 239 I I I . Area m a t r i x based on C o l b e r t (1981), C r a c r a f t (1972) and G o s l i n e ( 1972) 240 IV. Area cladogram based on B r u s c a (1984) and Thomson (1981 ) 240 V. Area cladogram based on Rosen ( 1978) 240 V I . Area cladogram based on D i e t z and Holden (1971) ...241 V I I . G y r o c o t y l i d c h a r a c t e r m a t r i x 242 V I I I . M a t r i x d e s c r i b i n g h o s t r e l a t i o n s h i p s as d e r i v e d from p a r a s i t e t r e e 242 v i i L i s t of F i g u r e s 1. P h y l o g e n e t i c R e l a t i o n s h i p s of the Cercomeromorphae Bychowsky, 1937 1 1 4 2. P h y l o g e n e t i c r e l a t i o n s h i p s of the C e r c o m e r i a B r o o k s , 1982 1 16 3. Body Shapes of A m p h i l i n i d e a n s 118 4. The s u r f a c e of the tegument of a m p h i l i n i d e a n s 120 5. T e r m i n a l G e n i t a l i a of A m p h i l i n a 122 6. F o r m a t i o n of the a c c e s s o r y s e m i n a l r e c e p t a c l e s 124 7. V a r i a t i o n i n ovary shape i n the a m p h i l i n i d e a n s 126 8. S p a t i a l r e l a t i o n s h i p s of the female g e n i t a l d u c t s of a m p h i l i n i d e a n s 128 9. A m p h i l i n a f o l i a c e a 130 10. A m p h i l i n a j a p o n i c a 132 11. S c h i z o c h o e r u s paraqonopora 135 1 2. S c h i z o c h o e r u s l i q u l o i d e u s 141 1 3 . S c h i z o c h o e r u s j a n i c k i i 1 46 1 4 . S c h i z o c h o e r u s a f r i c a n u s 149 15. G i q a n t o l i n a e l o n q a t a 151 16. G i q a n t o l i n a magna 155 17. H y p o t h e s i s of p h y l o g e n e t i c r e l a t i o n s h i p f o r the A m p h i l i n i d e a 159 18. H o s t s of A m p h i l i n i d e a n s 161 19. P h y l o g e n e t i c r e l a t i o n s h i p s of h o s t s of a m p h i l i n i d e a n s 163 20. P h y l o g e n e t i c r e l a t i o n s h i p s of a m p h i l i n i d e a n s , showing p o s t u l a t e d c o l o n i z a t i o n s 165 21. The b i o g e o g r a p h i c d i s t r i b u t i o n of a m p h i l i n i d e a n p l a t y h e l m i n t h s 167 v i i i 22. Comparison of the p h y l o g e n e t i c r e l a t i o n s h i p s of a m p h i l i n i d e a n s w i t h hypotheses of a r e a r e l a t i o n s h i p .169 23. The f u n n e l of g y r o c o t y l i d s 177 24. The g e n i t a l n o t c h of g y r o c o t y l i d s 179 25. The t e s t e s and u t e r i n e sac 181 26. Tegumental s p i n e s of g y r o c o t y l i d s 183 27. G y r o c o t y l e rugosa 192 28. U t e r i n e c o n f o r m a t i o n of G y r o c o t y l e rugosa 195 29. D i s t r i b u t i o n of v i t e l l a r i a i n G y r o c o t y l e rugosa 197 . 30. G y r o c o t y l e n y b e l i n i 199 31. G y r o c o t y l e maxima 202 32. G y r o c o t y l e p a r v i s p i n o s a 204 33. G y r o c o t y l e c o n f u s a 208 34. G y r o c o t y l e a b y s s i c o l a 210 35. G y r o c o t y l e n i g r o s e t o s a 212 36. G y r o c o t y l e urna 214 37. G y r o c o t y l e major 216 38. G y r o c o t y l e f i m b r i a t a 218 39. Hypotheses of R e l a t i o n s h i p f o r the G y r o c o t y l i d e a ....220 40. Consensus t r e e f o r the G y r o c o t y l i d e a 224 41. The p h y l o g e n e t i c r e l a t i o n s h i p s of g y r o c o t y l i d e a n s , w i t h the b e s t - f i t t i n g host t r a n s f o r m a t i o n s e r i e s mapped on. 226 42. Comparison of the p h y l o g e n e t i c r e l a t i o n s h i p s of g y r o c o t y l i d e a n s w i t h a host phylogeny based on the b e s t -f i t t i n g t r a n s f o r m a t i o n s e r i e s 228 43. Comparison of the p h y l o g e n e t i c r e l a t i o n s h i p s of g y r o c o t y l i d e a n s w i t h a hos t phylogeny based on B i g e l o w and S c h r o e d e r , 1953 ' 230 44. Area c l a d o g r a m showing the g e o g r a p h i c d i s t r i b u t i o n of g y r o c o t y l i d e a n s 232 i x 45. H y p o t h e s i s of p h y l o g e n e t i c r e l a t i o n s h i p f o r the g y r o c o t y l i d s , showing the b e s t f i t t i n g a r e a t r a n s f o r m a t i o n s e r i e s 234 46. H y p o t h e s i s of p h y l o g e n e t i c r e l a t i o n s h i p f o r the g y r o c o t y l i d s , showing the f i t of an a r e a cladogram based on the b e s t - f i t t i n g t r a n s f o r m a t i o n s e r i e s 236 X Acknowledgement I would l i k e t o thank the f o l l o w i n g p e o p l e f o r a r r a n g i n g l o a n s or g i f t s of specimens used i n t h i s s t u d y : Dr. F. R. A l l i s o n ( U n i v e r s i t y of C a n t e r b u r y , New Z e a l a n d ) , Dr. Tor A. Bakke ( Z o o l o g i c a l Museum, U n i v e r s i t y of O s l o ) , Dr. A. G. Chabaud (Museum N a t i o n a l d ' H i s t o i r e N a t u r e l l e , Geneva), Dr. D a v i d I . G i b s o n ( B r i t i s h Museum, N a t u r a l H i s t o r y , London), Dr. G e r h a r d H a r t w i c h ( Z o o l o g i c a l Museum, Humboldt U n i v e r s i t a t , B e r l i n , D.D.R.), Dr. Pat H u t c h i n g s ( A u s t r a l i a n Museum, Sydney), Dr. Shunya Kamegai (Meguro p a r a s i o l o g i c a l Museum, Toky o ) , Dr. Johanne K j e n n e r u d ( Z o o l o g i c a l Meuseum, U n i v e r s i t y of B e r g e n ) , Dr. Eugene K o z l o f f ( U n i v e r s i t y of W ashington),Dr. R a l p h L i c h t e n f e l s (U. S. N a t i o n a l Museum, B e l t s v i l l e ) , Dr. Goran Malmberg ( N a t u r h i s t o r i s k a R i j k s m u s e e t , G o t e b o r g ) , Dr. Mary P r i t c h a r d ( H a r o l d W. Manter L a b o r a t o r y , L i n c o l n , N e b r a s k a ) , Dr. K l a u s Rohde ( U n i v e r s i t y of New E n g l a n d , New South W a l e s ) , and Dr. C l . Vaucher (Museum N a t i o n a l d ' H i s t o i r e N a t u r e l l e , P a r i s ) . I would a l s o l i k e t o thank C h e r y l Macdonald, Pat Shaw, Gordon Haas, Bob C a r v e t h , Dr. H. L. C h i n g , and Dr. C. L i n d s e y ; t h e s e i n d i v i d u a l s p r o v i d e d h e l p f u l comments on v a r i o u s a s p e c t s of t h i s s t u d y . I would e s p e c i a l l y l i k e t o thank R i c h a r d O'Grady and Dr. J . D. M c P h a i l , w i t h whom I spent a c o n s i d e r a b l e amount of time, d i s c u s s i n g t h i s p r o j e c t . I would a l s o l i k e t o thank my s u p e r v i s o r , Dr. D a n i e l R. Brooks f o r s u g g e s t i n g t h i s a r e a of i n v e s t i g a t i o n , and f o r the g u i d a n c e and t r a i n i n g he p r o v i d e d . The diagrams were p r e p a r e d by Maggie Hampong ( c h a p t e r s I and I I ) and Gordon Addie ( c h a p t e r s I I I and I V ) . Gordon Addie a l s o h e l p e d t o c o m p i l e and check the b i b l i o g r a p h y . 1 I . INTRODUCTION T r a d i t i o n a l l y , the p a r a s i t i c p l a t y h e l m i n t h s have been p l a c e d i n two c l a s s e s , the C l a s s Trematoda and the C l a s s C e s t o i d e a , based on the presence or absence of the g u t . The c e s t o d e s have i n t u r n been d i v i d e d i n t o the S u b c l a s s E u c e s t o d a , or t r u e tapeworms, and the S u b c l a s s C e s t o d a r i a , i n c l u d i n g the a m p h i l i n i d e a n s and g y r o c o t y l i d e a n s . The c e s t o d a r i a n s have been c o n s i d e r e d t o be i n t e r m e d i a t e between the trematodes and the c e s t o d e s (see Watson, 1911; M o n t i c e l l i , 1892). Some a u t h o r s (see S t u n k a r d , 1962) have c o n s i d e r e d the a m p h i l i n i d e a n s and g y r o c o t y l i d e a n s t o be a b e r r a n t and of l i t t l e v a l u e i n e l u c i d a t i n g the p h y l o g e n e t i c r e l a t i o n s h i p s of the p a r a s i t i c p l a t y h e l m i n t h s . Others (see L l w e l l y n , 1965; P r i c e , 1967) have suggested t h a t the a m p h i l i n i d e a n s and g y r o c o t y l i d e a n s occupy a c r i t i c a l p o s i t i o n i n the phylogeny of the p l a t y h e l m i n t h s and have s i n g l e d them out f o r s p e c i a l a t t e n t i o n . The S u b c l a s s C e s t o d a r i a was e s t a b l i s h e d by M o n t i c e l l i (1892), based on the absence of the gut and the absence of body se g m e n t a t i o n . The c e s t o d a r i a n s were thus r e c o g n i z e d by the absence of a d e r i v e d t r a i t ( t h e p o l y z o i c body) and by the presence of a d e r i v e d t r a i t which i s not unique ( t h e l o s s of the gut ; see f i g s . 1, 2 ) . The S u b c l a s s C e s t o d a r i a was o r i g i n a l l y c o m p r i s e d of the a m p h i l i n i d e a n s , g y r o c o t y l i d e a n s and c a r y o p h y l l i d s . Lonnberg (1897) d i s c o v e r e d e v i d e n c e of segmentation i n c a r y o p h y l l i d s and c o n c l u d e d t h a t t h e s e p l a t y h e l m i n t h s a r e s e c o n d a r i l y monozoic. The c a r y o p h y l l i d s were a c c o r d i n g l y removed from the S u b c l a s s 2 C e s t o d a r i a by Luhe (1910; i n S o u t h w e l l , 1928). Watson (1911), however, p r e f e r r e d t o c l a s s i f y on the b a s i s of p e r c e i v e d a d a p t i v e l e v e l s r a t h e r than on t h e b a s i s of m o r p h o l o g i c a l h omologies and t h e r e f o r e r e t a i n e d the c a r y o p h y l l i d s w i t h the C e s t o d a r i a . Woodland (1923a) adopted a n o v e l approach t o the c l a s s i f i c a t i o n of the c e s t o d a r i a n s . He e s t a b l i s h e d the Order P a r a l i n i d e a , i n c l u d i n g the g y r o c o t y l i d e a n s and c a r y o p h y l l i d s . The p a r a l i n i d e a n s were r e c o g n i z e d on the b a s i s of the p o s i t i o n of the g e n i t a l a p e r t u r e s , the c o n f o r m a t i o n of the u t e r u s , the p o s i t i o n of the t e s t e s , and the p r e s e n c e of a b i l o b e d ovary and r e t i c u l a t e e x c r e t o r y system. A l l of t h e s e c h a r a c t e r i s t i c s a r e s y m p l e s i o m o r p h i e s ( i . e . they a r e s h a r e d g e n e r a l i z e d c h a r a c t e r i s t i c s not r e s t r i c t e d t o the g y r o c o t y l i d e a n s and c a r y o p h y l l i d s ) , and so cannot be used t o d e l i n e a t e a n a t u r a l t a x o n (see f i g . 1 ) . In many of the more r e c e n t c l a s s i f i c a t i o n s proposed f o r the p a r a s i t i c p l a t y h e l m i n t h s (Bychowsky, 1957; L l e w e l l y n , 1965; P r i c e , 1967; Malmberg, 1974; Brooks et a l . , 1985a), the tapeworms, a m p h i l i n i d s , g y r o c o t y l i d s and monogeneans have been p l a c e d i n the Cercomeromorphae Bychowsky, 1937, based on the p r e s e n c e of hooks on t h e cercomer, o r l a r v a l a d h e s i v e organ (see Brooks e_t a l . , I 9 8 5 a a ) . These f o u r t a x a d i f f e r i n the number of cercomer hooks they p o s s e s s , the monogeneans h a v i n g t e n t o s i x t e e n , the tapeworms h a v i n g s i x , and a m p h i l i n i d s and g y r o c o t y l i d s b o t h h a v i n g t e n (see B r o o k s , 1982; Brooks et a l . , I 9 8 5 a a ) . C a r y o p h y l l i d s have s i x cercomer hooks, as do o t h e r 3 t r u e tapeworms. Some a u t h o r s , p a r t i c u l a r l y t h o s e who do not r e c o g n i z e a r e l a t i o n s h i p t o the monogeneans, (see Fuhrmann, 1931; Joyeux and Baer, 1961) have p l a c e d the a m p h i l i n i d e a n s and g y r o c o t y l i d e a n s t o g e t h e r based on the pr e s e n c e of t e n cercomer hooks. Other a u t h o r s advocate the s e p a r a t i o n of the a m p h i l i n i d s and g y r o c o t y l i d s , e i t h e r p l a c i n g them as s e p a r a t e t a x a of e q u a l rank w i t h the monogeneans and tapeworms ( P r i c e , 1967; Malmberg, 1974; Brooks e_t a l . , I985aa), or p l a c i n g the a m p h i l i n i d s w i t h the c e s t o d e s and the g y r o c o t y l i d s w i t h the monogeneans (Bychowsky, 1957; L l w e l l y n , 1967; see a l s o Van der Land and Templeman, 1968; van der Land and D i e n s k e , 1968; D i e n s k e , 1968). In an e f f o r t t o choose between the t h r e e a l t e r n a t i v e s , i n v e s t i g a t o r s have embarked on a number of c o m p a r a t i v e d e v e l o p m e n t a l , u l t r a s t r u c t u r a l and b i o c h e m i c a l s t u d i e s of a m p h i l i n i d e a n s and g y r o c o t y l i d e a n s . Malmberg (1974) has s t u d i e d the embryology of the e x c r e t o r y system. C o l e (1968) examined the u l t r a s t r u c t u r e of the tegument. Lyons (1966; 1969) a l s o s t u d i e d the u l t r a s t r u c t u r e of t h e tegument as w e l l as the c h e m i c a l c o m p o s i t i o n of the cercomer hooks. U n f o r t u n a t e l y , a l l of thes e s t u d i e s have employed p r i m a r i l y e i t h e r G y r o c o t y l e f i m b r i a t a and Amphi1ina j a p o n i c a or G y r o c o t y l e  urna and Amphi1ina f o l i a c e a , the more common N o r t h American and European s p e c i e s r e s p e c t i v e l y . L i t t l e o r no work o f t h i s k i n d has been done t o date w i t h s p e c i e s from the t r o p i c s o r s o u t h e r n hemisphere. F u r t h e r m o r e , the taxonomic r e l a t i o n s h i p s w i t h i n the two groups a r e s u f f i c i e n t l y u n c e r t a i n as t o make any 4 e x t r a p o l a t i o n of these f i n d i n g s t o the o t h e r s p e c i e s somewhat tenuous. D u b i n i n a (1960) argued t h a t f o u r of the t e n cercomer hooks of a m p h i l i n i d s d i f f e r i n appearance and e m b r y o l o g i c a l o r i g i n . Lyons (1966) demonstrated t h a t the two groups of cercomer hooks of a m p h i l i n i d s d i f f e r i n t h e i r c h e m i c a l c o m p o s i t i o n , the group of s i x b e i n g the same as the hooks of g y r o c o t y l i d s and tapeworms, and the group of f o u r are s i m i l a r (but not i d e n t i c a l ) t o the a n c h o r s of monogeneans. The f i n d i n g s of Lyons (1966) and D u b i n i n a (1960) suggest t h a t the number of cercomer hooks cannot be used t o u n i t e the a m p h i l i n i d e a n s and g y r o c o t y l i d e a n s . As w e l l , some doubt as t o whether a l l a m p h i l i n i d e a n s p e c i e s e x h i b i t two c l a s s e s of hooks has been e x p r e s s e d by Malmbe'rg (1974). The c l a s s i f i c a t i o n of Brooks et a_l. (1985a) r e p r e s e n t s the most p a r s i m o n i o u s arrangement of the c h a r a c t e r s employed i n e a r l i e r c l a s s i f i c a t i o n s of the p l a t y h e l m i n t h s . These a u t h o r s have found a d d i t i o n a l c h a r a c t e r i s t i c s w h i c h support the s e p a r a t i o n of the a m p h i l i n i d e a n s and g y r o c o y l i d e a n s even when the cercomer hooks a r e o m i t t e d from the a n a l y s i s . E x i s t i n g c l a s s i f i c a t i o n s of both groups a r e i n g e n e r a l not based on the e x a m i n a t i o n of specimens of a l l of the d e s c r i b e d s p e c i e s . In a d d i t i o n , the c r i t e r i a f o r c l a s s i f i c a t i o n have not been made c l e a r . T h i s s t u d y t h e r e f o r e r e p r e s e n t s the f i r s t a ttempt t o e l u c i d a t e the p h y l o g e n e t i c r e l a t i o n s h i p s of t h e s e two groups. Ten s p e c i e s of g y r o c o t y l i d e a n s a r e c o n s i d e r e d v a l i d ; a l l a r e p a r a s i t e s of h o l o c e p h a l a n f i s h e s . A m p h i l i n i d e a n 5 p l a t y h e l m i n t h s , of which e i g h t s p e c i e s a r e r e c o g n i z e d , e x h i b i t g r e a t e r d i v e r s i t y i n hos t a s s o c i a t i o n s , p a r a s i t i z i n g a c i p e n s e r i f o r m , o s t e o g l o s s i f o r m , mormyriform, s i l u r i f o r m , p e r c i f o r m and c h e l o n i a n s p e c i e s . A s s o c i a t i o n s between h o s t s and p a r a s i t e s may be the r e s u l t of c o e v o l u t i o n or of c o l o n i z a t i o n . By comparing hypotheses of p h y l o g e n e t i c r e l a t i o n s h i p s f o r h o s t s and p a r a s i t e s , i t i s p o s s i b l e t o o b t a i n an e s t i m a t e of the r e l a t i v e c o n t r i b u t i o n s of the two p r o c e s s e s i n the e v o l u t i o n of a p a r t i c u l a r p a r a s i t e taxon (see Br o o k s , 1979, 1981). The p h y l o g e n e t i c t r e e s o b t a i n e d f o r the a m p h i l i n i d e a n s and g y r o c o t y l i d e a n s have been compared w i t h c l a s s i f i c a t i o n s of the t e l e o s t s and the h o l o c e p h a l a n s r e s p e c t i v e l y i n o r d e r t o determine the e x t e n t of h o s t - p a r a s i t e c o e v o l u t i o n i n these groups. Both the a m p h i l i n i d e a n s and g y r o c o t y l i d e a n s have d i s t r i b u t i o n s which a r e wo r l d w i d e , but h i g h l y l o c a l i z e d . Organisms may become a s s o c i a t e d w i t h g e o l o g i c a l l o c a l i t i e s e i t h e r t h r o u g h d i s p e r s a l or t h r o u g h v i c a r i a n c e ( p a s s i v e h i s t o r i c a l a s s o c i a t i o n ) . Because p l a t y h e l m i n t h s e x h i b i t a low degree of v a g i l i t y , v i c a r i a n c e i s o f t e n a more p l a u s i b l e e x p l a n a t i o n f o r t h e i r g e o g r a p h i c d i s t r i b u t i o n s . Comparison of a h y p o t h e s i s of p h y l o g e n e t i c r e l a t i o n s h i p w i t h knowledge of h i s t o r i c a l g e o l o g y can p r o v i d e i n s i g h t s i n t o the the r o l e of v i c a r i a n c e i n t h e i r e v o l u t i o n . . The h o s t and b i o g e o g r a p h i c d i s t r i b u t i o n s of the a m p h i l i n i d e a n s and g y r o c o t y l i d e a n s have been used t o su p p o r t the n o t i o n t h a t t h e s e t a x a a r e e v o l u t i o n a r y r e l i c t s . The word 6 " r e l i c t " has been a p p l i e d t o a v a r i e t y of h i s t o r i c a l phenomena (see Simpson, 1944). Two p o s s i b i l i t i e s a r e of c o n c e r n h e r e : the g y r o c o t y l i d e a n s and a m p h i l i n i d e a n s may e i t h e r be the remnants of a f o r m e r l y w i d e s p r e a d and s p e c i o s e group, or a l t e r n a t i v e l y they may s i m p l y have undergone v e r y l i t t l e d i f f e r e n t i a t i o n . I n t u i t i v e l y , the s p o t t y d i s t r i b u t i o n of the a m p h i l i n i d s would seem t o be more i n a c c o r d a n c e w i t h the former p o s s i b i l i t y , w h i l e the more u n i f o r m d i s t r i b u t i o n of t h e g y r o c o t y l i d s i s s u g g e s t i v e of the l a t t e r . I t i s hoped t h a t by p r o v i d i n g more r i g o r o u s a n a l y s e s of the host and b i o g e o g r a p h i c d i s t r i b u t i o n s , e v i d e n c e r e f u t i n g or c o r r o b o r a t i n g t h e s e two hypotheses w i l l be o b t a i n e d . 7 I I . PHYLOGENETIC ANALYSIS OF THE SUPERORDER AMPHILINIPEA POCHE, 1922 INTRODUCTION The a m p h i l i n i d e a n s a r e a s m a l l group of p l a t y h e l m i n t h s p a r a s i t i z i n g f r e s h w a t e r and e u r y h a l i n e t e l e o s t s and t u r t l e s . They a r e c o n s i d e r e d t o be the s i s t e r group of the e u c e s t o d e s or t r u e tapeworms because of the complete i n v a g i n a t i o n of the l a r v a l h a p t o r (cercomer) d u r i n g development (Brooks e t a l . , 1985a). The monophyly of the a m p h i l i n i d s can be e s t a b l i s h e d from the p o s t e r i o r l o c a t i o n of male and v a g i n a l p o r e s i n a l l known s p e c i e s . Much of the e a r l y work on t h e a m p h i l i n i d e a n s was concerned w i t h t h e i r r e l a t i o n s h i p t o o t h e r p a r a s i t i c p l a t y h e l m i n t h s . The type s p e c i e s , Amphi1ina f o l i a c e a , was d e s c r i b e d by R u d o l p h i (1819, i n D i e s i n g , 1850) from t h e A t l a n t i c s t u r g e o n , A c i p e n s e r  s t u r i o L. R u d o l p h i c o n s i d e r e d t h i s s p e c i e s t o be a trematode and p l a c e d i t i n the genus Monostoma. A resemblance t o the c e s t o d e s was f i r s t n oted by D u j a r d i n (1845, i n Braun, 1889), who s u g g e s t e d t h a t the specimens d e s c r i b e d by R u d o l p h i were i s o l a t e d p r o g l o t t i d s . D i e s i n g (1850) c o n t i n u e d t o p l a c e t h i s s p e c i e s w i t h the monostomes; he a l s o d e s c r i b e d a second a m p h i l i n i d s p e c i e s under the name Monostoma l i g u l o i d e a . The p r e s e n c e of a mouth or pharynx l e d Wedl (1855, i n Braun, 1889) t o f a v o r placement w i t h the t r e m a t o d e s . Wagener (1858, i n Wardle and McLeod, 1952) e s t a b l i s h e d the genus Amphi1ina; he was a l s o the 8 f i r s t t o n o t i c e a resemblance t o G y r o c o t y l e . A m p h i l i n i d e a n s were c o n s i d e r e d t o be t r a n s i t i o n a l forms between trematodes and c e s t o d e s by Grimm (1871, i n Braun, 1889). T h i s p o s i t i o n was a l s o adopted by M o n t i c e l l i (1892) when he e s t a b l i s h e d the S u b c l a s s C e s t o d a r i a . Poche (1922) made the f i r s t attempt t o s t u d y the s y s t e m a t i c r e l a t i o n s h i p s of a m p h i l i n i d e a n s . He e s t a b l i s h e d the Order A m p h i l i n i d e a and e v a l u a t e d the s t a t u s of the f o u r d e s c r i b e d s p e c i e s . Two r e d e s c r i p t i o n s of Amphi1ina 1 i q u l o i d e a D i e s i n g , 1850 ( M o n t i c e l l i , 1892; J a n i c k i , 1908) were i n f a c t d e s c r i p t i o n s of d i s t i n c t s p e c i e s . Two new s p e c i e s , S c h i z o c h o e r u s 1 i g u l o i d e u s and N e s o l e c i t h u s j a n i c k i i , were proposed as r e p l a c e m e n t s . G i g a n t o l i n a was e s t a b l i s h e d t o accommodate a s p e c i e s d e s c r i b e d as A m p h i l i n a magna from a percomorph i n S r i Lanka ( S o u t h w e l l , 1915). A m p h i l i n a n e r e t i n a , r e p o r t e d from a European s t u r g e o n by S a l e n s k y (1874), was not r e c o g n i z e d as a v a l i d s p e c i e s . Thus the genus Amphi1ina was r e s t r i c t e d so as t o i n c l u d e o n l y the type s p e c i e s , A. f o l i a c e a , and the a m p h i l i n i d e a n s were d i v i d e d i n t o f o u r monotypic genera. A m p h i l i n a paragonopora, d e s c r i b e d from a c a t f i s h i n I n d i a by Woodland (1923b) was a l s o t r a n s f e r r e d t o a new monotypic genus, G e p h y r o l i n a , by Poche i n a l a t e r r e v i s i o n (Poche, 1926a). In the o n l y o t h e r r e v i s i o n of the a m p h i l i n i d e a n s ( D u b i n i n a , 1982) e i g h t a m p h i l i n i d e a n s p e c i e s a r e r e c o g n i z e d . B u i l d i n g on the work of Poche (1922, 1926a), D u b i n i n a r e c o g n i z e d an a d d i t i o n a l f o u r of the n i n e s p e c i e s d e s c r i b e d s i n c e the second r e v i s i o n . A u s t r a m p h i l i n a e l o n g a t a J o h n s t o n , 1934 was d e s c r i b e d 9 from an A u s t r a l i a n f r e s h w a t e r t u r t l e . I h l e and I h l e - L a n d e n b e r g (1932) d e s c r i b e d the same s p e c i e s i n d e p e n d e n t l y the f o l l o w i n g y e a r , as noted by J o h n s t o n (1934). Two a d d i t i o n a l s p e c i e s have been d e s c r i b e d from s t u r g e o n : Amphi1ina j a p o n i c a Goto and I s h i i , 1936 and Amphi1ina b i p u n c t a t a R i s e r , 1948. Amphi1ina b i p u n c t a t a was c o n s i d e r e d a synonym of Amphi1ina j a p o n i c a (see a l s o D u b i n i n a , 1962). H u n t e r o i d e s m y s t e i J o h r i , 1959, o r i g i n a l l y r e p o r t e d as a c a r y o p h y l l i d s p e c i e s from a c a t f i s h , was i d e n t i f i e d as am a m p h i l i n i d e a n by Joyeux and Baer (1961). D u b i n i n a (1982) c o n s i d e r e d t h i s s p e c i e s a synonym of G e p h y r o l i n a  paragonopora Woodland, 1923. Two new a m p h i l i n i d e a n s p e c i e s have been d e s c r i b e d from percomorphs i n the I n d i a n Ocean, Gyrometra  a l b o t a e n i a Yamaguti, 1954 and Gyrometra kunduchi K h a l i l , 1977. D u b i n i n a (1982) c o n s i d e r e d b o t h of t h e s e s p e c i e s t o be synonyms of G i g a n t o l i n a magna S o u t h w e l l , 1915. The l a s t s p e c i e s r e c o g n i z e d i n the r e v i s i o n of D u b i n i n a ( 1 982) i s N e s o l e c i t h u s  a f r i c a n u s Donges and H a r d e r , 1966. Few a t t e m p t s have been made t o c o n s t r u c t s c e n a r i o s t o e x p l a i n the e v o l u t i o n of t h e a m p h i l i n i d e a n s . I n t e r e s t i n the group has been p r i m a r i l y s t i m u l a t e d by t h e l i f e c y c l e . The l i f e c y c l e s of o n l y t h r e e a m p h i l i n i d s p e c i e s have been i n v e s t i g a t e d (Amphi1ina f o l i a c e a : J a n i c k i , 1928; D u b i n i n a , 1982; Amphi1ina  j a p o n i c a : C o l e , 1968; and G i g a n t o l i n a e l o n g a t a : Rohde and G e o r g i , 1983); i n two c a s e s (A. f o l i a c e a , G. e l o n g a t a ) , f r e s h w a t e r c r u s t a c e a n s have been i m p l i c a t e d as i n t e r m e d i a t e h o s t s . The c o m b i n a t i o n of p i s c i n e and c r u s t a c e a n h o s t s resembles the l i f e c y c l e s of p s e u d o p h y l l i d e a n c e s t o d e s . J a n i c k i 10 (1916, i n Donges and Harder,1966) was l e d by t h i s resemblance t o suggest t h a t t h e a m p h i l i n i d e a n s a r e s e x u a l l y mature p l e r o c e r c o i d l a r v a e which a t one time had a s t r o b i l a t e form p a r a s i t i z i n g n o w — e x t i n c t v e r t e b r a t e s . D u b i n i n a (1978) has suggested i n s t e a d t h a t the a m p h i l i n i d e a n s were o r i g i n a l l y p a r a s i t e s of c r u s t a c e a n s . A p h y l o g e n e t i c a n a l y s i s of the c e r c o m e r i a n s (Brooks e t a l . , I985aa) has f a i l e d t o f i n d c o r r o b o r a t i o n f o r e i t h e r of t h e s e h y p o t h e s e s . I n s t e a d , i t appears t h a t the v e r t e b r a t e h o s t of the c e s t o i d e a n s i s the p l e s i o m o r p h i c h o s t and t h a t the absence of c h a r a c t e r i s t i c s of c e s t o d e s i n the a m p h i l i n i d e a n s i s p l e s i o m o r p h i c , and not the r e s u l t of secondary l o s s e s . S e v e r a l of the a u t h o r s c i t e d above have suggested t h a t the a m p h i l i n i d e a n s a r e p h y l o g e n e t i c a l l y o l d , and a r e the remnants of a once w i d e s p r e a d p l a t y h e l m i n t h group. E v i d e n c e f o r t h i s h y p o t h e s i s has come from p e r c e i v e d m o r p h o l o g i c a l d i s p a r i t i e s among s p e c i e s as w e l l as the d i s j u n c t h o s t and b i o g e o g r a p h i c d i s t r i b u t i o n s . The s y s t e m a t i c r e l a t i o n s h i p s of the a m p h i l i n i d e a n s a r e i n need of r e e v a l u a t i o n . There has not been an e x t e n s i v e r e v i s i o n of the group u t i l i z i n g a p h y l o g e n e t i c approach. A p h y l o g e n e t i c a n a l y s i s of t h e group has been performed i n o r d e r t o e s t a b l i s h a h y p o t h e s i s of p h y l o g e n e t i c r e l a t i o n s h i p . Such a h y p o t h e s i s may p e r m i t a s i m p l i f i c a t i o n of the taxonomy. In a d d i t i o n , the p h y l o g e n e t i c a n a l y s i s may p r o v i d e new i n f o r m a t i o n t o t e s t the h y p o t h e s i s of r e l a t i o n s h i p f o r the c e r c o m e r i a n s (Brooks e t a l . , 1985a). 11 A h y p o t h e s i s of p h y l o g e n e t i c r e l a t i o n s h i p summarizes the p a t t e r n s produced by e v o l u t i o n , and i t can t h e r e f o r e s e r v e as an e m p i r i c a l t e s t of hypotheses of e v o l u t i o n a r y p r o c e s s ( P l a t n i c k , 1979; W i l e y , 1981). A p h y l o g e n e t i c a n a l y s i s of the a m p h i l i n i d e a n s can t h e r e f o r e p e r m i t i n f e r e n c e s c o n c e r n i n g the h i s t o r i c a l e c o l o g y of the group t o be t e s t e d . Of p a r t i c u l a r i n t e r e s t f o r the a m p h i l i n i d e a n s i s whether t h e i r host d i s t r i b u t i o n c o u l d be the r e s u l t of c o e v o l u t i o n . U n f o r t u n a t e l y , the l a c k of i n f o r m a t i o n on l i f e c y c l e s p r e c l u d e s i n v e s t i g a t i o n of the e v o l u t i o n of the a s s o c i a t i o n w i t h an i n t e r m e d i a t e host a t t h i s t i m e . A second q u e s t i o n of i n t e r e s t i s whether the g e o g r a p h i c d i s t r i b u t i o n c o u l d be the r e s u l t of v i c a r i a n c e . S i n c e the h o s t and b i o g e o g r a p h i c d i s t r i b u t i o n s have been c i t e d as e v i d e n c e t h a t the a m p h i l i n i d e a n s a r e r e l i c t s , the r e s u l t s of i n v e s t i g a t i o n s of the r e l a t i o n s h i p of a m p h i l i n i d e a n s t o t h e i r h o s t s and t o the g e o g r a p h i c a r e a s they i n h a b i t can i n t u r n serve as a t e s t of the h y p o t h e s i s of r e l i c t s t a t u s . METHODS AND MATERIALS C h a r a c t e r t r a n s f o r m a t i o n s e r i e s i n c l u d e d i n the p h y l o g e n e t i c a n a l y s i s were o b t a i n e d t h r o u g h the e x a m i n a t i o n of the a v a i l a b l e p e r t i n e n t l i t e r a t u r e and a l l o b t a i n a b l e specimens. Specimens of a l l d e s c r i b e d s p e c i e s except A m p h i l i n a n e r e t i n a ( S a l e n s k y , 1 8 7 4 ) , H u n t e r o i d e s m y s t e i ( J o h r i , 1959) and Gyrometra  kunduchi ( K h a l i l , 1977) were o b t a i n e d . 12 The f o l l o w i n g i n s t i t u t i o n s l o a n e d specimens: U. S. N a t i o n a l Museum H e l m i n t h o l g i c a l C o l l e c t i o n , B e l t s v i l l e , M a r y l a n d (USNM); B r i t i s h Museum ( N a t u r a l H i s t o r y ) , London (BMNH); Meguro P a r a s i t o l o g i c a l Museum, Tokyo (MPM); A u s t r a l i a n Museum, Sydney (AM); N a t u r h i s t o r i s k a R i k s m u s e e t , Goteborg (NHRM); Museum f u r Naturkunde Humboldt U n i v e r s i t a t , B e r l i n , D.D.R. (MNHU); and Museum N a t i o n a l d ' H i s t o i r e N a t u r e l l e , P a r i s (MNHN). Specimens were examined u s i n g a s t e r e o m i c r o s c o p e or compound m i c r o s c o p e ; d rawings were p r e p a r e d w i t h the a i d of a d r awing tube or m i c r o p r o j e c t o r . The d a t a were a n a l y z e d u s i n g both H e n n i g i a n a r g u m e n t a t i o n and the PHYSYS computer package f o r q u a n t i t a t i v e s y s t e m a t i c s d e v e l o p e d by D r s . James S. F a r r i s and Mary F. M i c k e v i c h . T r a n s f o r m a t i o n s e r i e s were i d e n t i f i e d u s i n g the outgroup method of comparison (see H e nnig, 1966; W i l e y , 1981; Brooks e_t a l . , 1984). Three o u t g r o u p s , the monogeneans, g y r o c o t y l i d e a n s and tapeworms, were used i n o r d e r t o m i n i m i z e a m b i g u i t i e s r e s u l t i n g from e v o l u t i o n of the o u t g r o u p t a x a (see Maddison e_t a l . , 1984). For c h a r a c t e r i s t i c s not found i n the study group, an a p p r o p r i a t e f u n c t i o n a l o u t g r o u p w i t h i n the study group was employed, f o l l o w i n g the methods of Watrous and Wheeler (1981). The f i t of i n d i v i d u a l t r a n s f o r m a t i o n s e r i e s was checked u s i n g F a r r i s o p t i m i z a t i o n (see F a r r i s , 1970). P r e s e n t e d i n f o r m a t i o n i n c l u d e s : ( l ) the c h a r a c t e r a n a l y s i s , i n c l u d i n g a d i s c u s s i o n of the t e r m i n o l o g y employed i n a m p h i l i n i d e a n s y s t e m a t i c s ; (2) p h y l o g e n e t i c d i a g n o s e s of the one f a m i l y , two s u b f a m i l i e s , t h r e e genera and e i g h t s p e c i e s 13 r e c o g n i z e d , i n c l u d i n g (a) a p a r t i a l l i s t of synonyms, (b) a l i s t of t h e specimens examined, (c) a l i s t of h o s t s , and (d) a l i s t of l o c a l i t i e s ; (3) a d i s c u s s i o n of s p e c i e s i n q u i r e n d a e ; (4) a key t o the s p e c i e s of a m p h i l i n i d e a n s (5) a d i s c u s s i o n of h o s t -p a r a s i t e c o e v o l u t i o n i n t h e a m p h i l i n i d e a n s ; and (6) a d i s c u s s i o n of the b i o g e o g r a p h i c d i s t r i b u t i o n of the a m p h i l i n i d e a n s . Because the male, v a g i n a l and e x c r e t o r y p o r e s a r e l o c a t e d i n the p o s t e r i o r margin i n most s p e c i e s and the because the u t e r i n e pore empties i n t o the a p i c a l i n v a g i n a t i o n , the d o r s o v e n t r a l o r i e n t a t i o n of a m p h i l i n i d e a n s i s p r o b l e m a t i c . An a r b i t r a r y assignment of o r i e n t a t i o n must t h e r e f o r e be made. When the male duct i s t o the r i g h t of the v a g i n a , I c o n s i d e r the specimen t o be v e n t r a l s i d e up. T h i s i s the o r i e n t a t i o n used by Poche (1922, 1925, 1926a,b). In the c h a r a c t e r a n a l y s i s s e c t i o n , 0 i s always used t o r e p r e s e n t the p l e s i o m o r p h i c c o n d i t i o n f o r the n u m e r i c a l c o d i n g . A l l of the i n f o r m a t i o n used i n the p h y l o g e n e t i c a n a l y s i s was o b t a i n e d from d i r e c t e x a m i n a t i o n of specimens u n l e s s noted o t h e r w i s e . The t e r m i n o l o g y employed c o r r e s p o n d s , i n g e n e r a l , t o p r e v i o u s usage; e x c e p t i o n s a r e noted i n the t e x t (see Poche, 1926a; Fuhrman, 1931; Joyeux and Baer, 1961; D u b i n i n a , 1982). Because r e l a t i v e l y few a m p h i l i n i d s p e c i e s c o u l d be o b t a i n e d f o r s t u d y , i t i s n e c e s s a r y t o a d d r e s s the problem of d i s t o r t i o n i n p r e s e r v a t i o n . Wherever p o s s i b l e , specimens from more than one c o l l e c t i o n were examined. T h i s p r o v i d e d an e s t i m a t e of both i n t r a s p e c i f i c v a r i a t i o n and of the degree of d i s t o r t i o n . Where l a r g e r numbers of specimens c o u l d not be compared, i t was 14 n e c e s s a r y t o e x t r a p o l a t e from o b s e r v a t i o n s of the v a r i a b i l i t y i n s p e c i e s which a r e b e t t e r r e p r e s e n t e d i n museum c o l l e c t i o n s . CHARACTER ANALYSIS 1. Cercomer hook number. Each cercomeromorph taxon p o s s e s s e s a d i f f e r e n t number of cercomer hooks so i d e n t i f i c a t i o n of a t r a n s f o r m a t i o n s e r i e s i s d i f f i c u l t (see f i g . 1 ) . A m p h i l i n i d e a n s p o s s e s s t e n hooks, f o u r d i f f e r i n g e m b r y o l o g i c a l l y and c h e m i c a l l y from t h e r e m a i n i n g s i x . The l a t t e r group of hooks appears i d e n t i c a l w i t h the s i x hooks of c e s t o d e s . S i n c e the c h e m i c a l c o m p o s i t i o n of the hooks i n the group of f o u r i s uni q u e , i t c o u l d r e p r e s e n t • an e v o l u t i o n a r y n o v e l t y . A l t e r n a t i v e l y , a d e l a y i n the development of the hooks c o u l d e x p l a i n b o t h the p r e s e n c e of f o u r s m a l l e r hooks i n a m p h i l i n i d e a n s and the p r e s e n c e of o n l y s i x hooks i n c e s t o d e s . In e i t h e r c a s e , the p r e s e n c e of two groups of hooks can be c o n s i d e r e d a synapomorphy f o r the a m p h i l i n i d e a n s . The p l e s i o m o r p h i c s t a t e i s t h e presence of cercomer hooks of a s i n g l e type (0) and the apomorphic s t a t e i s the p r e s e n c e of two t y p e s of hooks ( 1 ) . 2. Male pore p o s i t i o n . I n a l l known a m p h i l i n i d s , t h e male pore i s l o c a t e d i n the p o s t e r i o r h a l f of the body. In " a l l o t h e r cercomeromorphs the male pore i s l o c a t e d a n t e r i o r l y . The l o c a t i o n of the male pore a t the a n t e r i o r end of the body i s 1 5 c o n s i d e r e d p l e s i o m o r p h i c ( 0 ) , w h i l e the p o s t e r i o r l o c a t i o n of t h e male pore i s c o n s i d e r e d apomophic ( 1 ) . 3. V a g i n a l pore p o s i t i o n . In a l l known a m p h i l i n i d s , the v a g i n a l pore i s a l s o l o c a t e d i n the p o s t e r i o r h a l f of the body. In a l l o t h e r cercomeromorphs the v a g i n a l pore i s l o c a t e d a n t e r i o r l y ; t h i s i s the p l e s i o m o r p h i c s t a t e ( 0 ) . The presence of the v a g i n a l pore a t the p o s t e r i o r end i s c o n s i d e r e d apomorphic ( 1 ) . 4. Body shape. Three body shapes are o b s e r v e d among the a m p h i l i n i d e a n s : e l l i p t i c a l , f u s i f o r m and e l o n g a t e (see f i g . 3 ) . The e l o n g a t e shape i s shared w i t h o t h e r cercomeromorphs, most n o t a b l y the c e s t o d e s , and i s t h e r e f o r e c o n s i d e r e d p l e s i o m o r p h i c ( 0 ) . The b e s t f i t i s o b t a i n e d when the two apomorphic body shapes, e l l i p t i c a l and f u s i f o r m , a r e c o n s i d e r e d t o have a r i s e n i n d e p e n d e n t l y . The t h r e e body shapes have been r e p r e s e n t e d i n the m a t r i x u s i n g a m o d i f i c a t i o n of a d d i t i v e b i n a r y c o d i n g i n which component l i n e a r t r a n s f o r m a t i o n s e r i e s a r e i d e n t i f i e d and coded as independent homologous s e r i e s (see f i g . 3 ) . T h i s method of c o d i n g r e s u l t s i n a more compact d a t a s e t . In t h i s c a s e , t h e n , the e l o n g a t e body shape i s coded as ( 0 , 0 ) , the f u s i f o r m shape as (0,1) and the e l l i p t i c a l body as ( 1 , 0 ) . 5. Tegumental s u r f a c e o r n a m e n t a t i o n . Tegumental s u r f a c e o r n a m e n t a t i o n may t a k e the form of i r r e g u l a r r i d g e s and d e p r e s s i o n s or of r e g u l a r c o n c e n t r i c a n n u l a t i o n s , i n both cases 16 c o v e r i n g a l l or n e a r l y a l l of the body s u r f a c e (see f i g . 4 ) . Such tegumental s u r f a c e o r n a m e n t a t i o n i s not o b s e r v e d i n the outgroups and the presence of a smooth tegument i s c o n s i d e r e d p l e s i o m o r p h i c ( 0 ) . Tegumental o r n a m e n t a t i o n was not v i s i b l e i n the specimens of S c h i z o c h o e r u s paragonopora I examined. A honeycomb or r e t i c u l a t e p a t t e r n was observed by Poche (1925) and D u b i n i n a (1982), however. I t appears l i k e l y t h a t the smooth s u r f a c e I obs e r v e d i s an a r t i f a c t , and t h a t the tegument of S.  paragonopora has i r r e g u l a r r i d g e s and d e p r e s s i o n s . A n n u l a t i o n s appear t o be d e r i v e d from the i r r e g u l a r r i d g e s . C o d i n g i s as f o l l o w s : o r n a m e n t a t i o n a b s e n t , ( 0 ) ; p r e s e n t and i r r e g u l a r ( 1 ) ; and p r e s e n t i n the form of c o n c e n t r i c a n n u l a t i o n s ( 2 ) . 6. Development of p h a r y n g e a l r e t r a c t o r m u s c l e s . A c c o r d i n g t o Brooks e_t a l . (1985a), the a p i c a l i n v a g i n a t i o n of the a m p h i l i n i d s i s a c t u a l l y a v e s t i g i a l pharynx. T h i s s t r u c t u r e may be a t l e a s t p a r t i a l l y e v e r t e d ; specimens are u s u a l l y f i x e d w i t h the pharynx r e t r a c t e d (Woodland, 1923b). The m u s c l e s a s s o c i a t e d w i t h the e v e r s i o n and r e t r a c t i o n of t h i s s t r u c t u r e may be weakly d e v e l o p e d ( p l e s i o m o r p h i c ; f i g s . 9,10,15,16) or s t r o n g l y d e v e l o p e d (apomorphic; f i g s . 11,12,13,14). Woodland (1923b) suggested t h a t the muscles a s s o c i a t e d w i t h t h e pharynx f u n c t i o n i n b u r r o w i n g through the body w a l l . He t h e r e f o r e c a l l e d t h i s s t r u c t u r e t h e b o r i n g muscle. 7. P o s t e r i o r margin m o d i f i c a t i o n s . Some a m p h i l i n i d s have a p o s t e r i o r d e p r e s s i o n w i t h one or both g e n i t a l p o r e s opening 17 t h r o u g h a s m a l l p a p i l l a ( f i g s . 11,12,13,14). G i g a n t o l i n a magna has a v e r y l a r g e p a p i l l a , s t i l l s i t u a t e d i n a d e p r e s s i o n ( f i g . 16). The r e m a i n i n g s p e c i e s show e v i d e n c e of a d e p r e s s i o n o n l y when f i x e d i n a c o n t r a c t e d s t a t e ( f i g s . 9,10). The absence of a p a p i l l a i s c o n s i d e r e d p l e s i o m o p h i c (0) as such a s t r u c t u r e does not form i n the tapeworms, a l t h o u g h i n v e r s i o n of the cercomer does o c c u r . The l a r g e p a p i l l a i s an autapomorphy, and i s c o n s i d e r e d t o be d e r i v e d from the s m a l l p a p i l l a . P resence of a s m a l l p a p i l l a i s coded as (1) and a l a r g e p a p i l l a as ( 2 ) . 8. Caudal l o b e s . The p o s t e r i o r d e p r e s s i o n of S c h i z o c h o e r u s  paragonopora has on e i t h e r s i d e a t h i c k l o b e of t i s s u e (see f i g . 11). T h i s appears t o be a unique t r a i t ; t h e absence of c a u d a l l o b e s i s c o n s i d e r e d p l e s i o m o r p h i c (0) and the p r e s e n c e of c a u d a l l o b e s i s c o n s i d e r e d apomorphic ( 1 ) . 9. T e s t e s i n l a t e r a l bands. The t e s t e s of a m p h i l i n i d e a n s a r e f o l l i c u l a r and a r e i n l a t e r a l bands r u n n i n g most of the body l e n g t h . Other cercomeromorphs have l a t e r a l t e s t i c u l a r bands so t h i s i s c o n s i d e r e d the p l e s i o m o r p h i c s t a t e ( 0 ) . Two d e r i v e d s t a t e s a r e o b s e r v e d . In t h e f i r s t , the t e s t i c u l a r bands fan out p o s t e r i o r l y , c r o s s i n g over the u t e r i n e c o i l s ( f i g . 10). In the second, t h e t e s t e s on one s i d e fan out p o s t e r i o r l y , and on the o t h e r s i d e a n t e r i o r l y ( f i g . 9 ) . In the l a t t e r case the t e s t e s have t h e appearance of b e i n g s c a t t e r e d t h r o u g h o u t the parenchyma. The d e r i v e d s t a t e s a r e o b s e r v e d i n a s i n g l e s p e c i e s each, and the two s p e c i e s a r e s i s t e r s p e c i e s , making an 18 assignment of p o l a r i t y f o r t h e s e two s t a t e s somewhat a r b i t r a r y . The former of t h e s e seems t o be a more l i k e l y i n t e r m e d i a t e . Coding i s t h e r e f o r e as f o l l o w s : l a t e r a l bands p r e s e n t , ( 0 ) ; p a r t i a l l y d i s r u p t e d bands, ( 1 ) ; and s c a t t e r e d t e s t e s , ( 2 ) . 10. T e s t i c u l a r band w i d t h . Some a m p h i l i n i d e a n s have t e s t i c u l a r bands r a n g i n g from one t o f i v e t e s t e s i n w i d t h , a p p a r e n t l y w i t h no p a r t i c u l a r o r i e n t a t i o n r e l a t i v e t o the vasa e f f e r e n t i a ( p l e s i o m o r p h i c ; see f i g s . 15 and 16 f o r example). Other a m p h i l i n i d e a n s p o s s e s s t e s t i c u l a r bands which a r e o n l y one or two t e s t e s wide, w i t h t e s t e s i n p a i r s on e i t h e r s i d e of the vasa e f f e r e n t i a f o r most of the l e n g t h ; t h i s i s c o n s i d e r e d apomorphic ( 1 ; see f i g s . 11, 12 f o r example). 11. C o n f o r m a t i o n of vas d e f e r e n s . The vas d e f e r e n s may be c o i l e d ( p l e s i o m o r p h i c ) or c u r v e d , but not c o i l e d (apomorphic; compare f i g s . 15, 16 t o f i g s . 9-14). 12. V a g i n a c r o s s i n g the male d u c t . In some a m p h i l i n i d e a n s p e c i e s , the v a g i n a c r o s s e s over the male duct (see f i g . 5 ) . Absence of t h i s c h a r a c t e r i s t i c i s c o n s i d e r e d p l e s i o m o p h i c ( 0 ) . The p o i n t of o v e r l a p may be a t the l e v e l of the vas d e f e r e n s ( i . e . p r o x i m a l t o the e j a c u l a t o r y b u l b ) or of the e j a c u l a t o r y duct ( d i s t a l t o the e j a c u l a t o r y b u l b ) . .In t h i s c a s e , s i n c e both of t h e s e s t a t e s a r e autapomophies, and s i n c e they a r e found i n t a x a which a r e s i s t e r s p e c i e s , the c o d i n g of the two apomorphic s t a t e s i s somewhat a r b i t r a r y . The former i s coded as (1) and 19 the l a t t e r i s coded as ( 2 ) . 13. G e n i t a l pores s e p a r a t e or common. Separate g e n i t a l p o r e s a r e o b s e r v e d i n most a m p h i l i n i d e a n s as w e l l as i n most o t h e r cercomeromoph t a x a ; t h i s t h e r e f o r e r e p r e s e n t s the p l e s i o m o p h i c c o n d i t i o n . The presence of a common g e n i t a l pore i s c o n s i d e r e d an apomorphic t r a i t . The pre s e n c e of a common g e n i t a l pore has o n l y been p r o p e r l y documented f o r G i q a n t o l i n a e l o n q a t a ( I h l e and I h l e - L a n d e n b e r g , 1932). There has been some debate as t o whether S c h i z o c h o e r u s paragonopora a l s o has a common p o r e . A c c o r d i n g t o Woodland (1923b) the pores a r e i n v e r y c l o s e p r o x i m i t y t o each o t h e r , g i v i n g the appearance of a common p o r e . A c c o r d i n g t o Fuhrmann (1931), however, a g e n i t a l a t r i u m i s p r e s e n t . E x i s t i n g specimens a r e i n poor c o n d i t i o n , and i t i s d i f f i c u l t t o t e l l where the male duct t e r m i n a t e s . I t appears t o me, however, t o open s e p a r a t e l y from the v a g i n a l pore (see f i g . 11). C o n f i r m a t i o n must a w a i t the c o l l e c t i o n and s e c t i o n i n g of new specimens. In t h i s a n a l y s i s , I have assumed t h a t Woodland's o b s e r v a t i o n s a r e c o r r e c t . The presence of s e p a r a t e g e n i t a l p o r e s i s c o n s i d e r e d p l e s i o m o r p h i c ( 0 ) , and the pre s e n c e of a common pore i s c o n s i d e r e d apomorphic ( 1 ) . 14. V a g i n a s i n g l e or b i f u r c a t e . In most cercomeromorphs, the v a g i n a i s s i n g l e . Some p o l y o p i s t h o c o t y l e a n monogeneans po s s e s s b i f u r c a t e l a t e r a l v a g i n a e . A m p h i l i n i d e a n s may p o s s e s s e i t h e r a s i n g l e v a g i n a or a T-shaped b i f u r c a t e v a g i n a opening t o the d o r s a l and v e n t r a l s u r f a c e s . The best f i t i s o b t a i n e d f o r the 20 h y p otheses o f r e l a t i o n s h i p f o r bo t h the cercomeromorphs and the a m p h i l i n i d e a n s when the p r e s e n c e of a s i n g l e v a g i n a i s c o n s i d e r e d p l e s i o m o r p h i c (0) and the presence of a d o r s o v e n t r a l l y b i f u r c a t e v a g i n a i s c o n s i d e r e d apomorphic ( 1 ) . 15. M u s c u l a r i t y of the v a g i n a l p o r e . In a l l a m p h i l i n i d s t h e v a g i n a l pore i s muscular ( p l e s i o m o r p h i c ; 0 ) . I n G i g a n t o l i n a  magna, the v a g i n a l pore i s su r r o u n d e d by an e x t r e m e l y t h i c k muscle r i n g which i s r a i s e d above the s u r f a c e of the body (apomorphic; see f i g . 16). 16. V a g i n a l c o n f o r m a t i o n . The v a g i n a i n a m p h i l i n i d e a n s may be c u r v e d or o n l y s l i g h t l y c o i l e d ( p l e s i o m o r p h i c ; 0; f i g s . 9, 10, 15, 16). A l t e r n a t i v e l y , the v a g i n a may be s t r o n g l y s i n u o u s l y c o i l e d (apomorphic; 1; f i g s . 11-14). 17. S e m i n a l r e c e p t a c l e s i z e . The t e r m i n o l o g y p r e v i o u s l y used t o d e s c r i b e t h e s e m i n a l r e c e p t a c l e and i t s a s s o c i a t e d s t r u c t u r e s i s c o n f u s i n g , and i s i n need of c l a r i f i c a t i o n . Here, the term " s e m i n a l r e c e p t a c l e ' i s a p p l i e d o n l y t o a d i l a t e d r e g i o n of the v a g i n a . I n most cercomeromorphs, the s e m i n a l r e c e p t a c l e i s f a i r l y s m a l l ( s m a l l e r than the o v a r y , f o r example; see f i g s . 9,10). T h i s i s c o n s i d e r e d p l e s i o m o r p h i c ( 0 ) . In some a m p h i l i n i d e a n s , the s e m i n a l r e c e p t a c l e i s as l a r g e as or l a r g e r than the o v a r y . T h i s i s c o n s i d e r e d apomorphic ( 1 ; f i g s . 12-16). 21 18. V a g i n a l duct e x t e n s i o n s . The term ' a c c e s s o r y s e m i n a l r e c e p t a c l e ' has been a p p l i e d t o two s t r u c t u r e s (see a l s o c h a r a c t e r 19, be l o w ) . A c c e s s o r y s e m i n a l r e c e p t a c l e s may form as d i l a t i o n s of the v a g i n a (see f i g . 6 ) . These s t r u c t u r e s a r e uni q u e ; t h e absence of v a g i n a l duct e x t e n s i o n s i s t h e r e f o r e c o n s i d e r e d p l e s i o m o r p h i c ( 0 ) , and t h e presence i s apomorphic ( 1 ) . 19. S e m i n a l duct d i l a t i o n s . A c c e s o r y s e m i n a l r e c e p t a c l e s may a l s o form as d i l a t i o n s of the s e m i n a l duct (see f i g . 6 ) . These s t r u c t u r e s a r e a l s o u n i q u e ; the absence of s e m i n a l duct d i l a t i o n s i s t h e r e f o r e c o n s i d e r e d p l e s i o m o r p h i c ( 0 ) , and the pre s e n c e i s apomorphic ( 1 ) . 20. Ovary shape. Four shapes a r e o b s e r v e d (see f i g . 7 ) : (a) b i l o b e d , a s y m m e t r i c a l and c o a r s e l y l o b a t e ; (b) b i l o b e d , s y m m e t r i c a l and f i n e l y l o b a t e ; (c) s i n g l e but k i d n e y shaped, thus h a v i n g some degree of b i l o b e d s t r u c t u r e , e n t i r e and smooth; and (d) s i n g l e , i r r e g u l a r l y shaped, and e n t i r e but w i t h a rough s u r f a c e . O v a r i e s c o n s i s t i n g of e i t h e r one l o b e or two a r e ob s e r v e d i n c e r c o m e r i a n s , a l t h o u g h t h e most c l o s e l y r e l a t e d groups have b i l o b e d f o l l i c u l a r o v a r i e s . Shape (a) i s c o n s i d e r e d p l e s i o m o r p h i c (0) and shape (c) i s c o n s i d e r e d apomorphic ( 1 ) . The r e m a i n i n g two shapes a r e autapomorphies and the b e s t f i t i s o b t a i n e d when they a r e c o n s i d e r e d t o have been d e r i v e d i n d e p e n d e n t l y from shape ( c ) . Coding i s t h e r e f o r e as f o l l o w s : b i l o b e d , i r r e g u l a r , and l o b a t e ( 0 , 0 ) ; k i d n e y shaped and smooth, 22 ( 1 , 1 ) ; b i l o b e d , s y m m e t r i c a l , and l o b a t e ( 1 , 2 ) ; and s i n g l e and rough, ( 2 , 1 ) . 21. R e l a t i v e p o s i t i o n s of the female g e n i t a l d u c t s . A t r a n s f o r m a t i o n s e r i e s f o r the s p a t i a l r e l a t i o n s h i p s of t h e female r e p r o d u c t i v e s t r u c t u r e s i s p r e s e n t e d i n f i g u r e 8. 22. U t e r i n e c o n f o r m a t i o n . In o t h e r c e s t o d a r i a n s a s i m p l e s i n u o u s l y c o i l e d u t e r u s i s p r e s e n t . In a m p h i l i n i d e a n s , the u t e r u s i s s i n u o u s l y c o i l e d , but i t i s a l s o c o i l e d i n t o an N-shape ( f i g s . 9-14) or l o o p e d over i t s e l f ( f i g s . 15,16). The s i n u o u s u t e r u s i s c o n s i d e r e d p l e s i o m o r p h i c , and the l o o p e d u t e r u s appears t o be d e r i v e d from the N-shaped u t e r u s . The c h a r a c t e r s t a t e s a r e coded as f o l l o w s : s i n u o u s ( 0 ) , N-shaped (1) and l o o p e d ( 2 ) . 23. U t e r i n e pore p o s i t i o n . In a m p h i l i n i d e a n s the u t e r i n e pore i s a s s o c i a t e d w i t h the a p i c a l i n v a g i n a t i o n . T h i s i s an autapomorphic t r a i t of a m p h i l i n i d e a n s . In some s p e c i e s , t h e u t e r u s opens i n t o the base of the a p i c a l i n v a g i n a t i o n (see f i g s . 9, 10, 15, 16). In o t h e r s the u t e r u s extends t o the a n t e r i o r end of the a p i c a l i n v a g i n a t i o n (see f i g s . 15 and 16), and appears t o open t o the body s u r f a c e , r a t h e r than i n t o the a p i c a l i n v a g i n a t i o n . The e x a c t l o c a t i o n of the pore i n these s p e c i e s i s not c l e a r . The b e s t f i t of t h i s c h a r a c t e r t o o t h e r c h a r a c t e r s i n c l u d e d i n t h e a n a l y s i s i s o b t a i n e d when the former c o n d i t i o n i s c o n s i d e r e d p l e s i o m o r p h i c t o the l a t t e r . Coding i s 23 as f o l l o w s : u t e r i n e pore d i s t a l t o the pharynx (outgroup o n l y , 0 ) , u t e r u s opening i n t o t h e p o s t e r i o r end of the pharynx ( 1 ) , u t e r i n e pore a d j a c e n t t o the pharynx ( 2 ) . 24. L o c a t i o n of the d e s c e n d i n g l i m b of the u t e r u s . The de s c e n d i n g l i m b of the N-shaped u t e r u s may be a d j a c e n t t o the f i r s t a s c e n d i n g l i m b or the t e r m i n a l l i m b . Based on the use of a f u n c t i o n a l o u t g r o u p , the former c o n d i t i o n i s c o n s i d e r e d p l e s i o m o r p h i c (0) t o the l a t t e r ( 1 ) . 25. U t e r i n e s i z e . The u t e r u s may occupy more than 75% of the t o t a l body w i d t h ( r e l a t i v e l y p l e s i o m o r p h i c , based on a f u n c t i o n a l outgroup) or l e s s than 50% of the t o t a l body w i d t h ( a p o m o r p h i c ) . 26. S u p e r c o i l i n g of u t e r i n e d u c t . In a l l a m p h i l i n i d s the u t e r u s i s l a t e r a l l y ( s i n u o u s l y ) c o i l e d . In some s p e c i e s , the t e r m i n a l l i m b of the u t e r u s i s s u p e r c o i l e d , i . e . t h e r e a r e a t l e a s t two o r d e r s of c o i l s (see f i g . 9 or 10). The presence of one l e v e l of c o i l s i s p l e s i o m o r p h i c (0) and the presence of two l e v e l s of c o i l i n g i s apomorphic ( 1 ) . 27. D i l a t i o n of u t e r u s . The u t e r i n e duct i n some s p e c i e s of a m p h i l i n i d e a n s i s d i l a t e d r e l a t i v e t o o t h e r s p e c i e s (see f i g s . 15 and 16, f o r example). The absence of d i l a t i o n i s c o n s i d e r e d p l e s i o m o r p h i c ( 0 ) , w h i l e the d i l a t e d c o n d i t i o n i s c o n s i d e r e d apomorphic ( 1 ) . 24 28. Presence of an a t r o p h i e d u t e r i n e d u c t . In most a m p h i l i n i d e a n s the u t e r i n e duct i s of f a i r l y c o n s t a n t d i a m e t e r ; t h i s i s c o n s i d e r e d the p l e s i o m o r p h i c c o n d i t i o n ( 0 ) . In some s p e c i e s of a m p h i l i n i d e a n s the u t e r i n e duct i s a t r o p h i e d r e l a t i v e t o o t h e r s p e c i e s (see f i g s . 12-14); the a t r o p h i e d c o n d i t i o n i s c o n s i d e r e d apomorphic ( 1 ) . 29. Development of v i t e l l i n e f o l l i c l e s . The v i t e l l a r i a of a m p h i l i n i d e a n s may be w e l l d e v e l o p e d , c o n s i s t i n g of dense bands of f o l l i c l e s s e v e r a l f o l l i c l e s t h i c k , w i t h i n d i v i d u a l f o l l i c l e s i d e n t i f i a b l e . A l t e r n a t i v e l y , the v i t e l l a r i a may be p o o r l y d e v e l o p e d , c o n s i s t i n g of narrow bands of i n d i s t i n c t f o l l i c l e s . The former ' c o n d i t i o n i s s h a r e d w i t h most p a r a s i t i c p l a t y h e l m i n t h s , and so i s c o n s i d e r e d p l e s i o m o r p h i c ( 0 ) . The presence of p o o r l y d e v e l o p e d v i t e l l a r i a i s c o n s i d e r e d apomorphic ( 1 ) . 30. Ductus y a m a g u t i i . The p r e c i s e s t r u c t u r e and f u n c t i o n of the d u c t u s y a m a g u t i i i s unknown. The duct emerges from a g l a n d u l a r mass a d j a c e n t t o the s e m i n a l r e c e p t a c l e and extends • a n t e r i o r l y as a s e r i e s of s i n u o u s c o i l s a d j a c e n t t o the t e r m i n a l l i m b of the u t e r u s (see f i g . 16). I t has p r e v i o u s l y been termed the f r o n t a l g l a n d , but t h i s term i s i n a p p r o p r i a t e as the s t r u c t u r e i s not a g l a n d , a l t h o u g h t h e lumen of the duct i s l i n e d w i t h g l a n d c e l l s . In a d d i t i o n , the term " f r o n t a l g l a n d " i s a l s o a p p l i e d t o the i n d i v i d u a l g l a n d c e l l s found a t the a n t e r i o r end of a l l a m p h i l i n i d e a n s (see Hyman, 1951 f o r a 25 d i s c u s s i o n of the term " f r o n t a l g l a n d " ) . The duct has been d e s c r i b e d i n g r e a t e s t d e t a i l by Yamaguti (1954). The name duc t u s y a m a g u t i i i s t h e r e f o r e proposed as a re p l a c e m e n t . The du c t u s y a m a g u t i i i s found o n l y i n G i g a n t o l i n a magna. Absence of t h i s s t r u c t u r e i s c o n s i d e r e d p l e s i o m o r p h i c (0) and presence i s c o n s i d e r e d apomorphic ( 1 ) . CHARACTERS NOT INCLUDED IN THE ANALYSIS Some c h a r a c t e r s used i n p r e v i o u s r e v i s i o n s of the group, but not i n c l u d e d i n my stu d y a r e the pre s e n c e or absence of f r o n t a l g l a n d s , anastomosing v i t e l l i n e d u c t s , l a r v a l hooks, and v a g i n a l s p i n e s or p r o j e c t i o n s , and the a n t e r o p o s t e r i o r e x t e n t of the v i t e l l a r i a . The a n t e r o p o s t e r i o r e x t e n t of the v i t e l l a r i a r e l a t i v e t o the t e s t e s i s v a r i a b l e w i t h i n s p e c i e s , and may be r e l a t e d t o the dev e l o p m e n t a l s t a g e of t h e specimen. F u r t h e r i n v e s t i g a t i o n would be n e c e s s a r y b e f o r e t h i s c h a r a c t e r c o u l d be i n c l u d e d . Anastomosing v i t e l l i n e d u c t s have been o b s e r v e d i n a l l a m p h i l i n i d s p e c i e s r e c o g n i z e d i n t h i s r e v i s i o n . < S i n c e anastomosing v i t e l l i n e d u c t s have been o b s e r v e d i n o t h e r p l a t y h e l m i n t h s , t h i s c h a r a c t e r s t a t e i s c l e a r l y a symplesiomorphy and i s t h e r e f o r e u n i n f o r m a t i v e . F r o n t a l g l a n d s , or i n d i v i d u a l g l a n d c e l l s l o c a t e d around the a p i c a l i n v a g i n a t i o n , appear t o be found i n a l l 26 a m p h i l i n i d e a n s . Gland c e l l s l o c a t e d a t the a n t e r i o r end a r e known i n o t h e r c e r c o m e r i a n s , so t h i s t r a i t has a l s o been c o n s i d e r e d a symplesiomorphy. L a r v a l hooks may or may not be v i s i b l e i n a d u l t a m p h i l i n i d s . R e a b s o r p t i o n of the hooks i s p a r t of the normal development of g y r o c o t y l i d s and c e s t o d e s . Perhaps the a m p h i l i n i d s a re p o l y m o r p h i c f o r t h i s t r a i t , or a l t e r n a t i v e l y , the r e a b s o r p t i o n of the hooks i s d e l a y e d i n comparison w i t h the o t h e r c e s t o d a r i a n t a x a . A d u l t g y r o c o t y l i d s w i t h cercomer hooks ar e o c c a s i o n a l l y o b s e r v e d (Lynch, 1945). V a g i n a l s p i n e s have been o b s e r v e d i n G i g a n t o l i n a e l o n g a t a o n l y . V a g i n a l p r o j e c t i o n s have been obse r v e d i n G i q a n t o l i n a  magna (Yamaguti, 1954), S c h i z o c h o e r u s l i g u l o i d e u s (Poche, 1922), and S c h i z o c h o e r u s a f r i c a n u s (Donges and Har d e r , 1966). A p o s s i b l e e x p l a n a t i o n f o r the s e o b s e r v a t i o n s i s t h a t v a g i n a l p r o j e c t i o n s a r e p r e s e n t i n a l l of the S c h i z o c h o e r i n a e , but t h a t i n one s p e c i e s , G^ e l o n g a t a , t h e s e p r o j e c t i o n s have been s c l e r o t i z e d . R e s o l u t i o n of t h i s t r a n s f o r m a t i o n s e r i e s would r e q u i r e the c o l l e c t i o n of new specimens of a l l of the s p e c i e s i n the S u b f a m i l y S c h i z o c h o e r i n a e . RESULTS A b r a n c h i n g diagram d e p i c t i n g the most p a r s i m o n i o u s h y p o t h e s i s of p h y l o g e n e t i c r e l a t i o n s h i p s among the a m p h i l i n i d e a n s i s shown i n f i g u r e 17. The p h y l o g e n e t i c t r e e i s based on the a n a l y s i s of 27 46 c h a r a c t e r s t a t e s c o m p r i s i n g 34 homologous s e r i e s ; the c h a r a c t e r m a t r i x may be found i n Appendix A ( t a b l e I ) . The c o n s i s t e n c y i n d e x , a measure of t h e goodness of f i t of the c h a r a c t e r s t o the t r e e , i s 89 %, i n d i c a t i n g a v e r y low degree of homoplasy (convergence, p a r a l l e l i s m or r e v e r s a l ) . Diagnoses p r e s e n t e d are p h y l o g e n e t i c d i a g n o s e s ( s e n s u Brooks et a l . , I985aa) summarizing t h e synapomorphic t r a i t s f o r the t a x a . For h i g h e r l e v e l t a x a , the c h a r a c t e r i s t i c s l i s t e d a r e the p l e s i o m o r p h i c s t a t e s f o r the t a x o n . They a r e not i n t e n d e d t o serve as summaries of a l l of the c h a r a c t e r s t a t e s o b s e r v e d w i t h i n any g i v e n t a x o n . Numbers i n the d i a g n o s e s r e f e r t o the numbers i n f i g . 17. P r e v i o u s c l a s s i f i c a t i o n s of the a m p h i l i n i d s (Poche, 1922, 1926a; Fuhrmann, l931;.Joyeux and Baer, 1961; D u b i n i n a , 1982) r e c o g n i z e f o u r t o s i x genera, most of w h i c h a r e monotypic. The l a r g e p r o p o r t i o n of monotypic genera have been j u s t i f i e d on the b a s i s of the s t r i k i n g m o r p h o l o g i c a l d i f f e r e n c e s o b s e r v e d , as w e l l as the v a r i e t y of h o s t s and l o c a l i t i e s . However, i n s p i t e of the l a r g e number of a u t a p o m o r p h i e s , the a m p h i l i n i d s can be d i v i d e d i n t o t h r e e d i s t i n c t c l a d e s , each s u p p o r t e d by s e v e r a l synapomorphies. E x i s t i n g c l a s s i f i c a t i o n s , by e m p h a s i z i n g autapomorphies, obscure the r e l a t i o n s h i p s among t a x a , and t h e r e f o r e do not p e r m i t r o b u s t i n f e r e n c e s c o n c e r n i n g the h i s t o r y of the group t o be made. 28 S u p e r o r d e r A m p h i l i n i d e a Poche, 1922 Cercomeromorphae w i t h cercomer hooks of two s i z e s ( 1 ) . Body f l a t t e n e d and e l o n g a t e . Cercomer i n v a g i n a t e d i n development (see D u b i n i n a , 1982); a d u l t w i t h o u t d e p r e s s i o n i n p o s t e r i o r m a r g in. Tegument c o v e r e d w i t h numerous t i n y r i d g e s and d e p r e s s i o n s ( 4 ) . M u s c u l a r a p i c a l i n v a g i n a t i o n (pharynx) p r e s e n t , but w i t h r e t r a c t o r muscles p o o r l y d e v e l o p e d . T e s t e s s u b g l o b u l a r , round t o e l l i p t i c a l i n o u t l i n e , and i n l a t e r a l bands of v a r i a b l e w i d t h . Vasa e f f e r e n t i a u n i t e l a t e r a l t o median l i n e t o form c o i l e d vas d e f e r e n s . M u s c u l a r e j a c u l a t o r y b u l b p r e s e n t . E j a c u l a t o r y d u c t c u r v e d or l o o s e l y c o i l e d , o pening i n p o s t e r i o r margin ( 2 ) , on or near median l i n e . V a g i n a l pore opening i n p o s t e r o l a t e r a l margin ( 3 ) . V a g i n a c u r v e d or l o o s e l y c o i l e d , d i l a t i n g t o form s m a l l s e m i n a l r e c e p t a c l e . Ovary b i l o b e d and l o b a t e . S h o r t o v i d u c t j o i n i n g w i t h s e m i n a l duct t o form f e r t i l i z a t i o n duct which opens i n t o M e h l i s ' g l a n d . U t e r u s N-shaped and c o i l e d , o c c u p y i n g more than 90% of the t o t a l body w i d t h and l e n g t h . U t e r i n e pore l o c a t e d a t the base of a p i c a l i n v a g i n a t i o n . V i t e l l a r i a f o l l i c u l a r , i n l a t e r a l bands, emptying i n t o a nastomosing v i t e l l i n e d u c t s . P a r a s i t e s of f r e s h w a t e r and e u r y h a l i n e t e l e o s t s and t u r t l e s . C o s m o p o l i t a n . Type s p e c i e s : Amphi1ina f o l i a c e a R u d o l p h i , 1819. 29 Order Amphi1 i n i f o r m e s W i t h the c h a r a c t e r s of t h e i n f r a s u b c l a s s . F a m i l y A m p h i l i n i d a e C l a u s , 1879 W i t h the c h a r a c t e r s of t h e o r d e r . S u b f a m i l y Amphi1 i n i n a e C l a u s , 1879 A m p h i l i n i d a e w i t h e l l i p t i c a l body ( 6 ) . P o s t e r i o r margin w i t h d e p r e s s i o n o n l y when f i x e d i n a c o n t r a c t e d s t a t e . T e s t e s i n l a t e r a l bands of v a r i a b l e w i d t h a n t e r i o r l y , s c a t t e r e d p o s t e r i o r l y ( 7 ) . Vas d e f e r e n s h i g h l y c o i l e d , opening i n t o wide muscular e j a c u l a t o r y b u l b . E j a c u l a t o r y duct c r o s s i n g v a g i n a ( 8 ) ; e j a c u l a t o r y duct and v a g i n a opening i n t o p o s t e r o l a t e r a l body m a r g i n . V a g i n a s i n g l e , l o o s e l y c o i l e d , opening i n t o s m a l l s e m i n a l r e c e p t a c l e . Ovary b i l o b e d , s t e l l a t e , r o t a t e d under s e m i n a l r e c e p t a c l e ( 1 0 ) . U t e r u s l a r g e , o c c u p y i n g more than 90% of t o t a l body l e n g t h and w i d t h . Second a s c e n d i n g l i m b of u t e r u s s u p e r c o i l e d ( 9 ) . Descending l i m b of N-shaped u t e r u s a d j a c e n t t o f i r s t a s c e n d i n g l i m b . P a r a s i t e s of c h o n d r o s t e a n s , e x c l u s i v e l y of the A c i p e n s e r i d a e . E u r a s i a , Japan, n o r t h w e s t e r n N o r t h A m e r i c a . A m p h i l i n a Wagener, 1858. W i t h c h a r a c t e r s of t h e s u b f a m i l y . Type s p e c i e s : A m p h i l i n a  f o l i a c e a R u d o l p h i , 1819. 3 0 A m p h i l i n a f o l i a c e a ( R u d o l p h i , 1819) Wagener, 1858 ( F i g u r e 9) Monostoma f o l i a c e u m R u d o l p h i , 1819: 340-342 ( o r i g i n a l d e s c r i p t i o n , i n A c i p e n s e r s t u r i o , A r m i n i ) ; Monostoma  f o l i a c e u m : D i e s i n g , 1850: 319-320 ( l i s t e d ) . A m p h i l i n a f o l i a c e a Wagener, 1858: 244-249 (new c o m b i n a t i o n ) ; A m p h i l i n a f o l i a c e a : S a l e n s k y , 1874: 293-339, f i g s . 1-4,6-17,19-34 ( s u p p l e m e n t a l m o r p h o l o g i c a l d a t a ) ; Braun, 1889: 436-441 ( l i s t e d ) ; Cohn, 1904: 367-387, f i g s . 1-8 (supplementary m o r p h o l o g i c a l i n f o r m a t i o n ) ; H e i n , 1904: 400-436, f i g s . 1-11 (supplementary m o r p h o l o g i c a l i n f o r m a t i o n ) ; Poche, 1922: 278 (supplementary m o r p h o l o g i c a l i n f o r m a t i o n ) ; Poche, 1925a: 585-618, f i g s . 1-21 (supplementary m o p h o l o g i c a l i n f o r m a t i o n ) ; Fuhrmann, 1931: 159, f i g s . 178, 180-183, 185-188, 191 ( l i s t e d ) ; Yamaguti, 1959: 11-12, P I . 122, f i g . 168 ( l i s t e d ) ; Joyeux and Baer, 1961: 345, f i g s . 235, 236, 244 ( l i s t e d ) ; Donges and Hard e r , 1966: 138 ( l i s t e d ) ; D u b i n i n a , 1962: 452-454, f i g s . 851-852 (supplementary m o r p h o l o g i c a l i n f o r m a t i o n ) ; D u b i n i n a , 1982: 61-65, f i g s . 3, 5-10, 17, 18, 26-28, 30-37 (supplementary m o r p h o l o g i c a l i n f o r m a t i o n ) . A m p h i l i n a n e r e t i n a S a l e n s k y : 1874: 339-340, f i g s . 5,18,35 ( d e s c r i p t i o n from European s t u r g e o n ) . 31 Specimens examined: MNHU #1320 ( s y n t y p e s ) , 3029; NHRM #22; USNM #49513. H o s t s : Huso huso L. , A c i p e n s e r b a e r i B r a n d t , A_^  g u l d e n s t a d t i i B r a n d t , A^ n a c c a r i B o n a p a r t e , A^ n u d i v e n t r i s L o v e t s k y , A. r u t h e n s u s L., A^ s t e l l a t u s P a l l a s , A_^  s t u r i o L ( A c t i n o p t e r y g i i : C h o n d r o s t e i ) . L o c a l i t i e s : E u r a s i a : M e d i t e r r a n e a n , b a s i n s of the B l a c k and C a s p i a n Seas, Lake B a i k a l , r i v e r s d r a i n i n g i n t o t he A r c t i c Ocean. Taxonomic C h a r a c t e r i s t i c s : Body e l l i p t i c a l , 15-35 mm l o n g , and 5-35 mm wide. T e s t e s i n wide bands, f l a r i n g out a n t e r i o r l y , c r o s s i n g both f i r s t a s c e n d i n g and de s c e n d i n g l i m b s of u t e r u s ( 1 1 ) . Vas d e f e r e n s h i g h l y c o i l e d , o p ening i n t o wide muscular e j a c u l a t o r y b u l b ; e j a c u l a t o r y duct c r o s s i n g v a g i n a . P o i n t of o v e r l a p of v a g i n a and male duct i s p r o x i m a l t o the e j a c u l a t o r y b u l b ( 7 ) . Male and v a g i n a l p o r e s w i d e l y s e p a r a t e d , p o s t e r o l a t e r a l , opening t h r o u g h body m a r g i n . Amphi1ina j a p o n i c a Goto and I s h i i , 1936 ( f i g u r e 10) A m p h i l i n a j a p o n i c a Goto and I s h i i , 1936: 81-83, f i g s . 1-3 ( o r i g i n a l d e s c r i p t i o n , from A c i p e n s e r m e d i r o s t r i s as A. mi k a d o i i n J a p a n ) ; Amphi1ina j a p o n i c a : Yamaguti, 1959: 1 2, ( l i s t e d ) ; D u b i n i n a , 1962: 453-454, f i g . 852 ( s u p p l e m e n t a l m o r p h o l o g i c a l i n f o r m a t i o n ) ; D u b i n i n a , 1982: 67-72, f i g s . 32 22, 38-39 ( s u p p l e m e n t a l m o r p h o l o g i c a l i n f o r m a t i o n ) . A m p h i l i n a b i p u n c t a t a R i s e r , 1948 479-485, f i g s . 1 - 8 ( d e s c r i p t i o n from Ac i p e n s e r transmontanus) and A. m e d i r o s t r i s ; A m p h i l i n a b i p u n c t a t a ) - U : Yamaguti, 1959: 12 ( l i s t e d ) ; Donges and H a r d e r , 1966: 138 ( l i s t e d ) A m p h i l i n a f o l i a c e a : Poche, 1922: 277 ( p a r t i m ; l i s t e d ) ; Wardle and McLeod, 1952: 656 ( p a r t i m ; l i s t e d ) . Specimens examined: MPM # 2835 ( h o l o t y p e ) ; USNM # 37091; a d d i t i o n a l specimens from the c o l l e c t i o n s of t h e U n i v e r s i t y of B r i t i s h Columbia and the U n i v e r s i t y of Washington. H o s t s : A c i p e n s e r transmontanus R i c h a r d s o n , A^ m e d i r o s t r i s A y r e s ( s y n . A. m i k a d o i H i l g e n d o r f ) , A_j_ s c h r e n c k i B r a n d t , Huso  d a u r i c u s G e o r g i ( A c t i n o p t e r y g i i : C h o n d r o s t e i ) . L o c a l i t i e s : West c o a s t of N o r t h A m e r i c a , Japan, S a k h a l i n I s l a n d , Kamchatka P e n i n s u l a . Taxonomic c h a r a c t e r i s t i c s : Body e l l i p t i c a l , 12-65 mm l o n g , 5-29 mm wide. T e s t e s i n wide l a t e r a l bands, becoming s c a t t e r e d near the p o s t e r i o r end ( 7 ) . Male duct c r o s s i n g v a g i n a ; e j a c u l a t o r y b u l b p r o x i m a l t o p o i n t of o v e r l a p ( 1 2 ) . Male and female p o r e s s e p a r a t e but a d j a c e n t , opening p o s t e r o l a t e r a l ^ , i n t o body ma r g i n . 33 S u b f a m i l y S c h i z o c h o e r i n a e Poche, 1922 A m p h i l i n i d a e w i t h p o s t e r i o r d e p r e s s i o n p r e s e n t even when f i x e d i n a r e l a x e d s t a t e ( 1 3 ) . P h a r y n g e a l r e t r a c t o r muscles p o o r l y d e v e l o p e d . T e s t e s i n narrow l a t e r a l bands. Vas d e f e r e n s c o i l e d , opening i n t o narrow e j a c u l a t o r y b u l b . E j a c u l a t o r y duct opening t o p o s t e r o l a t e r a l body m a r g i n , near opening of v a g i n a l d u c t . V a g i n a s i n g l e , l o o s e l y c o i l e d , opening i n t o l a r g e s e m i n a l r e c e p t a c l e ( 1 4 ) . Ovary kidney-shaped, smooth, e n t i r e (15,16). P a r a s i t e s of s i l u r i f o r m , o s t e o g l o s s i f o r m and mormyriform f i s h e s . I n d i a , A f r i c a , South A m e r i c a , A u s t r a l i a , I n d i a n Ocean I s l a n d s . Type s p e c i e s , S c h i z o c h o e r u s l i g u l o i d e u s D i e s i n g , 1850. Genus S c h i z o c h o e r u s Poche, 1922 S c h i z o c h o e r i n a e w i t h e l o n g a t e body. P h a r y n g e a l r e t r a c t o r muscles s t r o n g l y d e v e l o p e d ( 2 8 ) . T e s t i c u l a r bands narrow, c o n s i s t i n g of not more than two t e s t e s , r o u g h l y p a i r e d f o r much of l e n g t h ( 2 9 ) . Male duct opening through p o s t e r i o r d e p r e s s i o n . V a g i n a s i n g l e , c o i l e d ( 3 0 ) , opening t h r o u g h p o s t e r i o r d e p r e s s i o n . Seminal duct d i l a t e d t o form a c c e s s o r y s e m i n a l r e c e p t a c l e ( 3 3 ) . U t e r u s N--shaped, s m a l l ( 3 2 ) , o c c u p y i n g l e s s than 50% of t o t a l body w i d t h . U t e r i n e pore a s s o c i a t e d w i t h a p i c a l i n v a g i n a t i o n ( 3 1 ) . S c h i z o c h o e r u s paragonopora (Woodland, 1923) comb, n. (f i g u r e 11) 34 A m p h i l i n a paragonopora Woodland, 1923: 47-84, f i g s . 1-47; A m p h i l i n a paragonopora: S o u t h w e l l , 1928:325-326, f i g . 3; G e p h y r o l i n a paragonopora Poche, 1925: 254-255 ( s u p p l e m e n t a l m o r p h o l o g i c a l i n f o r m a t i o n ) ; G e p h y r o l i n a paragonopora: Fuhrmann, 1931: 160, f i g s . 184, 189 ( l i s t e d ) ; Wardle and McLeod, 1952: 656-657, f i g . 415 ( l i s t e d ) ; Yamaguti, 1959: 12, p i . 18, f i g . 145 ( l i s t e d ) ; Joyeux and Baer, 1961: 346, f i g s . 237,243 ( l i s t e d ) ; Donges and H a r d e r , 1966: 138 ( l i s t e d ) ; D u b i n i n a , 1982: 72-82, f i g s . 4, 12, 13, 19, 40-46 ( s u p p l e m e n t a l m o r p h o l o g i c a l i n f o r m a t i o n ) . H u n t e r o i d e s m y s t e i J o h r i , 1959: 368-374, f i g s . 1-4 ( d e s c r i p t i o n ) . Specimens examined: BMNH #1965.2.17.11-60 H o s t s : A o r i c t h y s seenghala Sykes, A o r i c h t h y s aor H a m i l t o n , (as Macrones a o r , M. s e e n g h a l a ) ; B a g a r i u s b a g a r i u s Boulenger as B a g a r i u s y a r r e l l i ( T e l e o s t e i : S i l u r i f o r m e s ) . L o c a l i t i e s : Ganges and Jumna R i v e r s , I n d i a . Taxonomic c h a r a c t e r i s t i c s : Body e l o n g a t e , 38-43 mm i n l e n g t h , maximum w i d t h l e s s than 5 mm, w i t h body w i d t h n e a r l y u n i f o r m t h r o u g h o u t l e n g t h . P o s t e r i o r end marked by median d e p r e s s i o n ( 1 3 ) , w i t h a l o b e of t i s s u e on e i t h e r s i d e ( 3 4 ) . E j a c u l a t o r y duct c o i l e d , opening i n t o median p o s t e r i o r d e p r e s s i o n ( ? ) . V a g i n a s i n g l e , c o i l e d , opening a d j a c e n t t o male pore i n 35 p o s t e r i o r d e p r e s s i o n . Seminal r e c e p t a c l e reduced i n s i z e ( 3 5 ) , o r i e n t e d t r a n s v e r s e l y ( 3 7 ) . Ovary e l o n g a t e , e n t i r e but not smooth, w i t h no e v i d e n c e of b i l o b e d s t r u c t u r e ( 3 6 ) . U t e r u s l a r g e , o c c u p y i n g more than 50% of t o t a l body w i d t h and more than 90% of t o t a l body l e n g t h . U t e r i n e duct n e i t h e r a t r o p h i e d nor d i l a t e d . S c h i z o c h o e r u s 1 i g u l o i d e u s ( D i e s i n g , 1850) Poche, 1922 ( f i g u r e 12) Monostoma 1 i q u l o i d e a D i e s i n g , 1850 ( p a r t i m ; o r i g i n a l d e s c r i p t i o n from Arapima g i g a s as V a s t r e s c u v i e r i , B r a z i l ) . A m p h i l i n a l i q u l o i d e a M o n t i c e l l i , 1892: 1-11, p i . 34, 35 ( r e d e s c r i p t i o n ; new c o m b i n a t i o n ) . S c h i z o c h o e r u s l i g u l o i d e u s Poche, 1922: 285-285 (new c o m b i n a t i o n ) ; S c h i z o c h o e r u s l i g u l o i d e u s : Poche, 1925: 256-338, f i g s . 7-16, p i . 2-7 ( s u p p l e m e n t a l m o r p h o l o g i c a l i n f o r m a t i o n ) : Fuhrmann, 1931: 106 ( l i s t e d ) ; Yamaguti, 1959: 13, p i . 6, f i g . 40 ( l i s t e d ) ; Joyeux and Baer, 1961: 345-346 ( l i s t e d ) ; Donges and H a r d e r , 1966: 138 ( l i s t e d ) ; D u b i n i n a , 1982: 83-91, f i g s . 11, 20, 21, 47-51 ( s u p p l e m e n t a l m o r p h o l o g i c a l i n f o r m a t i o n ) . Specimens examined: BMNH # 1927.5.27.105-124 H o s t s : Arapaima g i g a s C u v i e r ( T e l e o s t e i : O s t e o g l o s s i f o r m e s ) . 36 L o c a l i t i e s : N o r t h e r n B r a z i l Taxonomic c h a r a c t e r i s t i c s : Body e l o n g a t e , 49-54 mm l o n g and 3-4 mm wide. Tegument c o v e r e d w i t h r i d g e s forming c o n c e n t r i c a n n u l a t i o n s , over most or a l l of body s u r f a c e ( 3 8 ) . V a g i n a b i f u r c a t e ( 3 9 ) , opening t o both s u r f a c e s of the body near the p o s t e r i o r end. V a g i n a e l o n g a t e , e x t e n d i n g beyond the a n t e r i o r end of the ovary ( 4 0 ) . A n t e r i o r end of s e m i n a l r e c e p t a c l e g i v i n g r i s e t o l o n g t u b u l a r a c c e s s o r y s e m i n a l r e c e p t a c l e w i t h p e r i o d i c d i l a t i o n s , e x t e n d i n g a n t e r i o r l y t o a p p r o x i m a t e l y 1/3 t o t a l body l e n g t h ( 4 4 ) . U t e r u s N--shaped, a t r o p h i e d , w i t h a n t e r i o r and p o s t e r i o r t u r n s l o c a t e d w e l l away from the ends of t h e body; c o i l i n g of the u t e r i n e tube reduced ( 4 1 ) . Descending l i m b of N-shaped u t e r u s l o c a t e d next t o t e r m i n a l l i m b ( 4 2 ) . V i t e l l a r i a p o o r l y d e v e l o p e d , i n narrow bands w i t h t u b u l a r appearance (43 ) . Remarks: D i e s i n g ' s o r i g i n a l d e s c r i p t i o n of Monostoma 1 i g u l o i d e a appears t o be based on a mixed c o l l e c t i o n of S c h i z o c h o e r u s  1 i g u l o i d e u s and S c h i z o c h o e r u s j a n i c k i i . M o n t i c e l l i (1892) p r o v i d e d an unambiguous d e s c r i p t i o n of S c h i z o c h o e r u s  l i g u l o i d e u s , and J a n i c k i (1908) p r o v i d e d a s i m i l a r d e s c r i p t i o n of S c h i z o c h o e r u s j a n i c k i i , b o t h r e d e s c r i p t i o n s a p p e a r i n g under the name A m p h i l i n a l i g u l o i d e a . Poche (1922) r e c o g n i z e d t h a t two s p e c i e s were p r e s e n t i n Arapima g i g a s , and r e d e s c r i b e d these as S c h i z o c h o e r u s l i g u l o i d e u s and N e s o l e c i t h u s j a n i c k i i , r e s p e c t i v e l y . 37 S c h i z o c h o e r u s j a n i c k i i (Poche, 1922) comb, n. ( f i g u r e 13) Monostoma l i g u l o i d e u m D i e s i n g , 1850 ( p a r t i m ; o r i g i n a l d e s c r i p t i o n from Arapaima g i g a s as V a s t r e s c u v i e r i ) . A m p h i l i n a l i q u l o i d e a : J a n i c k i , 1908: 568-597, p i . 34,35 ( s u p p l e m e n t a l m o r p h o l o g i c a l i n f o r m a t i o n ) . N e s o l e c i t h u s j a n i c k i i Poche, 1922: 282-285; ( s u p p l e m e n t a l m o r p h o l o g i c a l i n f o r m a t i o n ) ; Fuhrmann, 1931: 160, f i g s . 190-192 ( l i s t e d ) ; Yamaguti, 1959: 14, p i . 16 f i g . 124 ( l i s t e d ) ; J o yeux - and Baer, 1961: 346, f i g s . 241,245 ( l i s t e d ) ; Donges and Ha r d e r , 1966: 138, ( l i s t e d ) ; D u b i n i n a , 1982: 91-97, f i g s . 15, 16, 23, 29, 52-54 ( s u p p l e m e n t a l m o r p h o l o g i c a l i n f o r m a t i o n ) . Specimens examined: MNHU #6627; BMNH #1980.4.15.1-2 u n f o r t u n a t e l y i t was not p o s s i b l e t o examine s t a i n e d and mounted specimens. H o s t s : Arapaima g i g a s C u v i e r ( T e l e o s t e i : O s t e o g l o s s i f o r m e s ) L o c a l i t i e s : n o r t h e r n and c e n t r a l B r a z i l . Taxonomic c h a r a c t e r i s t i c s : S c h i z o c h o e r u s w i t h f u s i f o r m body (4 5 ) , 76-78 mm i n l e n g t h , w i t h an average w i d t h of 21 mm. Tegument w i t h r i d g e s f o r m i n g c o n c e n t r i c a n n u l a t i o n s ( 3 8 ) . Te s t e s u n p a i r e d ( 4 6 ) . V a g i n a b i f u r c a t e , c o i l e d , opening t o both 38 s u r f a c e s of the body near t h e p o s t e r i o r end ( 3 9 ) . Seminal r e c e p t a c l e l a r g e but w i t h o u t e x t e n s i o n s , o c c u p y i n g much l e s s than 1/3 t o t a l body l e n g t h . U t e r u s N — s h a p e d , a t r o p h i e d , w i t h a n t e r i o r and p o s t e r i o r t u r n s l o c a t e d w e l l away from the ends of the body; c o i l i n g of u t e r i n e tube reduced ( 4 1 ) . Descending l i m b of N-shaped u t e r u s a d j a c e n t t o t e r m i n a l l i m b ( 4 2 ) . V i t e l l a r i a p o o r l y d e v e l o p e d , f o r m i n g narrow l a t e r a l bands w i t h t u b u l a r appearance ( 4 3 ) . Remarks: see comments on S c h i z o c h o e r u s l i g u l o i d e u s . S c h i z o c h o e r u s a f r i c a n u s (Donges and Harder) 1966, comb, n. ( f i g u r e 14) N e s o l e c i t h u s a f r i c a n u s Donges and Ha r d e r , 1966: 125-141, f i g s . 1-5 ( o r i g i n a l d e s c r i p t i o n from Gymnarchus n i l o t i c u s i n N i g e r i a ) . N e s o l e c i t h u s a f r i c a n u s : D u b i n i n a , 1982: 97-102, f i g s 55-58. Specimens examined: BMNH #1961.2.21.13-16; u n f o r t u n a t e l y no s t a i n e d specimens were a v a i l a b l e . Host: Gymnarchus n i l o t i c u s C u v i e r ( T e l e o s t e i : M o r m y r i f o r m e s ) . L o c a l i t i e s : Yewa R i v e r , southwest N i g e r i a Taxonomic c h a r a c t e r i s t i c s : S c h i z o c h o e r u s w i t h f u s i f o r m body shape ( 4 5 ) , 22-40 mm i n l e n g t h , w i d t h 11-20 mm. Tegument a n n u l a t e d ( 3 8 ) . V a g i n a b i f u r c a t e , c o i l e d , o p e n i n g t o both s u r f a c e s of the body near t h e p o s t e r i o r end ( 3 9 ) . Vag i n a 39 e l o n g a t e , e x t e n d i n g a n t e r i o r t o a n t e r i o r margin of ovary ( 4 0 ) . Seminal r e c e p t a c l e l a r g e , but w i t h o u t e x t e n s i o n s , o c c u p y i n g much l e s s than 1/3 of t o t a l body l e n g t h . U t e r u s N — s h a p e d , a t r o p h i e d , w i t h a n t e r i o r and p o s t e r i o r t u r n s l o c a t e d w e l l away from the ends of the body; c o i l i n g of u t e r i n e tube reduced ( 4 1 ) . Descending l i m b of N-shaped u t e r u s l o c a t e d a d j a c e n t t o t e r m i n a l l i m b ( 4 2 ) . V i t e l l a r i a p o o r l y d e v e l o p e d , f o r m i n g narrow l a t e r a l bands w i t h t u b u l a r appearance ( 4 3 ) . G i g a n t o l i n a Poche, 1922 S c h i z o c h o e r i d a e w i t h f i r s t a s c e n d i n g and d e s c e n d i n g l i m b s l a t e r a l , t e r m i n a l l i m b median ( l o o p e d ; 18). U t e r i n e d uct d i l a t e d ( 1 9 ) . Vas d e f e r e n s not c o i l e d ( 2 0 ) . P a r a s i t e s of p e r c i f o r m f i s h e s and t u r t l e s . A u s t r a l i a , I n d o - P a c i f i c . Type s p e c i e s : G i g a n t o l i n a magna ( S o u t h w e l l , 1915). G i g a n t o l i n a magna ( S o u t h w e l l , 1915) ( f i g u r e 16) A m p h i l i n a magna S o u t h w e l l , 1912: 259-278 ( l i s t e d ; not named); S o u t h w e l l , 1915: 311-330 ( o r i g i n a l d e s c r i p t i o n from P l e c t o r h y n c h u s n i g r a as Diagramma c r a s s i s p i n u m , S r i L a n k a ) ; S o u t h w e l l , 1928: 322-324, f i g s . 1,2 ( l i s t e d ) . G i q a n t o l i n a magna Poche, 1922: 281-282 (new c o m b i n a t i o n ) ; Poche, 1926b: 1-27, f i g s . 1-16 ( r e d e s c r i p t i o n ) ; 40 G i g a n t o l i n a magna: Fuhrmann, 1931: 160, f i g . 181 ( l i s t e d ) ; Wardle and McLeod, 1952: 658, f i g . 416 ( l i s t e d ) ; Yamaguti, 1959: 12, p i . 16 f i g . 128 ( l i s t e d ) ; Joyeux and Baer, 1961: 346, f i g . 242, ( l i s t e d ) ; Donges and H a r d e r , 1966: 138 ( l i s t e d ) ; D u b i n i n a , 1982: 113-123, f i g s . 14, 65-73 ( s u p p l e m e n t a l m o r p h o l o g i c a l i n f o r m a t i o n ) . Gyrometra a l b o t a e n i a Yamaguti, 1954: 367-373, f i g s . 13,14 ( d e s c r i p t i o n from P l e c t o r h y n c h u s sp. as Diagramma s p . ) ; Donges and H a r d e r , 1966: 138 ( l i s t e d ) . Gyrometra kunduchi K h a l i l , 1977: 15-19, f i g s . 1-3, p i . 1 ( d e s c r i p t i o n from P l e c t o r h y n c h u s p i c t a . Specimen examined: BMNH #1934.4.23.47 ( h o l o t y p e a l s o examined by D.R. B r o o k s ) ; MPM # 22164 H o s t s : P l e c t o r h y n c h u s n i g r u s C u v i e r , P. p i c t a Thunberg. L o c a l i t i e s : S r i Lanka, Malay P e n n i n s u l a , C e l e b e s , Tanzanian C o a s t . Taxonomic c h a r a c t e r i s t i c s : G i g a n t o l i n a w i t h e l o n g a t e body; body l e n g t h 130-380 mm, w i d t h 11mm. P o s t e r i o r margin w i t h l a r g e p a p i l l a s i t u a t e d i n median d e p r e s s i o n t h r o u g h which the male pore opens ( 2 0 ) . Ovary b i l o b e d , s y m m e t r i c a l and f i n e l y l o b a t e ( 2 2 ) . Ovary r o t a t e d under s e m i n a l r e c e p t a c l e ( 2 3 ) . Vagina s h o r t , opening t o s u r f a c e t h r o u g h muscular pore ( 2 1 ) . Seminal r e c e p t a c l e w i t h e x t e n s i o n ( 2 4 ) . Ductus y a m a g u t i i p r e s e n t , 41 e x t e n d i n g from the s e m i n a l r e c e p t a c l e t o the a p i c a l i n v a g i n a t i o n i n s i n u o u s c o i l s on the v e n t r a l s i d e of the u t e r u s ( 2 5 ) . Remarks: Yamaguti (1954) noted t h a t the major d i f f e r e n c e between G i g a n t o l i n a magna and Gyrometra a l b o t a e n i a was the c o n f o r m a t i o n of the u t e r u s . S o u t h w e l l ' s o r i g i n a l d e s c r i p t i o n appears t o be i n c o r r e c t , and Poche's (1925) r e d e s c r i p t i o n i s based on e x a m i n a t i o n of the p o s t e r i o r end o n l y . Joyeux and Baer (1961) were the f i r s t t o r e c o g n i z e the synonymy, and t h i s has been c o n f i r m e d by D u b i n i n a (1982). E x a m i n a t i o n of the h o l o t y p e of G i g a n t o l i n a magna i n the B r i t i s h Museum c o n f i r m e d the o b s e r v a t i o n s of Joyeux and Baer (1961) and D u b i n i n a (1982). G i g a n t o l i n a e l o n g a t a ( J o h n s t o n , 1931) comb, n. ( f i g u r e 15) A u s t r a m p h i l i n a e l o n g a t a J o h n s t o n , 1931: 1-7, f i g s . 1-9 ( o r i g i n a l d e s c r i p t i o n from C h e l o d i n a l o n g i c o l l i s , New South W a l e s ) ; A u s t r a m p h i l i n a e l o n g a t a : Yamaguti, (1954): ( l i s t e d ) ; Yamaguti, 1959: 168-169, p i . 26 f i g . 200 ( l i s t e d ) ; Joyeux and Baer, 1961: 346 ( l i s t e d ) ; Donges and H a r d e r , 1966: 138 ( l i s t e d ) ; Wardle and McLeod, 1952: 368 ( l i s t e d ) ; D u b i n i n a , 1982: 102-113, f i g s . 24, 59-64 (supp l e m e n t a r y m o r p h o l o g i c a l i n f o r m a t i o n ) ; Rohde and G e o r g i , 1983: (supplementary m o r p h o l o g i c a l i n f o r m a t i o n ) . K o s t e r i n a k u i p e r i I h l e and I h l e - L a n d e n b e r g , 1932: 309-316, 42 f i g s . 1-10 ( d e s c r i p t i o n from C h e l o d i n a l o n g i c o l l i s , A u s t r a l i a ) . Specimens examined: BMNH #1982.10.20.8, MNHN #204, AM #2784 ( h o l o t y p e ) ; a d d i t i o n a l specimens p r o v i d e d by Dr. K l a u s Rohde, U n i v e r s i t y of New En g l a n d , A u s t r a l i a . H o s t: C h e l o d i n a l o n g i c o l l i s Shaw ( T e t r a p o d a : C h e l o n i a ) L o c a l i t y : New South Wales Taxonomic c h a r a c t e r i s t i c s : G i g a n t o l i n a w i t h e l o n g a t e body 58-68 mm l o n g and 7-13 mm wide. P o s t e r i o r end w i t h median d e p r e s s i o n . E j a c u l a t o r y duct u n i t i n g w i t h v a g i n a t o form g e n i t a l a t r i u m ( 2 6 ) . V a g i n a l i n e d w i t h s p i n e s f o r h a l f of l e n g t h . Seminal duct d i l a t e d , f o r m i n g a c c e s s o r y s e m i n a l r e c e p t a c l e ( 2 7 ) . T e r m i n a l l i m b of u t e r u s w i t h pronounced metraterm. KEY TO THE SPECIES OF THE SUPERORDER AMPHILINIPEA 1a. U t e r u s N-shaped 2 1b. U t e r u s l o o p e d 7 2a. Body not e l o n g a t e ; e l l i p t i c a l or f u s i f o r m 3 2b. Body e l o n g a t e 6 43 3a. Body e l l i p t i c a l , v a g i n a c r o s s i n g male duct 4 3b. Body f u s i f o r m , v a g i n a not c r o s s i n g male duct 5 4a. T e s t e s s c a t t e r e d , male duct c r o s s i n g v a g i n a p r o x i m a l t o e j a c u l a t o r y b u l b A m p h i l i n a f o l i a c e a 4b. T e s t e s p a r t i a l l l y d i s r u p t e d , male duct c r o s s i n g v a g i n a d i s t a l t o e j a c u l a t o r y b u l b A_^  j a p o n i c a 5a. Body l e s s than 40 mm i n l e n g t h , t e s t e s i n p a i r s S_^  a f r i c a n u s 5b. Body more than 40 mm i n l e n g t h , t e s t e s not p a i r e d S. j a n i c k i i 6a. V a g i n a s i n g l e S c h i z o c h o e r u s paragonopora 6b. Vagina double S_^  1 i g u l o i d e u s 7a. Ovary b i l o b e d , g e n i t a l p o r e s s e p a r a t e . . G i g a n t o l i n a magna 7b. Ovary ki d n e y - s h a p e d , g e n i t a l p o r e s common G. e l o n g a t a SPECIES INQUIRENDAE S p e c i e s of q u e s t i o n a b l e v a l i d i t y a t the moment a r e A m p h i l i n a b i p u n c t a t a ( R i s e r , 1948), G i g a n t o l i n a a l b o t a e n i a (Yamaguti, 1954) and G i g a n t o l i n a kunduchi ( K h a l i l , 1977). R i s e r l i s t e d t he f o l l o w i n g d i f f e r e n c e s between Amphi1ina  j a p o n i c a and A. b i p u n c t a t a : the s i z e and shape of t h e t e s t e s and o v a r y , the s i z e of the a p i c a l o r g a n , the s i z e of the e j a c u l a t o r y b u l b , and the p r e s e n c e i n A m p h i l i n a j a p o n i c a of unbroken v i t e l l i n e masses. The s i n g l e t ype specimen of 44 A m p h i l i n a j a p o n i c a i s l a r g e r than most of the specimens c o l l e c t e d on the P a c i f i c Coast of N o r t h A m e r i c a , a l t h o u g h a s i n g l e specimen of comparable s i z e was examined d u r i n g the c o u r s e of t h i s s t u d y . Specimens l a b e l l e d A. b i p u n c t a t a R i s e r , 1948 e x i b i t e d c o n s i d e r a b l e v a r i a b i l i t y i n the r e l a t i v e s i z e of body s t r u c t u r e s . C o n s e q u e n t l y , a l l o m e t r i c growth would seem t o be a p l a u s i b l e e x p l a n a t i o n f o r t h e d i f f e r e n c e s o b s e r v e d . Unbroken v i t e l l i n e masses are o b s e r v e d i n some Nort American specimens as w e l l . As f o r the G i q a n t o l i n a s p e c i e s , Yamaguti (1954) noted t h a t the major d i s t i n g u i s h i n g f e a t u r e between h i s G. a l b o t a e n i a and G. magna i s the u t e r i n e c o n f i g u r a t i o n . However, a c c o r d i n g t o Joyeux and Baer (1961), D u b i n i n a (1982), and the r e s u l t s of t h i s i n v e s t i g a t i o n , the u t e r u s i s c l e a r l y l o o p e d r a t h e r N-shaped. The s o u r c e of the c o n f u s i o n s u r r o u n d i n g such a l a r g e and o b v i o u s s t r u c t u r e i s p r o b a b l y Poche's (1926) r e d e s c r i p t i o n of G. magna, which i s based on the e x a m i n a t i o n of t h e p o s t e r i o r h a l v e s of two speclmens. D i f f e r e n c e s between Gyrometra a l b o t a e n i a and G. kunduchi noted by K h a l i l (1977) i n c l u d e the p r e s e n c e i n G. kunduchi of unbroken v i t e l l i n e masses, the absence of an a p i c a l i n v a g i n a t i o n w i t h the concommittant opening of the u t e r u s and d u c t u s y a m g u t i i on the body s u r f a c e . W i t h the t i g h t p a c k i n g of the v i t e l l a r i a o b s e r v e d i n t h i s s p e c i e s anastomosing v i t e l l i n e d u c t s a r e e x t r e m e l y d i f f i c u l t t o f i n d . S i n c e a l l a m p h i l i n i d s appear t o have a pharynx c a p a b l e of some degree of e v e r s i o n and r e t r a c t i o n , the p o s i t i o n of the u t e r i n e pore and t h e r e f o r e of 45 t h e a p e r t u r e of the d u c t u s y a m a g u t i i w i l l v a r y w i t h t h e p o s i t i o n of the pharynx. R e p o r t e d d i f f e r e n c e s between G. a l b o t a e n i a and G. magna i n c l u d e the s i z e and prominence of the p o s t e r i o r p a p i l l a and the d i s t r i b u t i o n of the t e s t e s . With o n l y two specimens t o examine, t h e r e i s no way t o e s t i m a t e the v a r i a b i l i t y of t h e s e f e a t u r e s . DISCUSSION COEVOLUTION OF AMPHILINIDEAN PARASITES AND THEIR HOSTS The a s s o c i a t i o n s between a m p h i l i n i d e a n p l a t y h e l m i n t h s and t h e i r v e r t e b r a t e h o s t s have been examined u s i n g the methods of Brooks (1979, 1981; see a l s o M i t t e r and B r o o k s , 1983). These methods w i l l be d e s c r i b e d o n l y b r i e f l y h e r e . Symbionts may become a s s o c i a t e d w i t h each o t h e r e i t h e r t h r o u g h c o s p e c i a t i o n or through c o l o n i z a t i o n . A h y p o t h e s i s of c o e v o l u t i o n can be t e s t e d by the comparison of host and p a r a s i t e p h y l o g e n i e s . Congruence of h o s t and p a r a s i t e p h y l o g e n i e s c o r r o b o r a t e s a h y p o t h e s i s of c o s p e c i a t i o n . D e p a r t u r e s from h i s t o r i c a l a s s o c i a t i o n ( i n c o n g r u e n t p h y l o g e n i e s ) f a l s i f y a h y p o t h e s i s o f s t r i c t c o s p e c i a t i o n and i n d i c a t e t h a t some of the o b s e r v e d a s s o c i a t i o n s may be e x p l a i n e d more p a r s i m o n i o u s l y by h o s t t r a n s f e r s than by c o s p e c i a t i o n . The phylogeny of the a m p h i l i n i d s has been compared w i t h a c u r r e n t l y a c c e p t e d h y p o t h e s i s of h o s t r e l a t i o n s h i p , i n t h i s case 46 t h a t of Lauder and Liem (1983; see f i g . 18). The hos t and p a r a s i t e cladograms agree i n the placement of s i x out of e i g h t t a x a . A more r i g o r o u s comparison was made by c o n s t r u c t i n g a b i n a r y m a t r i x d e s c r i b i n g the r e l a t i o n s h i p s among the h o s t t a x a as p o s t u l a t e d by Lauder and Liem (see Appendix A, t a b l e I I ) . The t r a n s f o r m a t i o n s e r i e s c o m p r i s i n g the host p h y l o g e n e t i c t r e e were then mapped onto the p a r a s i t e phylogeny as e c o l o g i c a l c h a r a c t e r s (see f i g . 19). When t h e s e h o s t a s s o c i a t i o n c h a r a c t e r s a r e mapped onto the p a r a s i t e c ladogram a c o n s i s t e n c y i n d e x v a l u e of 70% (7/10) i s o b t a i n e d . T h i s i n d i c a t e s t h a t the p h y l o g e n e t i c r e l a t i o n s h i p s of a m p h i l i n i d e a n s a r e s t r o n g l y c o r r e l a t e d w i t h t h e p h y l o g e n e t i c r e l a t i o n s h i p s of t h e i r h o s t s and i m p l i e s t h a t the host a s s o c i a t i o n s can m o s t l y be a t t r i b u t e d t o h i s t o r i c a l a s s o c i a t i o n (see f i g . 2 0 ) . When so few s p e c i e s of such a l a r g e h o s t taxon a r e p a r a s i t i z e d , i t i s n e c e s s a r y t o q u e s t i o n whether i t i s l e g i t i m a t e t o a t t r i b u t e any of the observed a s s o c i a t i o n s t o c o e v o l u t i o n . I f the d i s t r i b u t i o n of the a m p h i l i n i d s i s owing t o c o l o n i z a t i o n r a t h e r than c o e v o l u t i o n , i t would seem u n l i k e l y t h a t t h e r e would be any degree of congruence w i t h the host p h ylogeny. C o e v o l u t i o n t h e r e f o r e r e p r e s e n t s the more p a r s i m o n i o u s a l t e r n a t i v e . What i s of i n t e r e s t , t h e n , i s e x p l a i n i n g how c o e v o l u t i o n c o u l d produce a s p o t t y host d i s t r i b u t i o n p a t t e r n . C l e a r l y such a p a t t e r n c o u l d be the r e s u l t of samp l i n g e r r o r . Many t e l e o s t s p e c i e s , e s p e c i a l l y i n t h e t r o p i c s , have 47 not been examined f o r p a r a s i t e s . However, the l a r g e s i z e of a m p h i l i n i d s and t h e i r l o c a t i o n i n the coelom make i t u n l i k e l y t h a t they have been o v e r l o o k e d . A l t h o u g h i t seems p o s s i b l e , even l i k e l y , t h a t more a m p h i l i n i d s c o u l d be d i s c o v e r e d , i t does not seem l i k e l y t h a t s u f f i c i e n t numbers w i l l be found t o e x p l a i n the h o s t d i s t r i b u t i o n of the a m p h i l i n i d s . A second e x p l a n a t i o n which c o u l d be g i v e n f o r a s p o t t y h o s t d i s t r i b u t i o n i s host e x t i n c t i o n w i t h concommittant p a r a s i t e e x t i n c t i o n . Many of the t e l e o s t groups i n c l u d e d i n the a n a l y s i s of Lauder and Liem (1983), e s p e c i a l l y t h o s e b r a n c h i n g o f f between the a c i p e n s e r i d s and the o s t e o g l o s s i d s , a r e now e x t i n c t . These f i s h e s t h e r e f o r e r e p r e s e n t c a n d i d a t e s f o r h o s t s of e x t i n c t a m p h i l i n i d s p e c i e s . G i v e n a s p o t t y d i s t r i b u t i o n among e x t a n t h o s t s , two e x p l a n a t i o n s f o r the absence of a p a r a s i t e a r e p o s s i b l e . The h o s t may be p h y s i o l o g i c a l l y s u s c e p t i b l e , but e x c l u d e d because of an e c o l o g i c a l s h i f t , i . e . the p a r a s i t e i s s i m p l y not e n c o u n t e r e d . A l t e r n a t i v e l y , the host may be e c o l o g i c a l l y s u s c e p t i b l e , but not p h y s i o l o g i c a l l y (or p h y s i c a l l y ) , so t h a t the h o s t may encounter the p a r a s i t e but i n f e c t i o n does not o c c u r . O b v i o u s l y , i t i s p o s s i b l e t h a t b o t h e c o l o g i c a l and p h y s i o l o g i c a l s h i f t s may o ccur s i m u l t a n e o u s l y . A p o s s i b l e e c o l o g i c a l l i m i t a t i o n may be i n f e r r e d from the f a c t t h a t a l l a m p h i l i n i d e a n s a r e found i n e i t h e r f r e s h w a t e r or e u r y h a l i n e h o s t s , and a p o s s i b l e p h y s i c a l c o n s t r a i n t i n l a r g e body s i z e . Thus, i t appears l i k e l y t h a t many host group s p e c i e s can be e l i m i n a t e d as p o t e n t i a l h o s t s f o r a m p h i l i n i d s because they a r e 48 m a r i n e , or they a r e as s m a l l as or s m a l l e r than known a m p h i l i n i d s . I t i s i n t e r e s t i n g t o note t h a t c e s t o d e s a r e found i n r e l a t i v e l y few t e l e o s t s , and many of the t e l e o s t h o s t s of c e s t o d e s a r e i n the same o r d e r s as the h o s t s of a m p h i l i n i d s : a c i p e n s e r i f o r m s , mormyriforms, s i l u r i f o r m s and p e r c i f o r m s . I t i s p o s s i b l e t h a t t h i s may r e f l e c t some u n d e r l y i n g common d i f f e r e n c e i n the e c o l o g i c a l or p h y s i o l o g i c a l s u s c e p t i b i l i t y of t h e s e h o s t s t o c e s t o i d e a n s (sensu Brooks e t a l . , 1985a). BIOGEOGRAPHY The b i o g e o g r a p h i c d i s t r i b u t i o n of the a m p h i l i n i d s has been s t u d i e d u s i n g the methods of v i c a r i a n c e biogeography (see N e l s o n and P l a t n i c k , 1981, 1984; C r a c r a f t , 1983; M i c k e v i c h , 1981; Rosen, 1978; W i l e y , 1981). Organisms may become a s s o c i a t e d w i t h p a r t i c u l a r g e o g r a p h i c l o c a t i o n s e i t h e r t h r o u g h v i c a r i a n c e ( p a s s i v e h i s t o r i c a l a s s o c i a t i o n ) or by d i s p e r s a l . There i s a d i r e c t c o r r e s p o n d e n c e between the way i n which organisms become a s s o c i a t e d w i t h new a r e a s and the way i n which symbionts become a s s o c i a t e d w i t h new h o s t s ( M i t t e r and B r o o k s , 1983). D i s p e r s a l s c e n a r i o s can be c o n s t r u c t e d t o e x p l a i n the a s s o c i a t i o n between any organism and the g e o g r a p h i c l o c a l i t y i t i n h a b i t s . T h e r e f o r e , t h e r e w i l l be no cause t o abandon an i n i t i a l h y p o t h e s i s of d i s p e r s a l . I f i n s t e a d the i n i t i a l h y p o t h e s i s i s v i c a r i a n c e , the h y p o t h e s i s may be s u b j e c t e d t o e m p i r i c a l 49 t e s t i n g . A h y p o t h e s i s of v i c a r i a n c e may be t e s t e d by comparing the phylogeny of t h e organism t o a h y p o t h e s i s of p h y l o g e n e t i c r e l a t i o n s h i p f o r t h e g e o g r a p h i c l o c a l i t i e s . The a r e a cladogram may be c o n s t r u c t e d from e i t h e r g e o l o g i c a l e v i d e n c e or b i o l o g i c a l e v i d e n c e , the l a t t e r c o n s i s t i n g of g e n e r a l i z e d t r a c k s or s h a r e d d i s t r i b u t i o n p a t t e r n s . The p r e s e n t day d i s t r i b u t i o n of the a m p h i l i n i d s i s shown i n the form of an a r e a c l a d o g r a m i n f i g u r e 21. I t i s p o s s i b l e i m m e d i a t e l y t o d i v i d e the a m p h i l i n i d s i n t o two g e o g r a p h i c groups, the S u b f a m i l y A m p h i l i n i n a e , o c c u r r i n g i n n o r t h temperate r e g i o n s , and the S u b f a m i l y S c h i z o c h o e r i n a e , o c c u r r i n g i n the t r o p i c s and s o u t h e r n hemisphere. I t i s g e n e r a l l y a g r e e d t h a t t h e s u p e r c o n t i n e n t Pangaea was d i v i d e d i n t o two c o n t i n e n t s by two r i f t s which opened up the A t l a n t i c and I n d i a n Oceans (see D i e t z and Holden, 1971 f o r a r e v i e w of t h i s s u b j e c t ) . L a u r a s i a and Gondwana, the two c o n t i n e n t s t h u s p r o d u c e d , then fragmented, L a u r a s i a g i v i n g r i s e t o N o r t h A m e r i c a , G r e e n l a n d and E u r a s i a , and Gondwana g i v i n g r i s e t o I n d i a , A f r i c a , South A m e r i c a , A u s t r a l i a and A n t a r c t i c a . The b i o g e o g r a p h i c d i s t r i b u t i o n shows a s t r o n g c o r r e l a t i o n w i t h hypotheses of r e l a t i o n s h i p f o r t h e a r e a s . I t i s c l e a r t h a t the d i v e r g e n c e of t h e A m p h i l i n i n a e and the S c h i z o c h o e r i n a e c o r r e s p o n d s t o t h e s e p a r a t i o n of t h e L a u r a s i a n and Gondwanian landmasses. W i t h i n t h e S u b f a m i l y A m p h i l i n i n a e , the d i v e r g e n c e of t h e two s p e c i e s c o r r e s p o n d s t o t h e s p l i t t i n g of E u r a s i a and N o r t h A m e r i c a . The p h y l o g e n e t i c r e l a t i o n s h i p s of the S u b f a m i l y 50 S c h i z o c h o e r i n a e a r e s t r o n g l y c o r r e l a t e d w i t h h i s t o r i c a l g e o l o g y . S p e c i e s of S c h i z o c h o e r u s a r e found i n I n d i a , A f r i c a , and South A m e r i c a , w h i l e s p e c i e s of G i g a n t o l i n a a r e found i n A u s t r a l i a and on i s l a n d s i n the I n d i a n Ocean. The d i s t r i b u t i o n of G i g a n t o l i n a magna appears p u z z l i n g a t f i r s t . Four c o l l e c t i o n s i t e s have been r e p o r t e d : S u l a w e s i , t h e Malay P e n n i n s u l a , S r i Lanka, and the c o a s t of T a n z a n i a . The geology of s o u t h e a s t A s i a i s complex and c o n t r o v e r s i a l (see A u d l e y - C h a r l e s , 1978 f o r a comprehensive r e v i e w of the h i s t o r i c a l g e o l o g y of t h i s r e g i o n ) . S u l a w e s i i s composed of two g e o l o g i c a l l y d i s t i n c t p o r t i o n s , one L a u s a s i a n and the o t h e r Gondwanian, w i t h the Gondwanian p o r t i o n b e i n g A u s t r a l i a n i n o r i g i n ( A u d l e y - C h a r l e s , 1978).' The Malay P e n n i n s u l a i s c l e a r l y L a u r a s i a n ( A u d l e y - C h a r l e s , 1978). S r i Lanka i s Gondwanian, and e x h i b i t s b i o g e o g r a p h i c l i n k s w i t h A u s t r a l i a ( A x e l r o d , 1972). I t i s u n f o r t u n a t e t h a t K h a l i l (1977) d i d not s p e c i f y the c o l l e c t i o n s i t e more p r e c i s e l y . There a r e , however, b i o g e o g r a p h i c l i n k s between Madagascar and A u s t r a l i a ( P a u l i a n , 1972). The d i s t r i b u t i o n of G i g a n t o l i n a magna becomes l e s s p u z z l i n g when the host i s c o n s i d e r e d . S p e c i e s of P l e c t o r h y n c h u s a r e e u r y h a l i n e , making marine d i s p e r s a l much more l i k e l y . F u r t h e r m o r e , the two host s p e c i e s a r e r e l a t i v e l y common i n A u s t r a l i a ( G r a n t , 1982). T h i s s p e c i e s a p p e a r s , t h e n , t o have o r i g i n a t e d i n E a s t Gondwana and w i l l be c o n s i d e r e d A u s t r a l i a n f o r the purposes of the b i o g e o g r a p h i c a n a l y s i s . G e o l o g i s t s a r e not i n agreement as t o t h e p r e c i s e arrangement of the c o n t i n e n t s w i t h i n Gondwana or of the t i m i n g 51 and o r d e r of the s p l i t , p a r t i c u l a r l y w i t h r e g a r d t o the s e p a r a t i o n of I n d i a . D i e t z and Holden (1971), f o r example, p o s t u l a t e a v e r y e a r l y s p l i t t i n g and l o n g p e r i o d of d r i f t i n g toward A s i a . C o l b e r t (1981), based on p a l e o n t o l o g i c a l e v i d e n c e , has proposed i n s t e a d t h a t a l t h o u g h r i f t i n g o c c u r r e d v e r y e a r l y , the c o n t i n e n t s remained i n c o n t a c t f o r a l o n g time a f t e r w a r d s w i t h a v e r y b r i e f p e r i o d of movement. S e v e r a l o t h e r b i o l o g i s t s (see G o s l i n e , 1972; C r a c r a f t , 1972) have a d v o c a t e d a l a t e r s e p a r a t i o n of I n d i a and A f r i c a . I t a p p e a r s , t h e n , t h a t t h e r e i s a c o n f l i c t between the b i o l o g i c a l e v i d e n c e and the g e o l o g i c a l e v i d e n c e . E x i s t i n g e v i d e n c e drawn from both the b i o l o g i c a l and the g e o l o g i c a l l i t e r a t u r e p o i n t s t o f o u r hypotheses of r e l a t i o n s h i p f o r the a r e a s i n q u e s t i o n ( f i g u r e 2 2 ) . The f i r s t of these ( f i g . 22a) i s based on the d i s t r i b u t i o n of f o s s i l t e t r a p o d s ( C o l b e r t , 1981), e x t a n t t e t r a p o d s ( C r a c r a f t , 1972) and e x t a n t f r e s h w a t e r f i s h ( G o s l i n e , 1972). The second ( f i g . 22c) was o b t a i n e d from Rosen (1978) and i s based on both g e o l o g i c a l and b i o l o g i c a l e v i d e n c e . The t h i r d a r e a cladogram ( f i g . 22e) i s based on the d i s t r i b u t i o n s of f o s s i l ammonites (Thomson, 1981) and e x t a n t marine i s o p o d s (taken from B r u s c a , 1984). The l a s t h y p o t h e s i s of a r e a r e l a t i o n s h i p i s based on D i e t z and Holden (1971). These f o u r cladograms have been c o n v e r t e d i n t o b i n a r y m a t r i c e s and. mapped onto the h y p o t h e s i s of p h y l o g e n e t i c r e l a t i o n s h i p f o r the a m p h i l i n i d s (see f i g s . 22b, d, f , h; T a b l e s I I I - V I , Appendix A ) . An e x c e l l e n t f i t was o b t a i n e d w i t h a l l f o u r a r e a 52 c l a d ograms, i n d i c a t i n g t h a t v i c a r i a n c e i s c l e a r l y the b e s t e x p l a n a t i o n f o r the d i s t r i b u t i o n . The h y p o t h e s i s of p h y l o g e n e t i c r e l a t i o n s h i p f o r the a m p h i l i n i d s was found t o be c o m p l e t e l y congruent w i t h the a r e a c ladogram based on v e r t e b r a t e d i s t r i b u t i o n s ( f i g . 22a). A c o n s i s t e n c y index of 88.9% was o b t a i n e d f o r the a r e a cladogram o b t a i n e d from Rosen (1978), i n d i c a t i n g t h a t the f i t of the a m p h i l i n i d d a t a t o t h i s h y p o t h e s i s of area r e l a t i o n s h i p i s a l s o good. The c o n s i s t e n c y index o b t a i n e d f o r the two r e m a i n i n g a r e a cladograms was 87.5%. The p o o r e r f i t of the a r e a cladogram based on the d i s t r i b u t i o n s of marine i n v e r t e b r a t e s i s not unexpected. S i m i l a r l y , i t i s not s u r p r i s i n g t h a t a b e t t e r f i t i s o b t a i n e d w i t h the a r e a cladograms based on v e r t e b r a t e d i s t r i b u t i o n s , c o n s i d e r i n g t h a t a m p h i l i n i d s are p a r a s i t e s of v e r t e b r a t e s . In f a c t , the complete congruence of the a m p h i l i n i d d i s t r i b u t i o n s w i t h an a r e a cladogram based on the d i s t r i b u t i o n s of f r e s h w a t e r f i s h e s (from G o s l i n e , 1972) p r o v i d e s independent c o r r o b o r a t i o n f o r the h y p o t h e s i s t h a t the a m p h i l i n i d s c o e v o l v e d w i t h f r e s h w a t e r t e l e o s t s . I t i s somewhat more d i f f i c u l t t o e x p l a i n why the f i t of the a r e a cladograms based on g e o l o g i c a l e v i d e n c e i s a l s o not as good. Rosen (1978) and Craw and Weston (1984) have advocated u s i n g b i o g e o g r a p h i c e v i d e n c e t o c h a l l e n g e g e o l o g i c a l t h e o r i e s ; t h i s i s perhaps an o p p o r t u n i t y t o do so. A l t e r n a t i v e l y , s i n c e t h e f i t of t h e a m p h i l i n i d d i s t r i b u t i o n t o the g e o l o g i c a l h y p otheses i s n o n e t h e l e s s s t i l l good, the b e t t e r f i t o b t a i n e d w i t h the a r e a cladograms based on v e r t e b r a t e d i s t r i b u t i o n s may 53 s i m p l y r e f l e c t an i n h e r e n t l i m i t a t i o n on the e x t e n t t o which b i o l o g i c a l p a t t e r n s can be used t o i n f e r g e o l o g i c a l p r o c e s s e s . 54 I I I . PHYLOGENETIC ANALYSIS OF THE GYROCOTYLIDEA  INTRODUCTION The g y r o c o t y l i d e a n s a r e a s m a l l group of f l a t w o r m s p a r a s i t i z i n g the s p i r a l v a l v e of h o l o c e p h a l a n f i s h e s . They a r e c h a r a c t e r i z e d by the p r e s e n c e of a f u n n e l - s h a p e d a d h e s i v e organ, or r o s e t t e . G y r o c o t y l i d e a n s a r e c o n s i d e r e d t o be the s i s t e r group of the c e s t o i d e a n s , or a m p h i l i n i d e a n s p l u s t r u e tapeworms. T o g e t h e r , t h e c e s t o i d e a n s and g y r o c o t y l i d e a n s c o m p r i s e the C e s t o d a r i a (sensu Brooks e t a _ l . , 1985a). C e s t o d a r i a n s have i n common a r e t i c u l a t e e x c r e t o r y system, the absence of the gut and the l o s s of t h e cercomer i n development. G y r o c o t y l i d e a n s a l s o s u p e r f i c i a l l y resemble monogeneans i n the a n t e r i o r l o c a t i o n of the e x c r e t o r y pores and the p r e s e n c e of a p o s t e r i o r a d h e s i v e o rgan. Because of t h e s e s i m i l a r i t i e s the g y r o c o t y l i d s have sometimes been p l a c e d w i t h the monogeneans (see L l w e l l y n , 1965; Bychowsky, 1957). E a r l y w o r k e r s , however found the p o s i t i o n of the g y r o c o t y l i d e a n s even more e n i g m a t i c , and the g y r o c o t y l i d e a n s have at t i m e s been p l a c e d w i t h the h i r u d i n e a n s and nemerteans (see Watson, 1911 f o r a r e v i e w of the e a r l y work on the g y r o c o t y l i d e a n s ) . I t i s l i k e l y t h a t the c o n f u s i o n s u r r o u n d i n g the placement of the g y r o c o t y l i d s stems a t l e a s t i n p a r t from the e a r l y d e s c r i p t i o n s , which were vague and o f t e n c o n f l i c t i n g . The type s p e c i e s , G y r o c o t y l e rugosa D i e s i n g , 1850, was supposedly o b t a i n e d from a South A f r i c a n u n g u l a t e . The second s p e c i e s t o be d i s c o v e r e d , G y r o c o t y l e u r n a , was f i r s t d e s c r i b e d by K r o y e r 55 (1852), who gave i t the name C r o b y l o p h o r u s c h i m a e r i and l i s t e d a l a m e l l i b r a n c h m o l l u s c as the h o s t . K r o y e r ' s d e s c r i p t i o n has not been w i d e l y r e c o g n i z e d , and the name C r o b y l o p h o r u s c h i m a e r i has been s u p p r e s s e d (van der Land, 1967). In a second independent d e s c r i p t i o n of the same s p e c i e s (Wagener, 1852), t h i s time under the name Amphiptyches u r n a , the h o s t was r e p o r t e d t o be Chimaera  monstrosa, a h o l o c e p h a l a n f i s h . Amphiptyches was synonomized w i t h G y r o c o t y l e by Wagener (1858; i n Watson, 1911). The c o r r e c t i d e n t i t y of the h o s t s of g y r o c o t y l i d e a n s was not e s t a b l i s h e d u n t i l 1889, when M o n t i c e l l i p u b l i s h e d a r e p o r t of the type s p e c i e s , G y r o c o t y l e r u g o s a , from C a l l o r h i n c h u s c a l l o r h y n c h u s , a h o l o c e p h a l a n o c c u r r i n g i n the s o u t h e r n hemisphere. In s p i t e of M o n t i c e l l i ' s r e p o r t , t h r e e more unusual h o s t s were r e p o r t e d : a sheep (von L i n s t o w , 1901), a j e l l y f i s h (von L i n s t o w , 1903) and a second l a m e l l i b r a n c h ( S c o t t , 1911). The f i r s t has g e n e r a l l y been d i s c o u n t e d , w h i l e the l a t t e r two have p e r m i t t e d some a u t h o r s t o e n t e r t a i n the i d e a t h a t g y r o c o t y l i d s may have an i n d i r e c t l i f e c y c l e (see C o l e , 1968). D u r i n g the l a t e n i n e t e e n t h and e a r l y t w e n t i e t h c e n t u r i e s , a number of i n v e s t i g a t o r s a t t e m p t e d t o c l a r i f y the r e l a t i o n s h i p of the g y r o c o t y l i d s t o o t h e r p a r a s i t i c p l a t y h e l m i n t h s by t r y i n g t o r e c o g n i z e m o r p h o l o g i c a l homologies shared w i t h o t h e r p l a t y h e l m i n t h s (see Spencer, 1889; Lonnberg, 1891; K o f o i d and Watson, 1910; Watson, 1911; Ward, 1912; D o l l f u s , 1922; Fuhrmann, 1931; Wardle, 1932; R u s z k o w s k i , 1932). A major o b s t a c l e i n r e c o g n i z i n g the s y s t e m a t i c p o s i t i o n of the g y r o c o t y l i d e a n s was i d e n t i f y i n g the a n t e r i o r end of the body. The g y r o c o t y l i d 56 a d h e s i v e organ i s unique among the p l a t y h e l m i n t h s , showing o n l y a s l i g h t resemblance t o t h e o p i s t h a p t o r of p o l y o p i s t h o c o t y l e a n monogeneans. At the a n t e r i o r end i s a m u s c u l a r i n v a g i n a t i o n thought t o be a v e s t i g i a l pharynx (Brooks e t aJL. , 1985a). S i n c e the a p i c a l i n v a g i n a t i o n i s not a s s o c i a t e d w i t h a g u t , i t i n i t i a l l y p r o v i d e d l i t t l e h e l p i n i d e n t i f y i n g t h e a n t e r i o r end. The a n a t o m i c a l t e r m i n o l o g y employed i n e a r l y d e s c r i p t i o n s r e f l e c t s the u n c e r t a i n t y as t o the o r i e n t a t i o n of t h e s e o r g anisms. An e a r l y i n v e s t i g a t i o n of the h i s t o l o g y of the g y r o c o t y l i d nervous system (Watson, 1911) p l a c e d double t r a n s v e r s e nervous commissures a t both ends of t h e body. K o f o i d and Watson (1910) argued on t h i s b a s i s t h a t the r o s e t t e of g y r o c o t y l i d s , a l t h o u g h p o s t e r i o r , i s homologous w i t h the s c o l e x of c e s t o d e s . The q u e s t i o n of o r i e n t a t i o n was s e t t l e d , however, by the d e v e l o p m e n t a l s t u d y of R u s z k o w s k i (1932), who demonstrated t h a t the r o s e t t e d e v e l o p s from t h e cercomer. I c o n s i d e r ten of the t h i r t e e n d e s c r i b e d s p e c i e s t o be v a l i d . G y r o c o t y l e and G y r o c o t y l o i d e s have t r a d i t i o n a l l y been r e c o g n i z e d (see Fuhrmann, 1931; Wardle and McLeod, 1952; van der Land and D i e n s k e , 1968) a l t h o u g h Joyeux and Baer (1951, 1961) a l s o r e c o g n i z e d a t h i r d genus, Amphiptyches. L i t t l e attempt has been made t o r e c o n s t r u c t the p h y l o g e n e t i c r e l a t i o n s h i p s of the g y r o c o t y l i d s . E f f o r t s t o i n t e r p r e t or s y n t h e s i z e the i n f o r m a t i o n i n the o r i g i n a l d e s c r i p t i o n s have been concerned p r i m a r i l y w i t h a s s e s s i n g t h e v a l i d i t y of d e s c r i b e d s p e c i e s . G y r o c o t y l i d e a n p a r a s i t e s have been r e c o r d e d from seven h o l o c e p h a l a n s p e c i e s i n f o u r genera. F i v e of t h e s e h o s t s p e c i e s 57 a r e r e p o r t e d t o h a r b o r two g y r o c o t y l i d s p e c i e s . Of the r e m a i n i n g two host s p e c i e s , t h r e e g y r o c o t y l i d s p e c i e s have been d e s c r i b e d from Chimaera monstrosa and a s i n g l e s p e c i e s has been r e p o r t e d from H y d r o l a g u s o g i l b y i . The p r e s e n c e of more than one g y r o c o t y l i d s p e c i e s i n n e a r l y a l l of the host s p e c i e s examined has been a major source of the c o n f u s i o n s u r r o u n d i n g the number of v a l i d s p e c i e s . G y r o c o t y l i d e a n s a r e e a s i l y damaged i n p r e s e r v a t i o n , and the debate over the number of v a l i d s p e c i e s a l s o stems from q u e s t i o n s of j u s t how much d i s t o r t i o n can occur i n p r e s e r v a t i o n . Watson (1 9 1 1 ) , f o r example, a s s e r t e d t h a t the absence of e l a b o r a t e l y p l i c a t e d margins i n G y r o c o t y l e rugosa i s because of the d i s i n t e g r a t i o n of the specimens p r i o r t o p r e s e r v a t i o n . She may have been c o n f u s e d by Spencer's (1889) d e s c r i p t i o n of " G y r o c o t y l e u r n a " from C a l l o r h i n c h u s i n A u s t r a l i a n w a t e r s , which i s c l e a r l y d e s c r i b e d from a mixed c o l l e c t i o n (see Lynch, 1945) S i m i l a r l y , a c c o r d i n g t o Lynch (1945), b l a c k tegumental s p i n e s a r e o b s e r v e d o n l y when the gut c o n t e n t s of the host a r e a l l o w e d t o p u t r e f y . However, Simmons and L a u r i e (1972) r e p o r t o b s e r v i n g b l a c k s p i n e s i n g y r o c o t y l i d s c o l l e c t e d from f r e s h l y k i l l e d h o s t s . The g y r o c o t y l i d body i s a l s o e x t r e m e l y m u s c u l a r . Lynch (1945) d e s c r i b e d G y r o c o t y l e as "not o n l y h i g h l y c o n t r a c t i l e and e x t e n s i l e , but a l s o g i f t e d c o n t o r t i o n i s t s " whose most c o n s p i c u o u s m o r p h o l o g i c a l f e a t u r e s "are not amenable t o c o n v i n c i n g d e s c r i p t i o n . " Ward (1912), D o l l f u s (1922), and Wardle (1932) doubted the e x i s t e n c e of two g y r o c o t y l i d s p e c i e s 58 p a r a s i t i z i n g H y d r o l a g u s c o l l i e i , and c o n s i d e r e d a l l specimens t o be G y r o c o t y l e urna i d e n t i c a l t o G y r o c o t y l e urna from Chimaera  m o n s t r o s a . As Lynch (1945) n o t e d , some of t h e s e a u t h o r s p r o b a b l y d i d not have a c c e s s t o specimens of b o t h P a c i f i c s p e c i e s , a l t h o u g h Wardle (1932; see a l s o Wardle and MacLeod, 1952) i n c l u d e s a photograph c l e a r l y d i s p l a y i n g both s p e c i e s . The v a l i d i t y of the two P a c i f i c s p e c i e s was f i r m l y e s t a b l i s h e d by Lynch (1945), who c o l l e c t e d and examined hundreds of specimens. He c o n c l u d e d t h a t a l t h o u g h t h e r e i s c o n s i d e r a b l e v a r i a t i o n i n the e x t e r n a l f e a t u r e s i n both s p e c i e s , t h e r e i s n o n e t h e l e s s l i t t l e or no o v e r l a p . In a d d i t i o n , the two s p e c i e s can a l s o be d i s t i n g u i s h e d on the b a s i s of i n t e r n a l m o r p h o l o g i c a l f e a t u r e s . G y r o c o t y l i d s p a r a s i t i z e o n l y h o l o c e p h a l a n f i s h e s , and i n f e c t i o n r a t e s as h i g h as 98% have been r e c o r d e d (Simmons and L a u r i e , 1972). I n f e c t i o n s n e a r l y always c o n s i s t of a p a i r of worms s i t u a t e d d i r e c t l y a c r o s s the s p i r a l v a l v e from each o t h e r . M ixed i n f e c t i o n s of two s p e c i e s a r e r a r e (Lynch, 1945; D i e n s k e , 1968; Simmons and L a u r i e , 1972; A l l i s o n and C o a k l e y , 1973). G y r o c o t y l e f i m b r i a t a and G y r o c o t y l e p a r v i s p i n o s a have been found t o occupy d i f f e r e n t s i t e s i n the s p i r a l v a l v e (Simmons and L a u r i e , 1972) and a l s o e x h i b i t d i f f e r e n t p a t t e r n s of c a r b o h y d r a t e a b s o r p t i o n ( L a u r i e , 1974). In c a s e s where two s p e c i e s a r e known from the same h o s t , one s p e c i e s i s more common than the o t h e r (see Van der Land and Templeman, 1968; Simmons, 1974); i n t h e case of Chimaera m o n s t r o s a , one s p e c i e s i s much more common than e i t h e r of the o t h e r two ( D i e n s k e , 1968). 59 A c c o r d i n g t o thes e a u t h o r s , the more common s p e c i e s a r e more c l o s e l y r e l a t e d t o each o t h e r than they a re t o the l e s s common s p e c i e s i n the same h o s t . T h i s a s s e r t i o n may be t e s t e d by p e r f o r m i n g a p h y l o g e n e t i c a n a l y s i s . A f u r t h e r i m p l i c a t i o n of t h i s h y p o t h e s i s i s t h a t an i n i t i a l s p e c i a t i o n event d i v i d e d g y r o c o t y l i d s i n t o two l i n e a g e s which s u b s e q u e n t l y c o e v o l v e d w i t h the h o l o c e p h a l a n h o s t s . T h i s h y p o t h e s i s can a l s o be t e s t e d by comparing the p h y l o g e n e t i c r e l a t i o n s h i p s of g y r o c o t y l i d s and h o l o c e p h a l a n s . The b i o g e o g r a p h i c d i s t r i b u t i o n of g y r o c o t y l i d s appears t o be v e r y a n c i e n t . M arine d i s t r i b u t i o n s a r e i n g e n e r a l l e s s w e l l known than a r e f r e s h w a t e r and t e r r e s t r i a l d i s t r i b u t i o n s . The p h y l o g e n e t i c a n a l y s i s w i l l t h e r e f o r e p r e s e n t an o p p o r t u n i t y t o study a n c i e n t marine d i s t r i b u t i o n s . The g y r o c o t y l i d e a n s , l i k e the a m p h i l i n i d e a n s , have been c o n s i d e r e d r e l i c t s . In the case of the g y r o c o t y l i d s , however, t h e i r h i s t o r y seems t o be c l o s e l y l i n k e d w i t h t h a t of the h o l o c e p h a l a n s . S i n c e the h o l o c e p h a l a n s t h e m s e l v e s appear t o have undergone r e l a t i v e l y l i t t l e d i v e r s i f i c a t i o n , e v i d e n c e of c o e v o l u t i o n of the g y r o c o t y l i d e a n s and h o l o c e p h a l a n s would p r o v i d e support f o r the h y p o t h e s i s t h a t the g y r o c o t y l i d e a n s have undergone l i t t l e d i v e r s i f i c a t i o n . 60 METHODS AND MATERIALS C h a r a c t e r t r a n s f o r m a t i o n s e r i e s i n c l u d e d i n the p h y l o g e n e t i c a n a l y s i s were o b t a i n e d t h r o u g h the e x a m i n a t i o n of the a v a i l a b l e p e r t i n e n t l i t e r a t u r e and a l l o b t a i n a b l e specimens. Specimens of a l l d e s c r i b e d s p e c i e s except G y r o c o t y l e meandrica M e n d i v i l - H e r r e r a , 1946, G y r o c o t y l e a b y s s i c o l a (Van der Land and Templeman, 1968) and G y r o c o t y l e major (Van der Land and Templeman) were o b t a i n e d . Specimens of G y r o c o t y l e c o n f u s a van der Land and D i e n s k e , 1968 were, however, i n poor c o n d i t i o n , and c h a r a c t e r s t a t e s were d e t e r m i n e d p r i m a r i l y from the o r i g i n a l d e s c r i p t i o n . I n f o r m a t i o n on G y r o c o t y l e a b y s s i c o l a and G y r o c o t y l e major was o b t a i n e d e n t i r e l y from the o r i g i n a l d e s c r i p t i o n s . The f o l l o w i n g i n s t i t u t i o n s l o a n e d specimens: U. S. N a t i o n a l Museum H e l m i n t h o l g i c a l C o l l e c t i o n , B e l t s v i l l e , M a r y l a n d (USNM); B r i t i s h Museum ( N a t u r a l H i s t o r y ) , London (BMNH); Meguro P a r a s i t o l o g i c a l Museum, Tokyo (MPM); Museum N a t i o n a l d ' H i s t o i r e N a t u r e l l e , Geneva (MNHN); A u s t r a l i a n Museum, Sydney, A u s t r a l i a (AM); N a t u r h i s t o r i s k a R i k s m u s e e t , Stockholm (NHRM); Museum f u r N a t urkunde, Humboldt U n i v e r s i t a t , B e r l i n , D.D.R (MNHU); H a r o l d W. Manter L a b o r a t o r y , L i n c o l n , Nebraska (HWML); Z o o l o g i c a l Museum of t h e U n i v e r s i t y of Bergen (ZMUB); and Z o o l o g i c a l Museum of t h e U n i v e r s i t y of O s l o (ZMUO). Specimens were examined u s i n g a s t e r e o m i c r o s c o p e or compound m i c r o s c o p e ; d rawings were p r e p a r e d w i t h the a i d of a drawing tube or m i c r o p r o j e c t o r . The d a t a were a n a l y z e d u s i n g 61 b o t h H e n n i g i a n a r g u m e n t a t i o n and the PHYSYS computer package f o r q u a n t i t a t i v e s y s t e m a t i c s d e v e l o p e d by D r s . James S. F a r r i s and Mary F. M i c k e v i c h . T r a n s f o r m a t i o n s e r i e s were i d e n t i f i e d u s i n g the o u t g r o u p method of comparison (see Hennig, 1966; W i l e y , 1981; Brooks e t a l . , 1984) Three o u t g r o u p s , the monogeneans, a m p h i l i n i d e a n s and tapeworms, were used i n o r d e r t o minimze a m b i g u i t i e s r e s u l t i n g from e v o l u t i o n of the o utgroup t a x a (see Maddison e_t §_1. , 1984). For c h a r a c t e r i s t i c s not found i n the study group, an a p p r o p r i a t e f u n c t i o n a l outgroup w i t h i n the s t u d y group was employed, f o l l o w i n g the methods of Watrous and Wheeler (1981). The f i t of i n d i v i d u a l t r a n s f o r m a t i o n s e r i e s was checked u s i n g F a r r i s o p t i m i z a t i o n ( F a r r i s , 1970). P r e s e n t e d i n f o r m a t i o n i n c l u d e s : (1) the c h a r a c t e r a n a l y s i s , i n c l u d i n g a d i s c u s s i o n of the t e r m i n o l o g y employed i n g y r o c o t y l i d s y s t e m a t i c s ; (2) a h y p o t h e s i s of p h y l o g e n e t i c r e l a t i o n s h i p and c l a s s i f i c a t i o n f o r the g y r o c o t y l i d e a n s ; (3) p h y l g e n e t i c d i a g n o s e s of the g y r o c o t y l i d s p e c i e s r e c o g n i z e d , i n c l u d i n g p a r t i a l l i s t s of synonyms, and l i s t s of the h o s t s , l o c a l i t i e s and the specimens examined. (4) a key t o the s p e c i e s of g y r o c o t y l i d s ; (5) a d i s c u s s i o n of h o s t — p a r a s i t e c o e v o l u t i o n f o r t h e g y r o c o t y l i d s and h o l o c e p h a l a n s ; and (6) a d i s c u s s i o n of t h e i r b i o g e o g r a p h y . In t h e c h a r a c t e r a n a l y s i s s e c t i o n , 0 i s a l w a y s used t o r e p r e s e n t t h e p l e s i o m o r p h i c c o n d i t i o n f o r the n u m e r i c a l c o d i n g . A l l of the i n f o r m a t i o n used i n the p h y l o g e n e t i c a n a l y s i s was o b t a i n e d from d i r e c t e x a m i n a t i o n of specimens u n l e s s o t h e r w i s e 62 n o t e d . The t e r m i n o l o g y employed c o r r e s p o n d s , i n g e n e r a l , t o p r e v i o u s usage (see Lynch, 1945). Wherever p o s s i b l e , specimens from more than one c o l l e c t i o n were examined. T h i s p r o v i d e d an e s t i m a t e of both i n t r a s p e c i f i c v a r i a t i o n and of t h e degree of specimen d i s t o r t i o n i n p r e s e r v a t i o n . Where l a r g e numbers of specimens c o u l d not be compared, i t was n e c e s s a r y t o e x t r a p o l a t e from o b s e r v a t i o n s of the v a r i a b i l i t y i n s p e c i e s which a r e b e t t e r r e p r e s e n t e d i n museum c o l l e c t i o n s . CHARACTER ANALYSIS 1. Cercomer hooks. G y r o c o t y l i d s p o s s e s s ten e q u a l - s i z e d cercomer hooks. The number of cercomer hooks d i f f e r s f o r each of the cercomeromorph t a x a , so the p l e s i o m o r p h i c hook number i s d i f f i c u l t t o d e t e r m i n e . However, i t seems l i k e l y t h a t the presence of ten e q u a l s i z e d hooks can s t i l l be c o n s i d e r e d a synapomorphy f o r the g y r o c o t y l i d s . 2. P o s t e r i o r A d h e s i v e Organ. G y r o c o t y l i d s p o s s e s s a c o n i c a l or c y l i n d r i c a l a d h e s i v e organ, c a l l e d a f u n n e l or r o s e t t e , which opens t o the d o r s a l s u r f a c e t h r o u g h a muscular pore (see f i g . 2 3 ) . P o s t l a r v a e a r e found a t t a c h e d t o the end of a v i l l u s by the cercomer hooks, and the f u n n e l appears t o d e v e l o p as a sheet of t i s s u e which grows down over one or more of the i n t e s t i n a l v i l l i ( H a l v o r s e n and W i l l i a m s , 1968). A l t h o u g h the "development of the o p i s t h a p t o r i n p o l y o p i s t o c o t y l e a n monogeneans (see Bychowsky, 1957) i s s i m i l a r t o the development of the f u n n e l i n 63 g y r o c o t y l i d s , the a d h e s i v e organ of the g y r o c o t y l i d s i s un i q u e , and i s c o n s i d e r e d a synapomorphy f o r the group. The f u n n e l may v a r y both i n l e n g t h and i n b a s a l d i a m e t e r . The l e n g t h may be e i t h e r more or l e s s than a t h i r d of the t o t a l body l e n g t h , and the maximum dia m e t e r may be on average l e s s than or g r e a t e r than h a l f of the maximum body d i a m e t e r . Three s t a t e s a r e o b s e r v e d : s h o r t and narrow ( f i g s . 27, 31-34), l o n g and narrow ( f i g . 30) and s h o r t and wide ( f i g s . 35-38). The s h o r t wide f u n n e l and the l o n g narrow f u n n e l appear t o have a r i s e n i n d e p e n d e n t l y from the s h o r t narrow f u n n e l . The t h r e e s t a t e s a r e d e s c r i b e d w i t h two t r a n s f o r m a t i o n s e r i e s , u s i n g a m o d i f i c a t i o n of m u l t i s t a t e c o d i n g : f u n n e l a b s e n t , (0,0) s h o r t narrow f u n n e l ( 1 , 1 ) , s h o r t wide f u n n e l (1,2) and l o n g narrow f u n n e l ( 2 , 1 ) . The p o s t e r o r margin of the f u n n e l i n most s p e c i e s i s p l i c a t e d and has been c a l l e d the r o s e t t e . G y r o c o t y l i d s p e c i e s a r e u s u a l l y d e s c r i b e d as h a v i n g e i t h e r a s i m p l e or a complex r o s e t t e , or as h a v i n g no r o s e t t e ( G y r o c o t y l e n y b e l i n i . ) The degree of f o l d i n g of the p o s t e r i o r margin of the f u n n e l appears t o be a f u n c t i o n of the r e l a t i v e h e i g h t and d i a m e t e r of the f u n n e l , i . e . a l l s h o r t wide f u n n e l s a r e a l s o c o m p l e x l y f o l d e d . I n c l u s i o n of a d e s c r i p t i o n of the f o l d i n g of the f u n n e l margin would be redundant w i t h a d e s c r i p t i o n of the f u n n e l d i m e n s i o n s . The term " r o s e t t e " w i l l t h e r e f o r e be used i n t e r c h a n g e a b l y w i t h " f u n n e l " h e r e . 64 3. P l i c a t e d m a r g i n s . Most g y r o c o t y l i d s p e c i e s have e l a b o r a t e l y p l i c a t e d or c r e n a t e m a r g i n s . A p l i c a t i o n i s c o n s i d e r e d t o be a s i n g l e s e m i c i r c u l a r f o l d of the l a t e r a l m a r g i n . Where p l i c a t i o n s a r e absent the margins a r e c r e n u l a t e , a p p e a r i n g s e r r a t e d or wavy under m a g n i f i c a t i o n ( f i g s . 27, 3 0 ) . Where c r e n a t e margins a r e p r e s e n t , the p l i c a t i o n s may be numerous and complex, w i t h many secondary f o l d s ( f i g s . 35-38), or few and s i m p l e w i t h no secondary f o l d i n g ( f i g s . 31-34). A number of a u t h o r s ( see f o r example, Lonnberg, 1891; Ward, 1912; D o l l f u s , 1922; and Wardle, 1932) have e x p r e s s e d c o n c e r n t h a t the degree of f o l d i n g i s e n t i r e l y dependent on the s t a t e of c o n t r a c t i o n of the specimen. I agree w i t h Lynch (1945), who c o n c l u d e d t h a t a l t h o u g h c o n s i d e r a b l e d i s t o r t i o n of the body can o c c u r , t h e r e i s l i t t l e or no o v e r l a p of the number of p l i c a t i o n s p r e s e n t i n the s p e c i e s d e s c r i b e d as e l a b o r a t e l y p l i c a t e d and t h o s e d e s c r i b e d as m o d e r a t e l y p l i c a t e d . C r e n u l a t e margins a r e ob s e r v e d i n o t h e r c e r c o m e r i a n s o n l y as an a r t i f a c t , and the absence of c r e n a t e or c r e n u l a t e margins i s c o n s i d e r e d p l e s i o m o r p h i c ( 0 ) . The b e s t f i t i s o b t a i n e d when the pr e s e n c e of c r e n u l a t e margins i s coded as ( 1 ) , m o d e r a t e l y p l i c a t e d margins as (2) and e l a b o r a t e l y p l i c a t e d margins as ( 3 ) . 4. G e n i t a l n o t c h . Most g y r o c o t y l i d s have a n o t c h i n the s i d e of t h e body a t the l e v e l of t h e g e n i t a l pores (see f i g . 2 4 ) . The n o t c h may be deep and pronounced, sometimes w i t h a s h a l l o w m a tching n o t c h on the o p p o s i t e s i d e of the body, or s h a l l o w and 65 l e s s pronounced, almost always w i t h o u t a matching n o t c h . In a s i n g l e s p e c i e s , G y r o c o t y l e n y b e l i n i , the g e n i t a l n o t c h i s a b s e n t . The b e s t f i t i s o b t a i n e d f o r t h i s c h a r a c t e r when the p r e s e n c e of t h e g e n i t a l n o t c h i s c o n s i d e r e d p l e s i o m o r p h i c . Where the m a t c h i n g n o t c h o c c u r s , the appearance i s s u g g e s t i v e of monogeneans w i t h b i f u r c a t e l a t e r a l v a g i n a e , but w i t h o n l y one v a g i n a . However, a b e t t e r f i t i s o b t a i n e d when the p r e sence of a s h a l l o w n o t c h i s c o n s i d e r e d r e l a t i v e l y more p l e s i o m o r p h i c , i n d i c a t i n g t h a t the phenomena a r e u n r e l a t e d . The two d e r i v e d s t a t e s , t h e pronounced n o t c h and the absence of the n o t c h a r e c o n s i d e r e d t o have been d e r i v e d i n d e p e n d e n t l y from the p l e s i o m o r p h i c s t a t e . C oding i s as f o l l o w s : s h a l l o w n o t c h , ( 0 , 0 ) ; pronounced n o t c h , ( 0 , 1 ) ; n o t c h a b s e n t , ( 1 , 0 ) . 5. U t e r i n e s a c . The u t e r u s of g y r o c o t y l i d s i s s i n u o u s , o pening d i s t a l l y i n t o a metraterm or u t e r i n e s a c . In two s p e c i e s , G. rugosa and G. c o n f u s a , the sac i s s m a l l , c o n s i s t i n g o n l y of a s l i g h t d i l a t i o n of t h e t e r m i n a l c o i l of the u t e r u s , s i m i l a r t o metraterms found i n o t h e r c e r c o m e r i a n s ; t h i s i s c o n s i d e r e d the p l e s i o m o p h i c s t a t e ( 0 ) . In the r e m a i n i n g s p e c i e s , the sac i s much l a r g e r , i t s l e n g t h r e a c h i n g 1/4 t o 1/2 of the t o t a l e x t e n t of the u t e r u s . In G. n y b e l i n i , t h e sac o c c u p i e s more than o n e — h a l f of the the u t e r i n e e x t e n t . These t h r e e s t a t e s are coded as 0,1, and 2 r e s p e c t i v e l y . 6. Complex c o i l i n g of u t e r u s . The u t e r u s of G. rugosa i s c o m p l e x l y f o l d e d (see f i g s . 27-29), and t h e r e appear t o be 66 s m a l l d i v e r t i c u l i p o s t e r i o r l y . T h i s t r a i t was not ob s e r v e d i n the o t h e r s p e c i e s examined, and the presence of s i m p l e s i n u o u s c o i l s was t h e r e f o r e c o n s i d e r e d p l e s i o m o r p h i c ( 0 ) . The pr e s e n c e of complex c o i l i n g of the u t e r u s i s c o n s i d e r e d apomorphic ( 1 ) . 7. P o s i t i o n of t h e T e s t e s . G y r o c o t y l i d s have f o l l i c u l a r t e s t e s which l i e i n s p i n d l e - s h a p e d bands on e i t h e r s i d e of the body a t the l e v e l of the u t e r i n e sac (see f i g . 25). The t e s t e s may exte n d t o the a n t e r i o r margin of the u t e r i n e s a c , t o the p o s t e r i o r margin of the u t e r i n e sac or beyond the p o s t e r i o r m a r g in. Where the t e s t e s extend t o the p o s t e r i o r margin of the u t e r i n e sac or beyond, the l e n g t h of the t e s t i c u l a r bands c o v a r i e s w i t h the l e n g t h of the u t e r i n e s a c . R e l a t i v e t o the t o t a l l e n g t h of the body o c c u p i e d by the u t e r u s , the t e s t i c u l a r bands may occupy l e s s than o n e - q u a r t e r , a p p r o x i m a t e l y o n e - h a l f , or a p p r o x i m a t e l y t w o - t h i r d s of the l e n g t h . The pr e s e n c e of t e s t i c u l a r bands e x t e n d i n g beyond the p o s t e r i o r end of the u t e r i n e sac i s c o n s i d e r e d p l e s i o m o r p h i c ( 0 ) , as some o t h e r cercomeromorph t a x a have l o n g t e s t i c u l a r bands. The best f i t i s o b t a i n e d when the presence of t e s t i c u l a r bands e x t e n d i n g t o the p o s t e r i o r margin of a medium s i z e d u t e r i n e sac i s c o n s i d e r e d t o be d e r i v e d d i r e c t l y from the p l e s i o m o r p h i c s t a t e , and the l o n g e r and s h o r t e r bands d e r i v e d i n d e p e n d e n t l y from t h i s s t a t e . Two t r a n s f o r m a t i o n s e r i e s have been used t o d e s c r i b e the e x t e n t of the t e s t e s . Coding i s as f o l l o w s : t e s t e s e x t e n d i n g beyond the p o s t e r i o r margin of the u t e r i n e sac ( 0 , 0 ) ; t e s t e s e x t e n d i n g t o the p o s t e r i o r margin of the u t e r i n e sac ( 1 , 1 ) ; t e s t e s e x t e n d i n g 67 t o the p o s t e r i o r margin of an e n l a r g e d u t e r i n e sac ( 1 , 2 ) ; and t e s t e s e x t e n d i n g o n l y as f a r as t h e a n t e r i o r margin of the u t e r i n e sac ( 2 , 1 ) . 8. C o p u l a t o r y p a p i l l a . The tegument s u r r o u n d i n g the male pore may be p r o t r u d e d t o form a c o p u l a t o r y p a p i l l a . T h i s s t r u c t u r e has a t times been c a l l e d a c i r r u s , p e n i s , or p e n i s p a p i l l a . These terms have d i f f e r e n t and s p e c i f i c meanings f o r o t h e r p l a t y h e l m i n t h t a x a . In a d d i t i o n , t h e y have been a p p l i e d t o a v a l v e i n the e j e c u l a t o r y duct a t t h e l e v e l of the e j a c u l a t o r y b u l b . The term c o p u l a t o r y p a p i l l a i s t h e r e f o r e i n t r o d u c e d . Specimens a r e not always f i x e d w i t h t h e p a p i l l a p r o t r u d i n g , and a s p e c i e s t h e r e f o r e cannot be d e s c r i b e d as l a c k i n g a p a p i l l a u n l e s s a l a r g e number of specimens have been examined. The s i n g l e specimen of G_^  n i g r o s e t o s a examined l a c k s a c o p u l a t o r y p a p i l l a , so t h i s c h a r a c t e r i s t i c has been t r e a t e d as though no i n f o r m a t i o n was a v a i l a b l e (coded as 9) In a d d i t i o n , no i n f o r m a t i o n i s a v a i l a b l e on c o n f u s a . p a r v i s p i n o s a , G. f i m b r i a t a , and G^ urna have been s t u d i e d t h o r o u g h l y and appear not t o have a c o p u l a t o r y p a p i l l a . C o p u l a t o r y p a p i l l a e are observed i n o t h e r p l a t y h e l m i n t h t a x a , so the pr e s e n c e of a p a p i l l a seems t o be p l e s i o m o r p h i c and the absence appears t o be a l o s s . T h i s c o d i n g a l s o produces t h e be s t f i t w i t h o t h e r c h a r a c t e r s i n c l u d e d i n the a n a l y s i s . 9. Tegumental s p i n e s . G y r o c o t y l i d s p o s s e s s tegumental s p i n e s which p o i n t towards the a n t e r i o r end of the body. The presence 68 of t h e s e s p i n e s i s c o n s i d e r e d p l e s i o m o r p h i c ( 0 ) , as o t h e r c e r c o m e r i a n s a l s o have t e g u m e n t a l s p i n e s . In a s i n g l e s p e c i e s , G y r o c o t y l e n y b e l i n i , the tegumental s p i n e s a r e a b s e n t ; t h i s i s an autapomorphic t r a i t ( 1 ) . 10. Spine shape. The shape of the tegumental s p i n e s of g y r o c o t y l i d s i s h i g h l y v a r i a b l e , u s u a l l y e x h i b i t i n g v a r i a t i o n on the body of a s i n g l e i n d i v i d u a l , as w e l l as among i n d i v i d u a l s , p o p u l a t i o n s and s p e c i e s (see van der Land and Templeman, 1968; Simmons and L a u r i e , 1972) Two s p i n e shapes are r e a d i l y i d e n t i f i a b l e . Van der Land and D i e n s k e (1968) and Van der Land and Templeman (1968) have d e s i g n a t e d these the urna and c o n f u s a t y p e s . In g e n e r a l , s p i n e s of t h e f i r s t type a r e s h o r t and t h i c k w i t h t h i c k , b l u n t t i p s . S p i n e s of the second type a r e l o n g and s l e n d e r , and have f i n e r , s h a r p e r t i p s . A c c o r d i n g t o van der Land and c o w o r k e r s , s p i n e s of the l a t t e r t y pe a re more s y m m e t r i c a l ; I have o b s e r v e d a g r e a t d e a l of v a r i a t i o n i n symmetry and t h e r e f o r e have not i n c l u d e d symmetry i n the d e s c r i p t i o n s of s p i n e shape. The presence or absence of p r o x i m a l e x t e n s i o n s of the s p i n e s (see f i g . 26) i s s i m i l a r l y i n c o n s i s t e n t and has a l s o been o m i t t e d from the a n a l y s i s . The p r e s ence of l o n g s l e n d e r s p i n e s i s c o n s i d e r e d apomorphic and the presence of s h o r t stubby s p i n e s i s c o n s i d e r e d p l e s i o m o r p h i c . T h i s p o l a r i z a t i o n produces the be s t f i t of t h i s c h a r a c t e r t o the o t h e r c h a r a c t e r s used i n the p h y l o g e n e t i c a n a l y s i s . 69 11. S p i n e d i s t r i b u t i o n . Three p a t t e r n s of s p i n e d i s t r i b u t i o n a r e o b s e r v e d . In G y r o c o t y l e r u g o s a , l a r g e s p i n e s a r e p r e s e n t a t the a n t e r i o r end of the body on e i t h e r s i d e of the a p i c a l i n v a g i n a t i o n . A c c o r d i n g t o Manter (1951), t i n y s p i n e s a r e p r e s e n t on most of t h e body s u r f a c e . Manter o b s e r v e d the s m a l l e r s p i n e s on l i v i n g specimens o n l y ; I was unable t o l o c a t e t h e s e s p i n e s on p r e s e r v e d specimens. A p p r o x i m a t e l y h a l f of the r e m a i n i n g s p e c i e s have l a r g e s p i n e s l i k e the p h a r y n g e a l s p i n e s of G y r o c o t y l e rugosa p r e s e n t a l l over the body i n c l u d i n g on the body m a r g i n s . The o t h e r h a l f of the r e m a i n i n g s p e c i e s have s p i n e s c o n f i n e d almost e n t i r e l y t o the p o s t e r i o r h a l f of the body, and o n l y o c c a s i o n a l l y have s p i n e s on the body m a r g i n s . The outgroup t a x a i n c l u d e s p e c i e s w i t h s m a l l s p i n e s e x t e n d i n g the e n t i r e l e n g t h of the body, so t h i s s t a t e i s c o n s i d e r e d p l e s i o m o r p h i c ( 0 ) . The presence of l a r g e s p i n e s on most of the body s u r f a c e i n c l u d i n g the margins i s c o n s i d e r e d t o be apomorphic, and the r e d u c t i o n i n the number of s p i n e s i s c o n s i d e r e d t o be f u r t h e r d e r i v e d (coded as 1 and 2 r e s p e c t i v e l y ) . CHARACTERS NOT INCLUDED IN THE ANALYSIS The r e l a t i v e p o s i t i o n s of the male, v a g i n a l and u t e r i n e pores v a r y somewhat among s p e c i e s of G y r o c o t y l e . These c h a r a c t e r i s t i c s have not been i n c l u d e d i n the a n a l y s i s as d i s t o r t i o n of the body i n p r e s e r v a t i o n does seem t o a f f e c t the 70 pore p o s i t i o n s (see a l s o Watson, 1911). In a d d i t i o n , s i n c e many of the specimens a v a i l a b l e f o r study a r e i n poor c o n d i t i o n , the pore s are o f t e n s i m p l y not v i s i b l e . Much the same i s t r u e f o r the p o s i t i o n of the e x c r e t o r y p o r e s . The body s i z e has not been i n c l u d e d , as the s i z e appears t o be c o r r e l a t e d w i t h the s i z e of the h o s t s r a t h e r than w i t h the p a r a s i t e p h y l o g e n y . P a r a s i t e s found i n a s i n g l e host s p e c i e s a r e a p p r o x i m a t e l y the same s i z e , a l t h o u g h they may not be c l o s e l y r e l a t e d . RESULTS Twenty-four c h a r a c t e r s t a t e s c o m p r i s i n g t h i r t e e n homologous s e r i e s were a n a l y z e d i n o r d e r t o p r o v i d e an e s t i m a t e of p h y l o g e n e t i c r e l a t i o n s h i p f o r the g y r o c o t y l i d e a n s . Two t r e e s of e q u a l l e n g t h were o b t a i n e d ( f i g . 3 9 ) ; the c o n s i s t e n c y index f o r each t r e e i s 87.5%. The two t r e e s d i f f e r i n the placement of a s i n g l e t a x o n , G y r o c o t y l e n i g r o s e t o s a , because t h e r e i s no i n f o r m a t i o n on the pr e s e n c e or absence of t h e c o p u l a t o r y p a p i l l a i n t h i s s p e c i e s . The second t r e e ( f i g . 39b), would not be f a l s i f e d by the d i s c o v e r y of t h i s s t r u c t u r e i n G y r o c o t y l e  n i g r o s e t o s a , however. A consensus t r e e i d e n t i f y i n g the common p o i n t s of the t h r e e t r e e s i s shown i n F i g u r e 40. Consensus t r e e s c o n t a i n no new i n f o r m a t i o n ; they a r e s i m p l y d e s c r i p t i o n s of t h e c l a d e s common t o a s e t of p h y l o g e n e t i c t r e e s (see Miyamoto, 1985 f o r a 71 d i s c u s s i o n of the p r o p e r t i e s of consensus t r e e s ) . In the c o n s t r u c t i o n of a consensus t r e e , s t a b i l i t y , r a t h e r than parsimony, i s emphasized; c o n s e q u e n t l y consensus t r e e s a r e l o n g e r than the t r e e s from which they a r e c o n s t r u c t e d . Diagnoses p r e s e n t e d here a r e p h y l o g e n e t i c d i a g n o s e s , and t h e r e f o r e are r e s t r i c t e d almost e n t i r e l y t o i n f o r m a t i o n used i n the a n a l y s i s ; the d i a g n o s e s a r e not i n t e n d e d t o s e r v e as d e s c r i p t i o n s of the s p e c i e s . Numbers i n the d i a g n o s e s r e f e r t o the numbers i n F i g u r e 40, the consensus t r e e . The consensus t r e e has a l s o been used f o r the comparison w i t h h o s t and area r e l a t i o n s h i p s . I n f r a s u b c l a s s G y r o c o t y l i d e a Poche, 1926 Cercomeromorphae w i t h e l o n g a t e c y l i n d r i c a l b o d i e s . Cercomer w i t h t e n e q u a l s i z e d hooks, absent i n a d u l t ( 1 ) . Cercomer d e v e l o p i n g i n t o s h o r t narrow p o s t e r i o r f u n n e l attachment organ; f u n n e l opening t o s u r f a c e v i a m u scular d o r s a l pore ( 2 , 3 ) . Body margins c r e n u l a t e ( 4 ) . A n t e r i o r end w i t h muscular pharynx. G e n i t a l n o t c h p r e s e n t j u s t p o s t e r i o r t o pharynx ( 5 ) . V a g i n a l pore near m a r g i n , on d o r s a l s u r f a c e , s l i g h l t y p o s t e r i o r t o g e n i t a l n o t c h . V a g i n a L-shaped, l o o s e l y c o i l e d a n t e r i o r l y , r u n n i n g most of body l e n g t h , opening p o s t e r i o r l y i n t o l a r g e s e m i n a l r e c e p t a c l e . Ovary f o l l i c u l a r , V- or U-shaped, s u r r o u n d i n g t h e s e m i n a l r e c e p t a c l e . U t e r u s s i n u o u s l y c o i l e d , o p e n i n g a n t e r i o r l y i n t o s m a l l metraterm or u t e r i n e s a c . U t e r i n e pore median, v e n t r a l , l o c a t e d a t the a n t e r i o r end of the u t e r i n e 72 s a c . T e s t e s f o l l i c u l a r , i n s p i n d l e - s h a p e d bands e x t e n d i n g from the p o s t e r i o r end of the pharynx t o t h e p o s t e r i o r margin of the u t e r i n e s a c . Vas d e f e r e n s c o i l e d , o p e ning i n t o muscular e j a c u l a t o r y b u l b . Male duct o pening t o v e n t r a l s u r f a c e median t o the v a g i n a l pore and a t the l e v e l of the g e n i t a l n o t c h . S m a l l tegumental s p i n e s p r e s e n t over much of body s u r f a c e ; l a r g e r s p i n e s p r e s e n t on e i t h e r s i d e of pharynx ( 7 ) . L a r g e r s p i n e s l o n g and s l e n d e r ( 6 ) . P a r a s i t e s of h o l o c e p h a l a n f i s h e s ; c o s m o p o l i t a n . Type s p e c i e s : G y r o c o t y l e rugosa D i e s i n g , 1850. Order G y r o c o t y l i f o r m e s Poche, 1926 W ith the c h a r a c t e r s of the i n f r a s u b c l a s s . F a m i l y G y r o c o t y l i d a e Benham, 1901 W i t h the c h a r a c t e r s of the o r d e r ; type genus G y r o c o t y l e D i e s i n g , 1850 Genus G y r o c o t y l e D i e s i n g , 1850 C r o b y l o p h o r u s K r o y e r , 1852 Amphiptyches Wagener, 1852 Amphiptyches: Joyeux and Baer, 1951 ( p a r t i m ) G y r o c o t y l o i d e s Fuhrmann, 1931 ( p a r t i m ) W i t h t h e c h a r a c t e r s of the f a m i l y . G y r o c o t y l e rugosa D i e s i n g , 1850 ( f i g s . 27-29) 73 G y r o c o t y l e rugosa D i e s i n g , 1850 ( o r i g i n a l d e s c r i p t i o n from a South A f r i c a n u n g u l a t e , A n t i l o p e p y g a r g a ) . G y r o c o t y l e  r u g o s a : M o n t i c e l l i , 1889: 321-325, p i . 33 ( r e i d e n t i f i c a t i o n of hos t as C a l l o r h i n c h u s c a l l o r h y n c h u s ) ; H a s w e l l , 1902: 48-54, p i . 7; ( l i s t e d ) ; von L i n s t o w , 1901: 271-291, f i g s . 37-41 ( r e d e s c r i p t i o n from a South A f r i c a n u n g u l a t e ; H u n g e r b u h l e r , 1910: 1-26, p i s . 1,2; Watson, 1911: 431-432 MacDonagh, 1927: 1232-1233: ( s u p p l e m e n t a l m o r p h o l o g i c a l i n f o r m a t i o n ) ; Lynch, 1945: 435-437 ( p r o v i s i o n a l r e d e s c r i p t i o n ) ; M e n d i v i 1 - H e r r e r a , 1946: 1-2 ( s u p p l e m e n t a l m o r p h o l o g i c a l i n f o r m a t i o n ) ; Joyeux and Baer, 1951: 371-378, f i g s . 1-6 ( r e d e s c r i p t i o n ) ; Manter, 1951: 1-11, f i g s . 1-10 ( r e d e s c r i p t i o n ) ; A l l i s o n and C o a k l e y , 1973: .381-394, 3a, 4b, 5, 7. 773 G y r o c o t y l e p l a n a L i n t o n , 1924 ( s u p p l e m e n t a l m o r p h o l o g i c a l i n f o r m a t i o n ) ; G. p l a n a : Yamaguti, 1959: 17 ( l i s t e d ) . Specimens examined: AM #W3649; MNHU #4746; HWML (2 specimens, w i t h o u t numbers); a d d i t i o n a l specimens o b t a i n e d from Dr. F. R. A l l i s o n , U n i v e r s i t y of C a n t e r b u r y , New Zealand. H o s t s : C a l l o r h i n c h u s c a l l o r h y n c h u s L. L o c a l i t i e s : Southern s e a s : South A f r i c a , South A m e r i c a , New Ze a l a n d . Taxonomic c h a r a c t e r i s t i c s : G y r o c o t y l i d e a w i t h e l o n g a t e body, 33.2-65.8mm l o n g , 13.8-19.4 mm wide. F u n n e l s h o r t and narrow, 74 4.2- 12.1 mm wide, or 21-66% of maximum body w i d t h . U t e r u s e l a b o r a t e l y c o i l e d ( 8 ) , w i t h s m a l l u t e r i n e s a c . T e s t e s e x t e n d i n g beyond the p o s t e r i o r margin of the u t e r i n e sac ( 5 ) . Large tegumental s p i n e s c o n f i n e d t o the p h a y r n g e a l r e g i o n ; s m a l l t egumental s p i n e s p r e s e n t on much of body s u r f a c e . P h a r y n g e a l s p i n e s s h o r t and t h i c k ( 9 ) . Remarks: D i e s i n g d e s c r i b e d t h i s s p e c i e s , o r i g i n a l l y l i s t i n g t h e host as A n t i l o p e p y a r g a . M o n t i c e l l i (1889) r e d e s c r i b e d t h i s s p e c i e s , t h i s time w i t h the host l i s t e d as C a l l o r h i n c h u s  c a l l o r h y n c h u s , a h o l o c e p h a l a n f i s h . E a r l y d e s c r i p t i o n s were o f t e n c o n f l i c t i n g , perhaps because some were based on mixed c o l l e c t i o n s (see Lynch, 1945). Lynch (1945) r e v i v e d i n t e r e s t i n the s p e c i e s by c o n s t r u c t i n g a p r o v i s i o n a l d i a g n o s i s . Two r e d e s c r i p t i o n s , Manter (1951) and Joyeux and Baer <1951 ) s u b s e q u e n t l y appeared. G y r o c o t y l e n y b e l i n i (Fuhrmann, 1931) comb, n. ( f i g u r e 30) G y r o c o t y l e u r n a : Lonnberg, 1890: 23, 44 ( p a r t i m ) ; 1891: 9-47, p i . 3 f i g . 36 ( p a r t i m ) ; O l s s o n , 1896: 509, f i g . 9 ( p a r t i m ) . G y r o c o t y l o i d e s n y b e l i n i Fuhrmann, 1931: 161-178, f i g s . 193, 194 ( o r i g i n a l d e s c r i p t i o n , from Chimaera m o n s t r o s a ) . G y r o c o t y l o i d e s n y b e l i n i : Lynch, 1945: 433, 437 ( l i s t e d ) ; 75 Joyeux and Baer, 1950: 71-79, f i g s . 1-9 ( r e d e s c r i p t i o n ) ; 1951: 377, 379, f i g . 6 ( l i s t e d ) ; Wardle and McLeod, 1952: 637 ( l i s t e d ) ; Yamaguti, 1959: 17-18 p i . 22, f i g . 167 ( l i s t e d ) ; Joyeux and Baer, 1961: 250, f i g . 246A ( l i s t e d ) ; D i e n s k e , 1968: 43-44, p i . 1 f i g . C, f i g . 9 ( l i s t e d ) ; van der Land and Templeman, 1968: 1283-1284 ( l i s t e d ) . Specimens examined: MNHN 90/1-98 H o s t s : Chimaera monstrosa L. L o c a l i t i e s : Found i n s m a l l numbers, and o n l y i n the v i c i n i t y of Bergen, Norway. Taxonomic c h a r a c t e r i s t i c s : G y r o c o t y l i d e a w i t h body 6.8-33.4 mm l o n g , 1.2-2.8 mm wide. A n t e r i o r end p o i n t e d ; g e n i t a l n o t c h absent ( 2 1 ) . Pharynx weakly d e v e l o p e d . F u n n e l e l o n g a t e , 2.4 t o 16.6 mm l o n g or 36-50% of t o t a l body l e n g t h ( 1 7 ) . F u n n e l v e r y narrow, 350-2800 um i n d i a m e t e r w i t h l a r g e s u b t e r m i n a l s p h i n c t e r muscle. F u n n e l margin v e r y s i m p l y p l i c a t e d ; body margins c r e n u l a t e ( 2 0 ) . U t e r u s c o n s i s t i n g of a few s i m p l e c o i l s , o p ening i n t o a v e r y l a r g e u t e r i n e sac which sac o c c u p i e s more than 2/3 of t o t a l u t e r i n e e x t e n t ( 2 2 ) . W a l l s of u t e r i n e sac p l e a t e d . T e s t e s d e n s e l y packed, e x t e n d i n g from the base of the pharynx t o the base of t h e u t e r i n e sac ( 1 8 ) . T e s t i c u l a r f i e l d s j o i n e d a n t e r i o r t o the u t e r u s . Tegumental s p i n e s absent ( 1 9 ) . Remarks: Lonnberg (1890, 1891) was the f i r s t t o o b s e r v e t h i s s p e c i e s . He thought i t t o be G y r o c o t y l e urna i n an u n u s u a l 76 s t a t e of c o n t r a c t i o n , a l t h o u g h he r e p o r t e d t h a t some of h i s c o l l e a g u e s d i s a g r e e d . Fuhrmann (1931) d e s c r i b e d t h i s s p e c i e s from a c o l l e c t i o n of p a r a s i t e s of Chimaera m o n s t r o s a . The i l l u s t r a t i o n s p r o v i d e d i n Fuhrmann's d e s c r i p t i o n a r e of an immature specimen, which l e d Lynch (1945) t o s p e c u l a t e t h a t t h i s might r e p r e s e n t an immature specimen of G y r o c o t y l e urna i n an u n u s u a l s t a t e of c o n t r a c t i o n . Joyeux and Baer (1950) p r o v i d e d a c o n v i n c i n g r e d e s c r i p t i o n . G y r o c o t y l e p a r v i s p i n o s a Lynch, 1945 ( f i g u r e 32) G y r o c o t y l e urna ( v a r . ?) Watson, 1911: 365," 370-371, p i . 34 f i g . 13, p i . 36 f i g . 21, p i . 48 f i g . 83; ( o r i g i n a l d e s c r i p t i o n from H y d r o l a g u s c o l l i e i ) G y r o c o t y l e urna D o l l f u s , 1922: 232-236, ( p a r t i m ; l i s t e d ) ; L y n c h , 1945: 421-426, p i . 2 f i g . 2, p i . 3 f i g . 4, p i . 5 f i g s . 9-18, p i . 6 f i g . 35, p i . 8 f i g . 39, ( p a r t i m ; r e d e s c r i p t i o n ) ; Joyeux and Baer, 1951: 373, 377-378, ( p a r t i m ; l i s t e d ) ; Joyeux and- Baer, 1950: 79 ( p a r t i m ; l i s t e d ) ; Manter, 1951: 2-7 ( p a r t i m ; l i s t e d ) ; Wardle and McLeod, 1952: 659-662, f i g . 417B ( p a r t i m ; l i s t e d ) ; Manter, 1953: 49-51 ( p a r t i m ; l i s t e d ) . G y r o c o t y l e p a r v i s p i n o s a van der Land and D i e n s k e , 1968: 101-103, f i g s . 1-4, p i . 1B (new s t a t u s ) ; G y r o c o t y l e 77 p a r v i s p i n o s a : Simmons and L a u r i e , 1972: 59-77 ( l i s t e d ) ; g. 417B ( p a r t i m ; l i s t e d ) ; Manter, 1953: 49-51 ( p a r t i m ; l i s t e d ) ; Simmons, 1974: 196 ( l i s t e d ) . Specimens examined: USNM #70848-70849; a d d i t i o n a l specimens from the c o l l e c t i o n s of the U n i v e r s i t y of B r i t i s h Columbia. Host: H y d r o l a g u s c o l l i e i Lay and Bennett L o c a l i t i e s : Western c o a s t of N o r t h A m e r i c a , A l a s k a t o Southern C a l i f o r n i a . Taxonomic c h a r a c t e r i s t i c s : G y r o c o t y l i d e a w i t h body 12.9-59.5 mm l o n g , 6.5-11.4 mm wide. F u n n e l 3.6-5.4 mm i n d i a m e t e r , 46-62% of maximum body w i d t h , w i t h s i m p l e p l i c a t e d m a r g i n s . L a t e r a l margins m o d e r a t e l y p l i c a t e d , u s u a l l y w i t h l e s s than 15 p l i c a t i o n s per s i d e ( 1 0 ) . G e n i t a l n o t c h not pronounced ( 6 ) . U t e r i n e sac l a r g e ( 1 2 ) ; t e s t e s e x t e n d i n g t o a n t e r i o r margin of u t e r i n e sac ( 1 5 ) . C o p u l a t o r y p a p i l l a absent ( 1 6 ) . Large tegumental s p i n e s c o v e r i n g much of body s u r f a c e ( 1 1 ) ; s p i n e s s l e n d e r , f i n e - t i p p e d ( 7 ) . Remarks: T h i s s p e c i e s was f i r s t r e c o g n i z e d by Watson (1911) who gave a b r i e f d e s c r i p t i o n under the name G y r o c o t y l e urna ( v a r . ? ) . S e v e r a l a u t h o r s have c o n s i d e r e d i t a synonym of G y r o c o t y l e u r n a , G y r o c o t y l e f i m b r i a t a or b o t h . Lynch (1945) noted t h a t t h i s s p e c i e s does not conform t o d e s c r i p t i o n s of the European s p e c i e s . He f e l t t h a t Watson's d e s c r i p t i o n was more 78 c o m p l e t e , and t h a t t h e name s h o u l d t h e r e f o r e be r e s t r i c t e d t o s p e c i e s f i t t i n g Watson's d e s c r i p t i o n . Van der Land and D i e n s k e (1968) have argued t h a t t y p e c o l l e c t i o n s of G y r o c o t y l e urna s t i l l remain i n B e r l i n , and can s t i l l be used t o i d e n t i f y t he European s p e c i e s . These a u t h o r s have a c c o r d i n g l y renamed G y r o c o t y l e urna sensu Watson, 1911 G y r o c o t y l e p a r v i s p i n o s a , u s i n g the name of one of the two forms r e c o g n i z e d by Lynch (1945). As Simmons (1974) has n o t e d , t h i s i s an u n f o r t u n a t e c h o i c e of names, as t h e two forms r e c o g n i z e d by Lynch a r e r e a d i l y i d e n t i f i a b l e . I t appears t o me t h a t the two forms r e p r e s e n t extreme ends of a continuum, as some specimens a r e d i f f i c u l t t o i d e n t i f y p o s i t i v e l y as one form or the o t h e r . I t i s i n t e r e s t i n g t o note t h a t c o l l e c t i o n s of t h i s s p e c i e s made by D. R. Brooks i n B a m f i e l d , B r i t i s h C o l u m b i a , c o n s i s t a lmost e n t i r e l y of the forma m a g n i s p i n o s a , whereas c o l l e c t i o n s from F r i d a y H a r b o r , Washington ( e . g . Lynch, 1945; Simmons and L a u r i e , 1972) appear t o c o n s i s t p r i m a r i l y of the forma p a r v i s p i n o s a . I t t h e r e f o r e seems p o s s i b l e t h a t t h e s e forms may s i m p l y r e p r e s e n t g e o g r a p h i c v a r i a n t s . G y r o c o t y l e maxima (MacDonagh, 1927) ( f i g u r e 31) G y r o c o t y l e maxima MacDonagh, 1927: 1234-1235, f i g s . 5-9 ( o r i g i n a l d e s c r i p t i o n from M u s t e l u s a s t e r i a s ) . G y r o c o t y l e  maxima: Yamaguti, 1959: 17 ( l i s t e d ) ; Joyeux and Baer, 1951: van der Land and Templeman (1968): 2383 ( l i s t e d ) ; A l l i s o n 79 and C o a k l e y , 1973: 383- 394, f i g s . 3b, 4, 6. ( s u p p l e m e n t a l m o r p h o l o g i c a l i n f o r m a t i o n ) . Amphiptyches urna Spencer, 1889: 138-151, f i g s . 1-13 ( s u p p l e m e n t a l m o r p h o l o g i c a l i n f o r m a t i o n ) . G y r o c o t y l e urna H u n g e r b u h l e r , 1910: 495-522 ( p a r t i m ; l i s t e d ) Manter, 1951 ( p a r t i m ; l i s t e d ) . G y r o c o t y l e meandrica M e n d i v i l - H e r r e r a , 1946 ( o r i g i n a l d e s c r i p t i o n from C a l l o r h i n c h u s c a l l o r h y n c h u s , Uruguay). G y r o c o t y l e m e a n d r i c a : van der Land and Templeman, 1968: 2384 ( l i s t e d ) ; A l l i s o n and C o a k l e y , 1973: 383 ( l i s t e d ) . Specimens examined: MNHU #3462, 4747; an a d d i t i t i o n a l specimen o b t a i n e d from Dr. F. R. A l l i s o n , U n i v e r s i t y of C a n t e r b u r y , New Z e a l a n d . H o s t s : C a l l o r h i n c h u s c a l l o r h y n c h u s L. L o c a l i t i e s : S o u t h e r n s e a s : South A m e r i c a , New Z e a l a n d , South A f r i c a Taxonomic c h a r a c t e r i s t i c s : G y r o c o t y l i d e a w i t h body 32.9 mm l o n g and 7.9 mm wide. F u n n e l narrow, 1.8 mm i n d i a m e t e r or 23% of body w i d t h . F u n n e l margin s i m p l y f o l d e d . M a r g i n s c r e n a t e ( 1 0 ) . G e n i t a l n o t c h pronounced ( 2 3 ) . U t e r i n e sac l a r g e ( 1 2 ) . T e s t e s e x t e n d i n g t o the p o s t e r i o r margin of the u t e r i n e sac (13,14). C o p u l a t o r y p a p i l l a p r e s e n t . S h o r t t h i c k s p i n e s p r e s e n t (24) on 80 most of body s u r f a c e i n c l u d i n g the l a t e r a l margins ( 1 1 ) . Remarks: T h i s s p e c i e s was o r i g i n a l l y d e s c r i b e d by MacDonagh (1927) from a s h a r k ; the o r i g i n a l d e s c r i p t i o n i s p o o r , c o n s i s t i n g p r i m a r i l y of the e x t e r n a l c h a r a c t e r i s t i c s . Type specimens c o u l d not be l o c a t e d . The d e s c r i p t i o n of G.  meandrica M e n d i v i l - H e r r e r a , 1946 has not been used i n p r e p a r i n g t h i s d e s c r i p t i o n , a l t h o u g h some a u t h o r s (Van der Land and Templeman, 1968; A l l i s o n and C o a k l e y , 1973) have c o n s i d e r e d t h i s s p e c i e s t o be a synonym of G_^  maxima MacDonagh, 1927. The d e s c r i p t i o n of G y r o c o t y l e meandr i c a i s a l s o p o o r , and the type specimens a g a i n c o u l d not be l o c a t e d . The s i n g l e s t a i n e d and mounted specimen examined i s from a c o l l e c t i o n i d e n t i f i e d by A l l i s o n and C o a k l e y (1973) as G. maxima• T h i s specimen resembles maxima more c l o s e l y than i t does G^ meandr i c a , e s p e c i a l l y i n the g e n e r a l appearance of the body and i n the c o n f o r m a t i o n of the u t e r u s . The major d i f f e r e n c e between MacDonagh's d e s c r i p t i o n and the specimen examined i s the absence of s p i n e s i n MacDonagh's specimen, a c h a r a c t e r i s t i c which MacDonagh h i m s e l f c o n s i d e r e d t o be an a r t i f a c t . but not d i r e c t l y on the m a r g i n s . G y r o c o t y l e f i m b r i a t a (Watson, 1911) ( f i g u r e 38) G y r o c o t y l e f i m b r i a t a Watson, 1911: 365-370, f i g s . 10, 12, 14-15, 17, 22, 23, 25-35, 37-77 ( o r i g i n a l d e s c r i p t i o n from 81 H y d r o l a g u s c o l l i e i as Chimaera c o l l i e i , C a l i f o r n i a ) . G y r o c o t y l e f i m b r i a t a : Fuhrmann, 1931: 172, f i g . 204 ( l i s t e d ) ; Lynch, 1945: 421-? Simmons and L a u r i e , 1972: 59-77 ( l i s t e d ) . Amphiptyches urna: Joyeux and Baer, 1951: 371, 374, 377-379 ( p a r t im; s u p p l e m e n t a l m o r p h o l o g i c a l i n f o r m a t i o n ) . Specimens examined: MNHU #6872; MPM #18030; USNM #70828, 70832, 70835, 70840; a d d i t i o n a l specimens from the c o l l e c t i o n s of the U n i v e r s i t y of B r i t i s h Columbia. H o s t s : H y d r o l a g u s c o l l i e i Lay and B e n n e t t , Chimaera phantasma J o r d a n and Snyder L o c a l i t i e s : P a c i f i c c o a s t of N o r t h A m e r i c a , from s o u t h e r n C a l i f o r n i a t o A l a s k a ; Japan. Taxonomic c h a r a c t e r i s t i c s : G y r o c o t y l i d e a w i t h body 6.9-52.0 mm l o n g , 6.1-11.0 mm wide. A n t e r i o r end c o n i c a l w i t h pronounced g e n i t a l n o t c h ( 2 3 ) . F u n n e l s h o r t and wide, 3.2-12.1 mm wide or 60-127% maximum body w i d t h ; c o m p l e x l y f o l d e d ( 2 4 ) . L a t e r a l margins c o m p l e x l y f o l d e d ( 2 6 ) . U t e r u s s i m p l y f o l d e d , opening i n t o l a r g e s a c , o c c u p y i n g up t o 1/3 of the t o t a l u t e r i n e e x t e n t ( 1 2 ) . T e s t e s e x t e n d i n g t o t h e p o s t e r i o r margin of the u t e r i n e sac ( 1 3 , 1 4 ) . C o p u l a t o r y p a p i l l a absent ( 2 9 ) . Tegumental s p i n e s l a r g e ( 1 1 ) ; s h o r t arid t h i c k ( 2 4 ) . S p i n e s u s u a l l y absent from the l a t e r a l m a r g i n s ( 2 7 ) . S p i n e s u s u a l l y s p a r s e . 82 G y r o c o t y l e urna (Wagener, 1852) Wagener, 1858 ( f i g u r e 36) C r o b y l o p h o r u s k r o y e r i K r o y e r , 1852: 812-813; 1853:1226-1227 ( o r i g i n a l d e s c r i p t i o n , from a l a m e l l i b r a n c h m o l l u s c , Denmark). Amphityches urna Wagener, 1852: 543-554, f i g s . 1-7 ( o r i g i n a l d e s c r i p t i o n from Chimaera m o n s t r o s a , N i c e ) . D i e s i n g , 1858: 359 ( l i s t e d ) ; M o n t i c e l l i , 1889: 142-144 ( l i s t e d ) ; S c o t t , 1911: 70-71, p i . 8, 1-4 ( l i s t e d ) . Amphiptyches urna Lonnberg, 1890: 23, 24 ( l i s t e d ) ; 1891: 41-47, p i . 3, f i g . 34 ( p a r t i m ; s u p p l e m e n t a l m o r p h o l o g i c a l i n f o r m a t i o n ) ; Joyeux and Baer, 1951: 371, 374, 377-379 ( p a r t i m ; l i s t e d ) . G y r o c o t y l e urna M o n t i c e l l i , 1889: 321-325 ( l i s t e d ) ; L onnberg, 1890a: 55-61 ( l i s t e d ) ; Watson, 1911: 357-363, 371-372, 374,376-382, 384-385, 388, 391, 393, 398, 401,403-404, 407, 411; 415 ( l i s t e d ) ; J o h n s t o n e , 1912: 116-117 ( l i s t e d ) ; R u s z k o w s k i , 1932: 629-641; 1934: 482-485, f i g . 1 ( l i s t e d ) . G y r o c o t y l e urna O l s s o n , 1896; 508-509 ( p a r t i m ; l i s t e d ) ; D o l l f u s , 1922: 206, 217-227, 235-238 (supplementary m o r p h o l o g i c a l i n f o r m a t i o n ) ; Fuhrmann, 1931: 165-168, f i g . 83 176, 193-195, 198-199, 209; Wardle and McLeod, 1952; 659, 661-663; Yamaguti, 1959: 17, p i . 14 f i g . 106 ( p a r t i m ; l i s t e d ) G y r o c o t y l e amphiptyches Wagener i n D i e s i n g , 1858: 359; D i e s i n g , 1859: 447-448 ( l i s t e d ) . G y r o c o t y l e f i m b r i a t a P o l j a n s k i i , 1955: 75, 109, 156, t a b . 22 ( l i s t e d ) . G y r o c o t y l e f i m b r i a t a Lynch, 1945: 432, 436-437 ( p a r t i m ; l i s t e d ) Amphiptyches f i m b r i a t a Joyeux and Baer, 1951: 373, 377-379 ( p a r t i m ; l i s t e d ) . Specimens examined: MNHU #3174, 3215; ZMUO #C324-C332; ZMUB #3454; NHRM #331, 337. Ho s t s : Chimaera monstrosa L. L o c a l i t i e s : N o r t h Sea, e a s t e r n A t l a n t i c Taxonomic c h a r a c t e r i s t i c : G y r o c o t y l i d e a w i t h body 18-49 mm l o n g , 5.9-8.3 wide. A n t e r i o r end c o n i c a l w i t h pronounced g e n i t a l n o t c h ( 2 3 ) . F u n n e l 4.2 t o 5.4 mm wide, c o m p l e x l y f o l d e d ( 2 5 ) . Body margins c o m p l e x l y f o l d e d ( 2 6 ) . U t e r i n e sac l a r g e , o c c u p y i n g 1/4 or more of the t o t a l u t e r i n e e x t e n t ( 1 2 ) . T e s t e s e x t e n d i n g t o the p o s t e r i o r margin of the u t e r i n e sac (13,14). 84 C o p u l a t o r y p a p i l l a absent ( 2 8 ) . Tegumental s p i n e s l a r g e ( 1 1 ) , s h o r t and t h i c k (24)nt ( 1 1 ) . S p i n e s u s u a l l y absent from l a t e r a l m a rgins ( 2 4 ) . S p i n e s r e s t r i c t e d p r i m a r i l y t o p o s t e r i o r h a l f of body. Remarks: The name G y r o c o t y l e urna has been a p p l i e d t o a l l o t h e r g y r o c o t y l i d s p e c i e s mentioned h e r e , except G_^  major and G.  a b y s s i c o l a , a t some p o i n t i n t i m e . The l i s t of synonyms p r o v i d e d here i s by no means e x h a u s t i v e , e s p e c i a l l y f o r v e r y e a r l y c i t a t i o n s . For a more complete l i s t of synonyms f o r t h i s s p e c i e s , see Dienke (1968). Van der Land and Dienske have c o n s i d e r e d Wagener's d e s c r i p t i o n and s e r i e s adequate f o r i d e n t i f i c a t i o n . Specimens d e s i g n a t e d as l e c t o t y p e s by van der Land a r e i n v e r y poor c o n d i t i o n , and a t l e a s t one resembles the d e s c r i p t i o n of G y r o c o t y l e c o n f u s a more than i t does G y r o c o t y l e  u r n a . A p a r t i a l r e d e s c r i p t i o n of t h i s s p e c i e s i s p r e s e n t e d h e r e . A f u l l r e d e s c r i p t i o n i s needed, but cannot be done a d e q u a t e l y from the specimens a v a i l a b l e f o r s t u d y . G y r o c o t y l e c o n f u s a (van der Land and D i e n s k e , 1968) ( f i g u r e 33) Amphiptyches u r n a : Lonnberg, 1891: 9-47, p i . 3 f i g . 35 ( p a r t i m ; m o r p h o l o g i c a l i n f o r m a t i o n ) . G y r o c o t y l e c o n f u s a van der Land and D i e n s k e , 1968: 97-101, 103-105, f i g s . 1-4, p i . 1 f i g . B. G y r o c o t y l e c o n f u s a : 85 D i e n s k e , 1968: 50-51, p i . 1D. Specimens examined: none a v a i l a b l e . H o s t : Chimaera monstrosa L. L o c a l i t y : v i c i n i t y of Bergen, O s l o f j o r d , T r o n d h e i m s f j o r d , B a r e n t s Sea, K a t t e g a t . Taxonomic c h a r a c t e r i s t i c s : G r o c o t y l i d e a 17-28 mm l o n g , 9-14 mm wide. F u n n e l s h o r t and narrow, 27-50% body w i d t h ; f u n n e l margin w i t h s i m p l e f o l d i n g . Body margins c r e n a t e ( 1 0 ) . G e n i t a l n o t c h not pronounced. U t e r i n e sac s m a l l . C o p u l a t o r y p a p i l l a a b s e n t . T e s t e s e x t e n d i n g beyond the p o s t e r i o r margin of t h e u t e r i n e sac. Large s p i n e s p r e s e n t on most of body s u r f a c e ( 1 1 ) ; s p i n e s l o n g and s l e n d e r ( 7 ) . Remarks: Van der Land and D i e n s k e (1968) d e s c r i b e d t h i s s p e c i e s from a number of European c o l l e c t i o n s and r e p o r t s of g y r o c o t y l i d s from Chimaera monstrosa. D i e n s k e (1968) r e p o r t s t h a t l e s s than 20 specimens a r e known. I have examined s e v e r a l fragments of g y r o c o t y l i d s from C. monstrosa w h i c h seem t o f i t the d e s c r i p t i o n of G y r o c o t y l e c o n f u s a more c l o s e l y t h a n they f i t the d e s c r i p t i o n of G y r o c o t y l e u r n a , but the m a t e r i a l i s i n a d e q u a t e f o r a p o s i t i v e i d e n t i f i c a t i o n . A c o m p l e t e l i s t i n g of synonyms has not been p r o v i d e d f o r t h i s s p e c i e s . Many of the e a r l y r e f e r e n c e s are vague, and so I have i n c l u d e d o n l y those w i t h c l e a r and unambiguous i l l u s t r a t i o n s . A c o m p l e t e l i s t i n g of l i k e l y synonyms may be found i n D i e n s k e (1968) and van der Land 86 and D i e n s k e (1968). Two i l l u s t r a t i o n s of G y r o c o t y l e c o n f u s a accompany the o r i g i n a l d e s c r i p t i o n . The two i l l u s t r a t i o n s c l o s e l y resemble i n o u t l i n e the two forms of G y r o c o t y l e  p a r v i s p i n o s a d e s c r i b e d by Lynch (1945). No i n f o r m a t i o n on the two body shapes i s p r o v i d e d i n the t e x t . G y r o c o t y l e a b y s s i c o l a (van der Land and Templeman, 1968) ( f i g u r e 34) G y r o c o t y l e a b y s s i c o l a van der Land and Templeman, 1968: 2365-2384; G y r o c o t y l e a b y s s i c o l a : Hogans and H u r l b u t , 1984: 365 Specimens examined: none a v a i l a b l e . H o s t : H y d r o l a g u s a f f i n i s B r i t o C a p e l l o L o c a l i t y : A t l a n t i c c o a s t of Canada. Taxonomic c h a r a c t e r i s t i c s : G y r o c o t y l i d e a 103 t o 138 mm l o n g and up t o 19 mm wide. G e n i t a l n o t c h pronounced ( 4 ) . F u n n e l s h o r t and narrow, w i t h a maximum w i d t h of 30-45% of the maximum body w i d t h . Body margins c r e n a t e ( 5 ) . U t e r i n e sac l a r g e ( 1 2 ) , a l t h o u g h u t e r u s r e l a t i v e l y s m a l l . T e s t e s e x t e n d i n g t o the p o s t e r i o r margin of the u t e r i n e sac (1 3 , 1 4 ) . C o p u l a t o r y p a p i l l a p r e s e n t . L a r g e tegumental s p i n e s p r e s e n t ( 1 1 ) . S p i n e s l o n g and s l e n d e r ( 7 ) . M a r g i n a l s p i n e s p r e s e n t . 87 G y r o c o t y l e n i g r o s e t o s a ( f i g u r e 35) G y r o c o t y l e n i g r o s e t o s a H a s w e l l , 1902: 48-54 ( f i g s . 1-7; o r i g i n a l d e s c r i p t i o n from H y d r o l a g u s o g i l b y i ) ; G y r o c o t y l e  n i g r o s e t o s a : Watson, 1911: 382 ( f i g . 80; supplementary m o r p h o l o g i c a l i n f o r m a t i o n ) ; van der Land and Templeman, 1968: 2381 ( l i s t e d ) . G y r o c o t y l e urna : J o h n s t o n , 1934: 69-70 ( s u p p l e m e n t a l m o r p h o l o g i c a l i n f o r m a t i o n ) ; Yamaguti, 1934: 3 ( f i g . 1 ; s u p p l e m e n t a l m o r p h o l o g i c a l i n f o r m a t i o n ) ; Lynch, 1945: 437 ( l i s t e d ) . Specimen examined: h o l o t y p e , AM H o s t : H y d r o l a g u s o g i l b y i Waite (as Chimaera o g i l b y i ) . L o c a l i t y : Manly, New South Wales Taxonomic c h a r a c t e r i s t i c s : G y r o c o t y l i d e a w i t h body 54.3 mm l o n g , 9.5 mm wide. A n t e r i o r end c o n i c a l w i t h pronounced g e n i t a l n o t c h ( 2 3 ) . F u n n e l s h o r t and wide, 8.5 mm wide or 89% of maximum body w i d t h ; c o m p l e x l y f o l d e d ( 2 6 ) . U t e r u s s i m p l y f o l d e d , opening i n t o l a r g e sac o c c u p y i n g about o n e - t h i r d of the t o t a l u t e r i n e e x t e n t ( 1 2 ) . T e s t e s e x t e n d i n g t o p o s t e r i o r margin of u t e r i n e sac (13, 14). C o p u l a t o r y p a p i l l a absent ( ? ) . Tegumental s p i n e s l a r g e ( 1 1 ) ; s h o r t and t h i c k ( 2 4 ) . S p i n e s absent from the l a t e r a l m a r gins ( 2 7 ) ; s p i n e s dense. 88 Remarks: The s i n g l e specimen a v a i l a b l e f o r study i s i n poor c o n d i t i o n . T h i s s p e c i e s does resemble G. urna i n many r e s p e c t s . G y r o c o t y l e major (van der Land and Templeman, 1968) ( f i g u r e 3 7 ) . G y r o c o t y l e major van der Land and Templeman, 1968: 2365-2384 ( o r i g i n a l d e s c r i p t i o n ) ; G y r o c o t y l e major: Hogans and H u r l b u t , 1984: 365 ( l i s t e d ) . Specimens examined: none a v a i l a b l e . H o s t s : H y d r o l a g u s a f f i n i s B r i t o C a p e l l o L o c a l i t y : A t l a n t i c c o a s t of Canada. Taxonomic c h a r a c t e r i s t i c s : G y r o c o t y l i d e a 46 -200 mm l o n g and 9-23 mm wide. F u n n e l s h o r t and wide, seldom l e s s than 50% of the maximum body w i d t h ( 2 5 ) . G e n i t a l n o t c h pronounced ( 2 3 ) . Body margins e l a b o r a t e l y c r e n a t e ( 2 6 ) . U t e r i n e sac l a r g e ( 1 2 ) , a l t h o u g h u t e r u s r e l a t i v e l y s m a l l . T e s t e s e x t e n d i n g t o the p o s t e r i o r margin of the u t e r i n e sac (13,14). C o p u l a t o r y p a p i l l a p r e s e n t . Large t e g u m e n t a l s p i n e s p r e s e n t (11 ), a l t h o u g h r e s t r i c t e d almost e n t i r e l y t o the p o s t e r i o r end. S p i n e s s h o r t and t h i c k ( 2 4 ) . M a r g i n a l s p i n e s u s u a l l y absent ( 2 7 ) . 89 KEY TO THE SPECIES OF THE INFRASUBCLASS GYROCOTYLIDEA l a . F u n n e l l e s s than o n e - t h i r d as wide as body 2 1b. Fun n e l a t l e a s t o n e - t h i r d as wide as body 5 2a. F u n n e l a t l e a s t o n e - q u a r t e r as l o n g as body G y r o c o t y l e n y b e l i n i 2b. Fu n n e l l e s s than o n e - q u a r t e r body l e n g t h 3 3a. U t e r i n e sac l e s s than o n e - t h i r d of u t e r i n e l e n g t h 4 3b. U t e r i n e sac a t l e a s t o n e - t h i r d of u t e r i n e l e n g t h 5 4a. Large t e g u m e n t a l s p i n e s p r e s e n t on most of body s u r f a c e G. c o n f u s a 4b. Large t e g u m e n t a l s p i n e s p r e s e n t o n l y around pharynx G. rugosa 5a. Body s p i n e s g e n e r a l l y l o n g and s l e n d e r , t a p e r i n g d i s t a l l y ( c o n f u s a shape) G. p a r v i s p i n o s a 5b. Body s p i n e s g e n e r a l l y s h o r t and t h i c k , t a p e r i n g o n l y s l i g h t l y , (urna shape) G. maxima 6a. S p i n e s v e r y numerous, c o n t i n u o u s from r o s e t t e t o p h a r y n g e a l r e g i o n G. n i g r o s e t o s a 6b. S p i n e s r e l a t i v e l y s p a r s e , c o n f i n e d p r i m a r i l y t o p o s t e r i o r h a l f of body 7 7a. C o p u l a t o r y p a p i l l a p r e s e n t G. major 7b. C o p u l a t o r y p a p i l l a absent 8 8a. S p i n e s u s u a l l y v e r y s p a r s e G. f i m b r i a t a 8b. S p i n e s r e l a t i v e l y dense, a l t h o u g h r e s t r i c t e d p r i m a r i l y t o p o s t e r i o r end G. urna 90 DISCUSSION The p h y l o g e n e t i c r e l a t i o n s h i p s of the g y r o c o t y l i d s a r e l e s s r e s o l v e d than a r e t h o s e of the a m p h i l i n i d s , and the r e s o l u t i o n o b t a i n e d i s based on the a n a l y s i s of f a r fewer c h a r a c t e r s and somewhat more tenuous c h a r a c t e r p o l a r i z a t i o n s . G r e a t e r r e l i a n c e has been p l a c e d on f u n c t i o n a l o u t g r o u p s , and g r e a t e r emphasis has been p l a c e d on m a x i m i z i n g the f i t of one c h a r a c t e r t o the o t h e r s used i n the a n a l y s i s because of a l a c k of i n f o r m a t i o n on the o u t g r o u p s t a t e s . Some of the s p e c i e s i n c l u d e d i n my p h y l o g e n e t i c a n a l y s i s have few c h a r a c t e r i s t i c s which can be used t o d i f f e r e n t i a t e them from c l o s e l y r e l a t e d s p e c i e s . The absence of autapomorphies s u g g e s t s t h a t some of the s p e c i e s r e c o g n i z e d here may u l t i m a t e l y be synonomized, e s p e c i a l l y i n the case of the s i n g l e l a r g e polytomy a t the upper end of the t r e e . I t i s a l s o p o s s i b l e t h a t some of the homologous s e r i e s i n c l u d e d i n the a n a l y s i s may be found t o be u n r e l i a b l e or u n i n f o r m a t i v e when more specimens are examined. However, new homologous s e r i e s w i l l u n d o u b t e d l y a l s o be d i s c o v e r e d , and i t i s l i k e l y t h a t the a d d i t i o n of new c h a r a c t e r s w i l l i n c r e a s e the r e s o l u t i o n . The weaknesses of t h i s h y p o t h e s i s of p h y l o g e n e t i c r e l a t i o n s h i p stem from the p a u c i t y of adequate specimens a v a i l a b l e f o r s t u d y . A b e t t e r - s u p p o r t e d h y p o t h e s i s must a w a i t the c o l l e c t i o n of new specimens; the h y p o t h e s i s p r e s e n t e d here can s e r v e t o d i r e c t f u t u r e e f f o r t s . In p a r t i c u l a r , the c o l l e c t i o n of l a r g e numbers of specimens w i l l be n e c e s s a r y , as 91 most of the p o t e n t i a l new c h a r a c t e r i s t i c s a r e q u a n t i t a t i v e . In a d d i t i o n , the importance of c o n s i s t e n c y i n the methods of p r e s e r v a t i o n cannot be overemphasized. S p e c i e s such as G y r o c o t y l e u r n a , G y r o c o t y l e f i m b r i a t a and G y r o c o t y l e  n i g r o s e t o s a , w i t h t h e i r e l a b o r a t e l y p l i c a t e d b o r d e r s and wide r o s e t t e s have o f t e n been f i x e d w i t h o u t f l a t t e n i n g , f o r example. I t i s no a c c i d e n t t h a t the r e s o l u t i o n i s p o o r e s t f o r t h e s e spec i e s . No p r e v i o u s p u b l i c a t i o n s on the g y r o c o t y l i d s have i n c l u d e d a b r a n c h i n g diagram. P r e v i o u s c l a s s i f i c a t i o n s of the group i n c l u d e Joyeux and Baer (1951, 1961) and van der Land and Templeman (1968). Joyeux and Baer (1951, 1961) r e c o g n i z e t h r e e genera and f o u r s p e c i e s . No h y p o t h e s i s of r e l a t i o n s h i p i s g i v e n . Van der Land and Templeman (1968) r e c o g n i z e d the same t e n s p e c i e s c o n s i d e r e d v a l i d i n t h i s s t u d y . They d i v i d e d t h e s e s p e c i e s i n t o two genera, G y r o c o t y l o i d e s , c o n t a i n i n g a s i n g l e s p e c i e s , and G y r o c o t y l e , c o n t a i n i n g a l l of the r e m a i n i n g s p e c i e s . W i t h i n the genus G y r o c o t y l e , van der Land and Templeman (1968) r e c o g n i z e d two subgenera, G y r o c o t y l e , c o n t a i n i n g G y r o c o t y l e r u g o s a , and Amphiptyches c o n t a i n i n g a l l of the r e m a i n i n g s p e c i e s . From the p h y l o g e n e t i c a n a l y s i s i t i s c l e a r t h a t t h e r e need be o n l y one genus t o accommodate a l l of the known s p e c i e s of g y r o c o t y l i d s . I f G y r o c o t y l o i d e s i s r e t a i n e d , then G y r o c o t y l e becomes p a r a p h y l e t i c , or i f most of the s p e c i e s a r e p l a c e d i n the genus Amphiptyches (sensu Joyeux and Baer, 1951), then the 92 l a t t e r genus becomes p a r a p h y l e t i c . A l t h o u g h G y r o c o t y l o i d e s p o s s e s s e s a l a r g e number of autapomorphic t r a i t s i n comparison w i t h o t h e r s p e c i e s i n the group, t h e r e a r e n o n e t h e l e s s synapomorphic t r a i t s t o connect i t w i t h o t h e r g y r o c o t y l i d s p e c i e s . P r e v i o u s c l a s s i f i c a t i o n s have p l a c e d undue emphasis on the autapomorphic t r a i t s of t h i s s p e c i e s . HOST RELATIONSHIPS The p h y l o g e n e t i c r e l a t i o n s h i p s of the g y r o c o t y l i d s have been compared w i t h the p h y l o g e n e t i c r e l a t i o n s h i p s of h o l o c e p h a l a n f i s h e s . F i g u r e 41 shows the h y p o t h e s i z e d r e l a t i o n s h i p s of the g y r o c o t y l i d s , w i t h host names s u b s t i t u t e d f o r the p a r a s i t e names. The host i d e n t i t i e s were i n i t i a l l y t r e a t e d as c h a r a c t e r s , and the most p a r s i m o n i o u s t r a n s f o r m a t i o n s e r i e s were i d e n t i f i e d . The t r a n s f o r m a t i o n s e r i e s were then mapped onto the p a r a s i t e cladogram, as would be done w i t h a p r o b l e m a t i c c h a r a c t e r (see t a b l e I I I , Appendix B ) . The be s t f i t o b t a i n e d w i t h such a t r a n s f o r m a t i o n s e r i e s i s 6/9, or 67%. One of the b e s t f i t t i n g t r a n s f o r m a t i o n s e r i e s was then redrawn as a h y p o t h e s i s of p h y l o g e n e t i c r e l a t i o n s h i p f o r the h o s t s . T h i s phylogeny was then c o n v e r t e d i n t o a b i n a r y m a t r i x and the component t r a n s f o r m a t i o n s e r i e s were mapped onto the p a r a s i t e cladogram (see f i g . 4 2 ) . The f i t o b t a i n e d i n t h i s manner i s 50% (10/20). A t h i r d t e s t of t h e h y p o t h e s i s of r e l a t i o n s h i p was made by 93 comparing the g y r o c o t y l i d phylogeny t o a c u r r e n t l y a c c e p t e d h y p o t h e s i s of r e l a t i o n s h i p f o r the h o l o c e p h a l a n f i s h e s (from B i g e l o w and S c h r o e d e r , 1953). The comparison was made by drawing a cladogram c o r r e s p o n d i n g t o the key p r e s e n t e d by t h e s e a u t h o r s (see f i g . 4 3 ) . A b i n a r y m a t r i x d e s c r i b i n g the t r e e was then c o n s t r u c t e d and the component t r a n s f o r m a t i o n s e r i e s once a g a i n mapped onto the p a r a s i t e t r e e . The f i t o b t a i n e d i n t h i s c omparison i s 11/25, or 44%. S e v e r a l i n t e r e s t i n g c o n c l u s i o n s can be drawn from the t e s t s of the h y p o t h e s i s of c o e v o l u t i o n . F i r s t , s l i g h t l y more than h a l f of the a s s o c i a t i o n s between g y r o c o t y l i d s and t h e i r h o s t s can be e x p l a i n e d by c o e v o l u t i o n . In a d d i t i o n , h o s t t r a n s f e r s , which account f o r the r e m a i n i n g a s s o c i a t i o n s , i n most cases r e p r e s e n t r e c o l o n i z a t i o n s of p l e s i o m o r p h i c h o s t s . T h i s p r o b a b l y a l s o e x p l a i n s the b e t t e r f i t o b t a i n e d w i t h the host t r a n s f o r m a t i o n s e r i e s than w i t h t h e host p h y l o g e n i e s . The t r a n s f o r m a t i o n s e r i e s d e s c r i b e s the sequence of a c q u i s i t i o n of h o s t s p e c i e s , which may not always r e f l e c t the p h y l o g e n e t i c r e l a t i o n s h i p s of the h o s t s p e c i e s . In a l l t h r e e t e s t s of the h y p o t h e s i s of c o e v o l u t i o n , host t r a n s f e r s were c o n c e n t r a t e d i n one a r e a of the t r e e (see f i g s . 41-43). E v i d e n c e f o r c o l o n i z a t i o n i s found o n l y f o r s p e c i e s i n t h e upper h a l f of the t r e e . Thus, the h y p o t h e s i s of an i n i t i a l s p e c i a t i o n event d i v i d i n g the g y r o c o t y l i d e a n s i n t o two l i n e a g e s w hich s u b s e q u e n t l y c o e v o l v e d w i t h t h e h o l o c e p h a l a n h o s t s (see Van der Land and D i e n s k e , 1968; van der Land and Templeman, 1968; Simmons, 1974) i s not t e n a b l e . I n s t e a d the r e s u l t s of the 94 p h y l o g e n e t i c a n a l y s i s i n d i c a t e t h a t an i n i t i a l phase of c o e v o l u t i o n was f o l l o w e d by a phase i n which new h o s t s were a c q u i r e d p r i m a r i l y by c o l o n i z a t i o n . The h y p o t h e s i s t h a t the more common s p e c i e s i n each h o s t a r e more c l o s e l y r e l a t e d t o each o t h e r than t o the l e s s common s p e c i e s i n the same host has been c o r r o b o r a t e d , e x c e p t i n t h e case of the p a r a s i t e s of C a l l o r h i n c h u s c a l l o r h y n c h u s . G y r o c o t y l e rugosa i s more common than G y r o c o t y l e maxima, a l t h o u g h the l a t t e r i s more c l o s e l y r e l a t e d t o the o t h e r common s p e c i e s such as G y r o c o t y l e urna and G. f i m b r i a t a . W i t h the e x c e p t i o n of the two g y r o c o t y l i d s p e c i e s i n C a l l o r h i n c h u s c a l l o r h y n c h u s , the more common s p e c i e s a r e a l s o t h e more r e c e n t l y a c q u i r e d s p e c i e s . I t would be i n t e r e s t i n g t o reexamine specimens of H y d r o l a g u s o g i l b y i , t o see i f a second s p e c i e s i s p r e s e n t i n t h i s h o s t t o o . I t i s i n t e r e s t i n g t h a t a b e t t e r f i t i s o b t a i n e d f o r the ho s t phylogeny p r e d i c t e d from the p a r a s i t e r e l a t i o n s h i p s than f o r t he a c c e p t e d h y p o t h e s i s of h o s t r e l a t i o n s h i p s . Two e x p l a n a t i o n s f o r t h i s c o u l d be o f f e r e d . I t may be t h a t the host c l a s s i f i c a t i o n i s not n a t u r a l . A l t e r n a t i v e l y , i t may i n d i c a t e t h a t g y r o c o t y l i d s a r e not a good i n d i c a t o r of host r e l a t i o n s h i p s . I t i s p o s s i b l e t o c o n s t r u c t a t e s t t o choose between t h e s e two e x p l a n a t i o n s . A f o r m a l and e x p l i c i t h y p o t h e s i s of p h y l o g e n e t i c r e l a t i o n s h i p f o r the h o l o c e p h a l a n s would a s s i s t i n c h o o s i n g between t h e two p o s s i b i l i t i e s . A l t e r n a t i v e l y , i f p h y l o g e n e t i c a n a l y s e s of o t h e r p a r a s i t e s of h o l o c e p h a l a n f i s h e s were done, a h o s t phylogeny c o u l d be c o m p i l e d from a l l of the s y m b i o t i c a s s o c i a t i o n s as e s t a b l i s h e d 95 by Brooks (1981). P o s s i b l e c a n d i d a t e s f o r such a study would be monogeneans of the f a m i l y C h i m a e r i c o l i d a e , and copepods of the genus Vanbenedenia. BIOGEOGRAPHY The b i o g e o g r a p h i c r e l a t i o n s h i p s of the g y r o c o t y l i d s have a l s o been a n a l y z e d u s i n g the methods of v i c a r i a n c e b i o g e o g r a p h y , as d e s c r i b e d i n c h a p t e r 2. In f i g u r e 46, the p h y l o g e n e t i c r e l a t i o n s h i p s of the g y r o c o t y l i d s a r e shown, w i t h g e o g r a p h i c l o c a l i t i e s s u b s t i t u t e d f o r the s p e c i e s names. The d i s t r i b u t i o n of the g y r o c o t y l i d s can be d e s c r i b e d as a m p h i - A t l a n t i c and a m p h i - P a c i f i c . G y r o c o t y l i d s a r e n o t i c e a b l y absent from t r o p i c a l w a t e r s . L i k e the p a t t e r n of host a s s o c i a t i o n s , the b i o g e o g r a p h i c d i s t r i b u t i o n c o n t a i n s an apparent r e p e a t . H o l o c e p h a l a n f i s h e s a r e e x c l u s i v e l y m a r i n e , a l t h o u g h C a l l o r h i n c h u s c a l l o r h y n c h u s i s o c c a s i o n a l l y found i n e s t u a r i e s ( B i g e l o w and Schr o e d e r , 1953). A marine d i s t r i b u t i o n p r o v i d e s fewer o b s t a c l e s t o d i s p e r s a l than do e i t h e r f r e s h w a t e r or t e r r e s t r i a l e n v i r o n m e n t s . In a d d i t i o n , f a r l e s s i s known of the h i s t o r i c a l geology of t h e oceans (see Ne l s o n and P l a t n i c k , 1984 f o r a b r i e f review of t h i s p r o b l e m ) . A c c o r d i n g t o D i e t z and Holden (1971), the P a c i f i c Ocean i s the o l d e s t of the t h r e e oceans, h a v i n g s u r r ounded Pangaea. R i f t i n g d i v i d e d Pangaea i n t o L a u r a s i a and Gondwana, and s i m u l t a n e o u s l y opened t h e A t l a n t i c and I n d i a n Oceans. T h i s 96 model of the o r i g i n s of the t h r e e oceans i s somewhat p a r a d o x i c a l , as the maximum age of the ocean f l o o r sediments of a l l t h r e e oceans i s the same (see N e l s o n and P l a t n i c k , 1984, f o r a b r i e f r e v iew of t h i s problem and i t s i m p l i c a t i o n s f o r b i o g e o g r a p h y ) . The e x p l a n a t i o n u s u a l l y g i v e n i s t h a t s u b d u c t i o n removes the o l d e r s e d i m e n t s ; d i s s e n t i n g o p i n i o n s can be found, however (see Nelson and P l a t n i c k , 1984). Because the h i s t o r i c a l r e l a t i o n s h i p s of the oceans a r e u n c e r t a i n , no comparison of the p a r a s i t e r e l a t i o n s h i p s w i t h the a r e a r e l a t i o n s h i p s as d e t e r m i n e d from h i s t o r i c a l geology has been made. Two o t h e r q u a n t i t a t i v e c o m p a r i s o n s of the p a r a s i t e and a r e a r e l a t i o n s h i p s have been made, however. F i r s t , the most p a r s i m o n i o u s t r a n s f o r m a t i o n s e r i e s d e s c r i b i n g the a s s o c i a t i o n s between g y r o c o t y l i d s and the a r e a s they i n h a b i t was i d e n t i f i e d and mapped onto the p a r a s i t e t r e e (see f i g u r e 4 4 ) . The f i t o b t a i n e d i n t h i s manner i s 62.5% ( 5 / 8 ) . A second comparison was made by d r a w i n g an a rea c l a d o g r a m f o r the t r a n s f o r m a t i o n s e r i e s i n f i g u r e 44. The a r e a c l a d o g r a m was then c o n v e r t e d i n t o a b i n a r y m a t r i x (Appendix b, t a b l e I I I ) , aod the component c h a r a c t e r s t a t e s were mapped onto the p a r a s i t e p h ylogeny. The c o n s i s t e n c y index o b t a i n e d i n t h i s case was s l i g h t l y l o w e r , a t 50% ( 1 0 / 2 0 ) . Thus, the f i t of b o t h hypotheses of a r e a r e l a t i o n s h i p t o a h y p o t h e s i s of p h y l o g e n e t i c r e l a t i o n s h i p f o r the g y r o c o t y l i d s i s f a i r l y p o o r , even though the a rea c l a d o g r a m i s d e r i v e d from the g y r o c o t y l i d r e l a t i o n s h i p s . T h i s i n d i c a t e s t h a t e x t e n s i v e 97 d i s p e r s a l has o c c u r r e d . I t i s i n t e r e s t i n g , t o o , t h a t the d i s p e r s a l e v e n t s a r e c o n c e n t r a t e d i n the upper h a l f of the b r a n c h i n g diagram, as were the c o l o n i z a t i o n e v e n t s (see p r e v i o u s s e c t i o n ) . T h i s s u g g e s t s t h a t t h e r e has been a c o r r e l a t i o n between the two p r o c e s s e s . Sampling e r r o r c o u l d a c c o u n t f o r some of the a n o m a l i e s i n t h e d i s t r i b u t i o n s of the g y r o c o t y l i d s i n e i t h e r of two ways. F i r s t , the h a b i t s and d i s t r i b u t i o n s of the h o l o c e p h a l a n f i s h e s a r e p o o r l y known. The a r e a s which have the g r e a t e s t d i v e r s i t y of h o l o c e p h a l a n f i s h e s a r e a r e a s of heavy commercial f i s h i n g as w e l l as c e n t e r s f o r s c i e n t i f i c r e s e a r c h (Japan and Western Europe, f o r example). G y r o c o t y l i d s a r e c o n c e n t r a t e d i n t h e s e a r e a s . I t i s l i k e l y , t h e n , t h a t the d i s t r i b u t i o n of the g y r o c o t y l i d s r e f l e c t s i n p a r t the i n t e r e s t i n the group. Manter (1955) examined t h e d i s t r i b u t i o n p a t t e r n s of trematodes p a r a s i t i z i n g deepwater f i s h e s and c o n c l u d e d t h a t a m p h i - A t l a n t i c and a m p h i - P a c i f i c d i s t r i b u t i o n s can be a r t i f a c t s of the s a m p l i n g methods. He o b s e r v e d t h a t p a r a s i t e s d e s c r i b e d as absent i n the t r o p i c s may i n f a c t be p r e s e n t , but a t g r e a t e r d e p t h s . The l i k e l i h o o d of f i n d i n g t h e s e p a r a s i t e s i s t h e r e f o r e much l e s s . C e r t a i n l y , l e s s i s known of g y r o c o t y l i d s p a r a s i t i z i n g deepwater c h i m a e r o i d s such as H y d r o l a g u s a f f i n i s and R h i n o c h i m a e r a a t l a n t i c a (Hogans and H u r l b u t , 1984). A p o s s i b l e e x p l a n a t i o n f o r the d i s t r i b u t i o n of the g y r o c o t y l i d s i s t h a t the group i s pre-Pangaean, w i t h h o l o c e p h a l a n f i s h e s and t h e i r g y r o c o t y l i d p a r a s i t e s o c c u r r i n g i n the ocean s u r r o u n d i n g Pangaea. An i n i t i a l phase of c o e v o l u t i o n 98 was f o l l o w e d by a phase of c o l o n i z a t i o n and e x t e n s i v e d i s p e r s a l , b o th phases p r e c e d i n g the break-up of Pangaea. The g e o g r a p h i c d i s t r i b u t i o n s of the a m p h i l i n i d s (see c h a p t e r 2) r e f l e c t the break-up of Pangaea. S i n c e the g y r o c o t y l i d s a r e the s i s t e r group of the c e s t o i d e a n s , they would appear t o be o l d e r than e i t h e r of th e s e groups. S i n c e marine d i s t r i b u t i o n s may show e v i d e n c e of p l a t e movement (see B r u s c a , 1984; Thomson, 1981), the absence of e v i d e n c e of p l a t e movement i n t he d i s t r i b u t i o n of the g y r o c o t y l i d s i s s u g g e s t i v e of an o l d e r d i s t r i b u t i o n . H o l o c e p h a l a n f i s h e s and t h e i r p a r a s i t e s c o u l d p o t e n t i a l l y p r o v i d e a d d i t i o n a l i n f o r m a t i o n about pre-Pangaean marine l i f e , and about the h i s t o r i c a l g e ology of the oceans. In such a s t u d y , however, i t would be h e l p f u l t o examine a d d i t i o n a l h o l o c e p h a l a n s p e c i e s , such as Chimaera cubana from the West I n d i e s and a number of P a c i f i c s p e c i e s (see B i g e l o w and S c h r o e d e r , 1953) f o r g y r o c o t y l i d p a r a s i t e s . Some knowledge of the host s p e c i f i c i t y of g y r o c o t y l i d s would a l s o be h e l p f u l . At the moment, however, an i n v e s t i g a t i o n of the s p e c i f i c i t y of the a s s o c i a t i o n s i s not f e a s i b l e . The g y r o c o t y l i d l i f e c y c l e i s unknown and h o l o c e p h a l a n s do not s u r v i v e f o r l o n g p e r i o d s of time i n c a p t i v i t y . 99 IV. GENERAL DISCUSSION RECIPROCAL ILLUMINATION The term ' r e c i p r o c a l i l l u m i n a t i o n ' was i n t r o d u c e d by Hennig (1966) t o d e s c r i b e the manner i n which the r e s u l t s of a p h y l o g e n e t i c a n a l y s i s can be used t o shed l i g h t on the d a t a used i n t h a t a n a l y s i s . R e c i p r o c a l i l l u m i n a t i o n i s based on the i d e a t h a t s c i e n t i f i c r e s e a r c h c o n s i s t s of t e s t i n g and r e t e s t i n g h y potheses i n o r d e r t o o b t a i n c l o s e r and c l o s e r a p p r o x i m a t i o n s of the t r u t h ( W i l e y , 1981). The p h y l o g e n e t i c . a n a l y s e s of the a m p h i l i n i d e a n s and g y r o c o t y l i d e a n s were an outgrowth of a p h y l o g e n e t i c a n a l y s i s of the Subphylum C e r c o m e r i a (Brooks e t a l . , 1985a), and the h y p o t h e s i s of p h y l o g e n e t i c r e l a t i o n s h i p f o r the c e r c o m e r i a p r o v i d e d a b a s i s f o r the s e two s t u d i e s . The r e s u l t s of the p h y l o g e n e t i c a n a l y s i s of the a m p h i l i n i d e a n s and g y r o c o t y l i d e a n s have i n t u r n p r o v i d e d new su p p o r t f o r the h y p o t h e s i s of r e l a t i o n s h i p f o r the c e r c o m e r i a . A d d i t i o n a l c h a r a c t e r s d i s c o v e r e d i n t h i s s tudy have been mapped onto the p h y l o g e n e t i c t r e e o b t a i n e d by Brooks and coworkers (see f i g . 4 9 ) . A t o t a l of f o u r t e e n new c h a r a c t e r s have been i d e n t i f i e d (see f i g u r e 4 1 ) . A l l of t h e s e c h a r a c t e r s s u p p o r t the c l a s s i f i c a t i o n of Brooks e_t a_l. ( 1985a). When the new c h a r a c t e r s o b t a i n e d i n t h i s study and t h e new c h a r a c t e r s 100 o b t a i n e d i n a p h y l o g e n e t i c a n a l y s i s of t h e digeneans (Brooks et a l . , 1985b) a r e added t o the a n a l y s i s of the C e r c o m e r i a , a c o n s i s t e n c y index of 97% (70/72) i s o b t a i n e d . The new c h a r a c t e r s i d e n t i f i e d i n my study c o m p r i s e two groups, those w h i c h s u p p o r t the monophyly of the g y r o c o t y l i d e a ( c h a r a c t e r s 6-9, F i g u r e 45) or the a m p h i l i n i d e a ( c h a r a c t e r s 12-14, F i g u r e 4 7 ) , and t h o s e which s u p p o r t h i g h e r l e v e l g r o u p i n g s . These l a t t e r seven c h a r a c t e r s a r e d e s c r i b e d below. (1) Body shape. An e l o n g a t e , f l a t t e n e d body was found t o be a synapomorphy f o r the C e s t o d a r i a ( s e n s u B r o o k s , 1982). (2) Body s i z e . L a r g e body s i z e i n comparison w i t h most o t h e r p l a t y h e l m i n t h s was found t o be a synapomorphy f o r the C e s t o d a r i a (sensu B r o o k s , 1982). (3) T e s t i c u l a r bands. The presence of f o l l i c u l a r t e s t e s l y i n g i n bands on e i t h e r s i d e of the body was found t o be a synapomorphy f o r the Cercomeromorphae Bychowsky, 1937. (4) Ovary shape. The p r e s e n c e of a b i l o b e d f o l l i c u l a r o vary was found t o be a synapomorphy f o r e i t h e r the cercomeromorphs or f o r the c e s t o d a r i a n s . (5) U t e r i n e c o n f o r m a t i o n . The p r e s e n c e of a s i n u o u s u t e r u s i s a synapomorphy f o r the c e s t o d a r i a n s . 101 (6) Arrangement of the U t e r u s , T e s t e s and V i t e l l a r i a . The presence of a c o i l e d u t e r u s , w i t h a band of f o l l i c u l a r t e s t e s on e i t h e r s i d e , and bands of v i t e l l i n e f o l l i c l e s o u t s i d e of the t e s t e s was found t o be a synapomorphy f o r the c e s t o i d e a n s . (7) S p a t i a l r e l a t i o n s of the g e n i t a l d u c t s . The o r i e n t a t i o n of the g e n i t a l d u c t s d e p i c t e d i n f i g u r e 8a was found t o be a synapomorphy f o r the c e s t o i d e a n s . THE BIOLOGY OF RELICT GROUPS A m p h i l i n i d e a n s and g y r o c o t y l i d e a n s have t r a d i t i o n a l l y been r e g a r d e d as r e l i c t g roups. Watson (1911), f o r example, noted t h a t the two groups c o u l d be e i t h e r t h e remnants of groups which were once more w i d e s p r e a d , or groups which have simpy undergone r e l a t i v e l y l i t t l e d i v e r s i f i c a t i o n . To d a t e , however, no attempt has been made t o compare the two groups or t o attempt t o d i s t i n g u i s h between the two a l t e r n a t i v e h y p o t h e s e s f o r both groups s i m u l t a n e o u s l y . . The word ' r e l i c t ' has a number of c o n n o t a t i o n s . Simpson (1944) remarked t h a t " t h i s innocuous word has been i n v o l v e d i n an o u s t a n d i n g l y g r e a t c o n f u s i o n of i d e a s and c l a s h of t h e o r i e s . " I t i s t h e r e f o r e w o r t h w h i l e t o c o n s i d e r d i f f e r e n t usages of the word r e l i c t . Most a u t h o r s (see Seddon, 1971, f o r example) 102 d i s t i n g u i s h between e c o l o g i c a l r e l i c t s , s p e c i e s l i v i n g i n r e f u g i a , and e v o l u t i o n a r y r e l i c t s , u s u a l l y d e f i n e d as groups which were once d i v e r s e and a r e now l e s s so. Simpson (1944) i d e n t i f i e d f o u r t y p e s of e v o l u t i o n a r y r e l i c t s . These a r e : (1) n u m e r i c a l r e l i c t s , groups which were once numerous and ar e now r e s t r i c t e d ; (2) g e o g r a p h i c r e l i c t s , groups which were once wides p r e a d and now a r e r e s r i c t e d i n d i s t r i b u t i o n ; (3) taxonomic r e l i c t s , groups e x h i b i t i n g a lower degree of d i v e r s i t y than they d i d p r e v i o u s l y ; and (4) p h y l o g e n e t i c r e l i c t s , a n c i e n t groups p e r s i s t i n g r e l a t i v e l y unchanged. As Simpson n o t e d , a p a r t i c u l a r o r g a n i s m may f i t i n t o more than one of t h e s e c a t e g o r i e s , but need not f i t i n t o more than one i n o r d e r t o be c o n s i d e r e d a r e l i c t . T r a d i t i o n a l l y , a h y p o t h e s i s of r e l i c t s t a t u s has been based on e v i d e n c e o b t a i n e d from f o s s i l s . In the absence of a f o s s i l r e c o r d , c o r r o b o r a t i o n of hypotheses of r e l i c t s t a t u s has come from d i s j u n c t b i o g e o g r a p h i c d i s t r i b u t i o n s and m o r p h o l o g i c a l p e c u l i a r i t i e s . A n a l y s i s of b i o g e o g r a p h i c d i s t r i b u t i o n s u s i n g the methods of v i c a r i a n c e biogeography and of s y m b i o t i c a s s o c i a t i o n s u s i n g Hennig's p a r a s i t o l o g i c a l method o f f e r a p o t e n t i a l means of t e s t i n g h ypotheses of r e l i c t s t a t u s i n a more r i g o r o u s manner. P o t e n t i a l g e o g r a p h i c r e l i c t s can be i d e n t i f i e d by examining 103 the r o l e of v i c a r i a n c e i n the o r i g i n of t h e i r g e o g r a p h i c d i s t r i b u t i o n . S i n c e d i s p e r s a l by d e f i n i t i o n i m p l i e s t h a t the range of t h e group has i n c r e a s e d , e v i d e n c e of widespead d i s p e r s a l f a l s i f i e s a h y p o t h e s i s of r e l i c t s t a t u s . E v i d e n c e of v i c a r i a n c e , on the o t h e r hand, p r o v i d e s some c o r r o b o r a t i o n f o r a h y p o t h e s i s of r e l i c t s t a t u s . N u m e r i c a l and p h y l o g e n e t i c r e l i c t s can be i d e n t i f i e d u s i n g Hennig's p a r a s i t o l o g i c a l method ( B r o o k s , 1979, 1981). I f h o s t s and p a r a s i t e s show e v i d e n c e of h a v i n g c o e v o l v e d , then i t may be p o s s i b l e t o i n f e r the h i s t o r i c a l e c o l o g y of the p a r a s i t e s from knowledge of the h o s t s . A p a r a s i t e taxon c o u l d be i d e n t i f i e d as a p h y l o g e n e t i c r e l i c t i f i t e x h i b i t s a low degree of d i v e r s i t y and i f i t appears t o have c o e v o l v e d w i t h a hos t taxon of s i m i l a r l y low d i v e r s i t y . I d e n t i f i c a t i o n of a n u m e r i c a l r e l i c t , on the o t h e r hand would r e q u i r e e v i d e n c e of c o e v o l u t i o n of a p a r a s i t e t axon e x h i b i t i n g a low degree of d i v e r s i t y w i t h a more d i v e r s e h o s t t a x o n . When a s m a l l p a r a s i t e taxon i s a s s o c i a t e d w i t h a l a r g e and s p e c i o s e h o s t t a x o n , i t i s n e c e s s a r y t o q u e s t i o n whether c o e v o l u t i o n i s a r e a s o n a b l e e x p l a n a t i o n . There may be complete congruence of the hos t and p a r a s i t e t r e e s , but because the p a r a s i t e s a r e absent from many of the h o s t t a x o n , i t i s n e c e s s a r y t o e x p l a i n t h e s e absences. The i n t e n t i o n , t h e n , i s t o i d e n t i f y the. e x p l a n a t i o n r e q u i r i n g the fewest ad hoc a s s e r t i o n s . Low p a r a s i t e d i v e r s i t y and h i g h h o s t d i v e r s i t y c o u l d o c c u r i n c o e v o l v e d symbionts i n at l e a s t two ways. Ho s t s may become e x t i n c t , and t h e i r p a r a s i t e s 104 become e x t i n c t a l s o . A l t e r n a t i v e l y , p a r a s i t e s may be absent from e x t a n t h o s t s which have undergone e v o l u t i o n a r y changes i n c o m p a t i b l e w i t h s u r v i v a l of the p a r a s i t e s . S i n c e p a r a s i t e s cannot s u r v i v e and reproduce w i t h o u t a h o s t , they cannot d i s a p p e a r and reappear i n the way t h a t a m o r p h o l o g i c a l c h a r a c t e r c a n . C o e v o l u t i o n t h e r e f o r e i m p l i e s r e t e n t i o n of the p a r a s i t e s i n a t l e a s t the a n c e s t r a l t a x a . I t i s not p o s s i b l e t o i d e n t i f y taxonomic r e l i c t s , however, as a l t h o u g h i t i s p o s s i b l e t o r e c o g n i z e t h a t a n c e s t r a l t a x a must have r e t a i n e d members of a p a r a s i t e t a x o n , i t i s not p o s s i b l e t o e s t a b l i s h the number of s p e c i e s i n v o l v e d . By t h e s e c r i t e r i a , a m p h i l i n i d e a n s appear t o be g e o g r a p h i c and n u m e r i c a l r e l i c t s . T h e i r g e o g r a p h i c d i s t r i b u t i o n can be e x p l a i n e d e n t i r e l y by v i c a r i a n c e . In a d d i t i o n , a m p h i l i n i d e a n s appear t o have c o e v o l v e d w i t h the t e l e o s t s , a l t h o u g h many t e l e o s t s do not harbor a m p h i l i n i d e a n s . G y r o c o t y l i d e a n s , on the o t h e r hand appear t o be p h y l o g e n e t i c r e l i c t s . A l t h o u g h c o e v o l u t i o n can e x p l a i n o n l y some of the a s s o c i a t i o n s between g y r o c o t y l i d s and h o l o c e p h a l a n s , r e m a i n i n g a s s o c i a t i o n s a r e r e c o l o n i z a t i o n s of p l e s i o m o r p h i c h o s t s . 105 LITERATURE CITED A l l i s o n , F. R. and C o a k l e y , A. 1973.The two s p e c i e s of G y r o c o t y l e i n the e l e p h a n t f i s h , C a l l o r h y n c h u s m i l i i ( B o r y ) . J . Roy. Soc. New Z e a l a n d . 3(3) ~ 3 8 1 - 3 9 2 . A u d l e y - C h a r l e s , M. G. 1978. The I n d o n e s i a n & P h i l i p p i n e A r c h i p e l a g o s . M o u l l a d e , M.; N a i r n , A. E. M. eds. The P h a n e r o z o i c Geology of the W o r l d : The M e s o z o i c . E l s e v i e r P u b l . Co. Amsterdam. V o l 2, p a r t A: 165-207. A x e l r o d , D. I . 1972. P l a t e T e c t o n i c s and problems of angiosperm h i s t o r y . XVII Congres I n t e r n a t i o n a l de Zoology. Theme No 1 B i o g e o g r a p h i e e t l i a s i o n s i n t e r c o n t i n e n t a l e s au c o u r s du Mesozoique. pp. 1-16. B i g e l o w , H. B. and S c h r o e d e r , W. C. 1953. C h i m a e r o i d s . F i s h e s of the Western N o r t h A t l a n t i c . Memoir. Sea r s F o u n d a t i o n f o r M a r i n e R e s e a r c h No. 1, p a r t I I . Y a l e U n i v e r s i t y , New Haven. B r o o k s , D. R. 1979. T e s t i n g the c o n t e x t and e x t e n t of h o s t p a r a s i t e c o e v o l u t i o n . S y s t . Z o o l . 2 8 ( 3 ) : 299-307. B r o o k s , D. R. 1981. Hennig's p a r a s i t o l o g i c a l method: a proposed s o l u t i o n . S y s t . Z o o l . 3 0 ( 3 ) : 229-249. B r o o k s , D. R. 1982. H i g h e r l e v e l c l a s s i f i c a t i o n of p a r a s i t i c p l a t y h e l m i n t h s and fundamentals of c e s t o d e c l a s s i f i c a t i o n . Pages 189-193 i n M e t t r i c k , D. F.; D e s s e r , S. S. eds. P a r a s i t e s - T h e i r World and Ours. E l s e v i e r B i o m e d i c a l , Amsterdam. 465 pp. B r o o k s , D. R., O'Grady, R. T. and G l e n , D. R. 1985a. Phylogeny of the C e r c o m e r i a . P r o c . Helm. Soc. Wash. 52:1-20. B r o o k s , D. R.; O'Grady, R. T.; G l e n , D. R. 1985b. P h y l o g e n e t i c a n a l y s i s of t h e Digenea ( P l a t y h e l m i n t h e s : C e r c o m e r i a ) w i t h comments on t h e i r a d a p t i v e r a d i a t i o n . Can. J . Z o o l . 63: 411-443. B r o o k s , D. R.; C a i r a , J . N.; P i a t t , T. R.; P r i t c h a r d , M. H. ( 1 9 8 4 ) , P r i n c i p l e s and Methods of P h y l o g e n e t i c S y s t e m a t i c s : a C l a d i s t i c s Workbook. S p e c i a l P u b l i c a t i o n no. 12, Museum of N a t u r a l H i s t o r y , U n i v e r s i t y of Kansas. 92 pp. B r u s c a , R. C. 1984. Phylogeny, e v o l u t i o n & biogeography of t h e marine i s o p o d S u b f a m i l y I d o t e i n a e ( C r u s t a c e a : Isopoda: I d o t e i d a e ) T r a n s a c t i o n s of the San Diego Soc. of Nat. H i s t . 20: 99-134. Bychowsky, B. E. 1957. Monogenetic t r e m a t o d e s : t h e i r 106 s y s t e m a t i c s and phylogeny. T r a n s l a t e d by H a r g i s , W. J . (A. I . B. S. t r a n s l a t i o n s ) . Akad. Nauk. S. S. S. R., Moscow. 627 pp. C o l b e r t , E. H. 1981. The d i s t r i b u t i o n of T e t r a p o d s & the break-up of Gondwana. C r e s s w e l l , M. M., V e l l a , P. and Balkema, A. A., eds. Gondwana F i v e . P r o c e e d i n g s of the 5 t h i n t e r n a t i o n a l Gondwana Symposium. Rotterdam, pp. 277-282. C o l e , N. C. 1968. M o r p h o l o g i c a l s t u d i e s on the c e s t o d a r i a . M. A. t h e s i s , U n i v e r s i t y of C a l i f o r n i a . C r a c r a f t , J . 1972. Faunas around the s o u t h e r n end of the w o r l d , pp. 1-35 XVII Congres i n t e r n a t i o n a l de Zoology. Theme No.1 B i o g e o g r a p h i e e t l i a s i o n s i n t e r c o n t i n e n t a l e s au c o u r s du Mesozoique. pp. 1-16. C r a c r a f t , J . 1983. C l a d i s t i c a n a l y s i s and b i o g eography: r e c o n s t r u c t i n g the p a t t e r n of e v o l u t i o n . Am. S c i e n t i s t . 7 1 ( 3 ) : 273-281. Craw, R. C ; Weston, P. 1984. Panbiogeography: a p r o g r e s s i v e r e s e a r c h program? S y s t . Z o o l . 3 3 ( 1 ) : 1-13. Dienske,H. 1968. A s u r vey of the Metazoan p a r a s i t e s of the R a b b i t - f i s h , Chimaera Monstrosa L. ( H o l o c e p h a l i ) . N e t h e r l a n d s J o u r n a l of Sea R e s e a r c h . 4 ( 1 ) : 32-58. D i e t z , R. S.; H olden, J . C. 1971. The breakup of Pangaea. i n C o n t i n e n t s A d r i f t . W.H.Freeman and Company, San F r a n s i s c o . pp. 102-113. D i e s i n g , K. M. 1850. Systema Helminthum. V i e n n a . V o l . I . i - x i v + 679 pp. D o l l f u s , R. Ph. 1922. L ' O r i e n t a t i o n , morphologique des G y r o c o t y l e e t des c e s t o d e s en g e n e r a l . B u l l . Soc. Z o o l . F r a n c e . 48: 203-242. Donges, J . ; H a r d e r , W. 1966. N e s o l e c i t h u s a f r i c a n u s n. sp. ( C e s t o d a r i a , A m p h i l i n d e a ) aus dem coelom von G_^  n i l o t i c u s C u v i e r , 1829 ( T e l e o s t e i ) . Z. f . P a r a s i t . 28: 125-141. D u b i n i n a , M. N. 1960. Morphology of A m p h i l i n i d a e ( C e s t o d a r i a ) i n c o n n e c t i o n w i t h t h e i r p o s i t i o n i n the f l a t w o r m system. Doklady AN, SSSR. 135(2): 501-504 (A.I.B.S. t r a n s l a t i o n , pp.943-945.) D u b i n i n a , M. N. 1962. C l a s s C e s t o i d e a . P a v l o v s k i y , E. N. ed. Key t o P a r a s i t e s of F r e s h w a t e r F i s h e s of the U.S.S.R. T r a n s l a t e d by B i r r o n , A.; C o l e , Z. S., I s r e a l Program f o r S c i . T r a n s l a t i o n s . J e r u s a l e m , 1964. 107 D u b i n i n a M. N. 1978. Fla t w o r m s of the A m p h i l i n i d a C l a s s ( S u b s t a n t i a t i o n & Syst e m ) . 4 t h ICOPA meetings Aug. 19-26, 1978 Warsaw. Short Communications, S e c t . B. pp. 29-30. D u b i n i n a , M. N. 1982. P a r a s i t i c Worms of the C l a s s A m p h i l i n i d a ( P l a t y h e l m i n t h e s ) Trudy Z o o l o g i c h e s k o g o I n s t i t u t a , L e n i n g r a d . 100, 144 pp. D u j a r d i n , F. 1845. H i s o t o i r e n a t u r e l l e des h e l m i n t h e s ou v e r s i n t e s t i n a u x . 654 pp. [ i n Braun, 1889]. F a r r i s , J . S. 1970. Methods f o r computing Wagner t r e e s . S y s t . Z o o l . 19: 83-92 Fuhrmann, 0. 1931. D r i t t e K l a s s e des Cladus P l a t h e l m i n t h e s . C e s t o i d e a . i n : K u k e n t h a l s ' s Handbuch der Z o o l o g i e v o l . 2: 141-146. G o s l i n e , W. A. 1972. A r e - e x a m i n a t i o n of the s i m i l a r i t y between the f r e s h w a t e r f i s h e s of A f r i c a and South America. XVII c o n g r e s s i n t e r n a t i o n a l de Zoology. Theme No. 1 B i o g e o g r a p h i e e t l i a s i o n s i n t e r - c o n t i n e n t a l e s au c o u r s due Mesozoique. Goto, S. ; I s h i i , N. 1936. On a new ces t o d e s p e c i e s . A m p h i l i n a j a p o n i c a . Japanese J . Exp. MED/14: 81-83. G r a n t , E. M. 1982. Guide t o F i s h e s , 5 th ed. Department of Harbours and M a r i n e . B r i s b a n e , Queensland. W i l k e P r i n t e r s . ( 1 s t ed. 1965) Grimm, 0. 1871. Zur Anatomie der Binnenwurmer. Z e i t . w i s s . Z o o l . Bd. XXI. p. 499. H a l v o r s e n , O.; W i l l i a m s , H. H. 1968. S t u d i e s of t h e H e l m i n t h Fauna of Norway, IX. G y r o c o t y l e : ( P l a t y h e l m i n t h e s ) i n Chimaera monstrosa from O s l o F j o r d . N y t t Magasin f o r Z o o l o g i . 15: 130-142. H a s w e l l , W. .A. 1902. On a G y r o c o t y l e from Chimaera o g i l b y i and on G y r o c o t y l e i n g e n e r a l . P r o c . L i n n . Soc. New South Wales 27: 48-54. Hennig, W. 1966. P h y l o g e n e t i c S y s t e m a t i c s . U n i v . I l l i n o i s P r e s s , Urbana. 263 pp. Hogans, W. E.; H u r l b u t , T. R. 1984. P a r a s i t e s of the k n i f e n o s e Chimaera, R h i n o c h i n a e r a a t l a n t i c a from the Northwest A t l a n t i c , Can. F i e l d N a t u r a l i s t 98 ( 3 ) : 365 Hu n g e r b u h l e r , M. 1910. S t u d i e n an G y r o c o t y l e n und Cestoden. E r g e b n i s s e e i n e r von L. S c h u l t z e a u s g e f u h r t e n Z o o l o g i s c h e n F o r s c h u n g s r e i s e i n S u d a f r i k a . J e n . Denkschr. 16: 495-522. 108 Hyman, L.H. 1951. The I n v e r t e b r a t e s V o l . 2 - P l a t y h e l m i n t h e s and R h y n c h o c o e l a . M c G r a w - H i l l , New York. 550 pp. 1 r e f ( * ) I h l e , J . E.; I h l e - L a n d e n b e r g , M. E. 1932. Ueber e i n e n neuen C e s t o d a r i e r R o s t e r i n a k u i p e r i n. gen. n. sp_.) aus e i n e r S c h i l d k r o t e . Z o o l . Anz. 100: 309-316. J a n i c k i , C. von. 1908. Ueber den bau von A m p h i l i n a l i g u l o i d e a D i e s i n g Z. Wis s . Z o o l . 89: 568-597. J a n i c k i , C. von 1928. Ueber d i e L e b e n s g e s c h i c h t e von A m p h i l i n a  f o l i a c e a dem P a r a s i t e n des W o l g a - S t e r l e t s , nach Beobachtungen und E x p e r i m e n t e n . N a t u r w i s s s . 16(44): 820-821 . J a n i c k i , C. von 1930. Ueber d i e j u n g s t e n Zustande von A m p h i l i n a f o l i a c e a i n der F i s c h l e i b e s h o h l e , sowie G e n e r a l l e s z u r A u f f a s s u n g des Genus A m p h i l i n a G. Wagen. Z o o l . Anz. 90: 190-205. J o h n s t o n , T. H. 1931. An a m p h i l i n i d from an A u s t r a l i a n t o r t o i s e . A u s t r a l . J . Exp. B i o l , and Med. S c i . 8:1-7. J o h n s t o n , T. H. 1934. Remarks on some A u s t r a l i a n C e s t o d a r i a . P r o c . L i n n . Soc. New South Wales 59: 66-70. J o h r i , G.N. 1959. On a remarkable new c a r y o p h y l l i d c e s t o d e , H u n t e r o i d e s m y s t e i gen et sp. nov. from a f r e s h water f i s h i n D e l h i S t a t e . Z e i t s c h r . f . P a r a s i t e n k u n d e . Bd. 19 ( 4 ) : 368-374. Joyeux, C ; Baer, J . G. 1950. Le genre G y r o c o t y l o i d e s Fuhrmann,1931 ( C e s t o d a r i a ) . B u l l . Soc. n e u c h a t e l . S c i . 73: 71-79. Joyeux, C ; Baer, J . C. 1951. Le genre G y r o c o t y l e D i e s i n g , 1 8 5 0 ( C e s t o d a r i a ) . Rev. S u i s s e Z o o l . 58: 371— 381 . Joyeux, C ; Baer, J . G. 1961. C l a s s e des C e s t o d a i r e s ( C e s t o d a r i a , M o n t i c e l l i ) . G r a s s e , P-P. ed. T r a i t e de Z o o l o g i e - Anatomie, S y s t e m a t i q u e , B i o l o g i e : P l a t y h e m i n t h e s , Mesozoares, A c a n t h o c e p h a l e s , N e m e r t i e n s . Tome 4. 944 pp. K h a l i l , L. F. 1977. Gyrometra kunduchi n. sp., a c e s t o d a r i a n from P l e c t o r h y n c h u s p i c t u s Thunberg,1792 from the I n d i a n Ocean. J . F i s h B i o l . , Vol.2,no.1:15-19. K o f o i d , C. A.; Watson, E. E. 1910. On the o r i e n t a t i o n of G y r o c o t y l e and of t h e c e s t o d e s t r o b i l a . Advance p r i n t from P r o c . 7 t h I n t e r n a t . Z o o l . C ongress, B o s t o n , 1907. 5 pp. 109 K r o y e r , H. N. 1852. Danmarks F i s k e . S. T r i e r s , Copenhagen. 3 ( p a r t 2 ) : 705-1279. Lauder, G. V.; Liem, K. F. 1983. The e v o l u t i o n and i n t e r r e l a t i o n s h i p s of the A c t i n o p t e r y g i a n f i s h e s . B u l l . Mus. Comp. Z o o l . , H a r v a r d U n i v . P r e s s . 150(3) 197 pp. L a u r i e , J . S. 1971. C a r b o h y d r a t e a b s o r p t i o n by G y r o c o t y l e  f i m b r i a t a and G y r o c o t y l e p a r v i s p i n o s a ( P l a t y h e l m i n t h e s ) . Exp. P a r a s i t . 29: 375-385. L i n t o n , E. 1924. G y r o c o t y l e p l a n a sp. nov., w i t h notes on South A f r i c a n c e s t o d e s of f i s h e s . F i s h . M a rine B i o l . Survey S. A f r i c a . Rep. 3, No. 8. 27 pp. L l w e l l y n , J . 1965. The e v o l u t i o n of p a r a s i t i c p l a t y h e l m i n t h s . T a y l o r , A. E. R. ed. 3rd Symposium, B r i t i s h Soc. P a r a s i t o l . B l a c k w e l l S c i e n t i f i c P u b l i c a t i o n s , O x f o r d , pp.47-78. Lonnberg, E. 1891. Anatomische s t u d i e n ueber S c a n d i n a v i s c h e Cestoden., v o l . 1 . Svenska V e t e n s k . Akad. Handl. 24(1):1-109. Lonnberg, E. 1897. B e i t r a g e zur p h y l o g e n i e der p a r a s i t i s c h e n P l a t h e l m i n t h e n . C e n t r a l b l . B a k t . 21:674-684. Luhe, M. 1910. Cestoden. B r a u e r , A., ed. D i e Susswasserfauna D e u t s c h l a n d s . H e f t 18, 1-153. [ i n S o u t h w e l l , 1928] L ynch, J . E. 1945. R e d e s c r i p t i o n of the s p e c i e s of G y r o c o t y l e from the r a t f i s h , H y d r o l a g u s c o l l e i (Lay and B e n n e t ) , w i t h n otes on the morphology and taxonomy of the genus. J . P a r a s i t o l . 31: 418-446. Lyons, K. M. 1966. The c h e m i c a l n a t u r e of and e v o l u t i o n a r y s i g n i f i c a n c e of monogenean attachment s c l e r i t e s . P a r a s i t o l o g y 56: 63-100. Lyons, K. M. 1969. The f i n e s t r u c t u r e of the body w a l l of G y r o c o t y l e u r n a . Z e i t s c h r . f . P a r a s i t e n k d . 33: 95-109. MacDonagh, E. J . 1927. P a r a s i t o s de peces c o m i s t i b l e s I I I . Dos c e s t o d a r i o s : G y r o c o t y l e rugosa d e l "Pez g a l l o " y G y r o c o t y l e maxima n. sp_. d e l "Gatuso".Sem. Med.,Buenos A i r e s . 34: 1232-1235. Maddison, W. P.; Donoghue, M. J . ; Maddison, D. R. 1984. Outgroup a n a l y s i s and parsimony. S y s t . Z o o l . 3 3 ( 1 ) : 83-103. Malmberg, G. 1974. On the l a r v a l p r o t o n e p h r i d i a l system of G y r o c o t y l e and the e v o l u t i o n of Cerceomeromorphae ( P l a t y h e l m i n t h e s ) . Z o o l . S c r i p t a . 3: 65-81. 110 Manter, H. W. 1951. S t u d i e s on G y r o c o t y l e rugosa D i e s i n g 1850, a c e s t o d a r i a n p a r a s i t e of the e l e p h a n t f i s h , C a l l o r h y n c h u s m i l i i . Z o o l . P u b l . V i c t o r i a U n i v . C o l l . , W e llington,New Z e a l a n d . 1 ( 1 7 ) : 1-11. Manter, H. W. 1953. G y r o c o t y l e , a p e c u l i a r p a r a s i t e of the e l e p h a n t f i s h i n New Ze a l a n d . T u a t a r a . 5 ( 2 ) : 49-51. Manter, H. W. 1955. The zoogeography of trematodes of marine f i s h e s . Exp. P a r a s i t . 4: 62-86. M e n d i v i l - H e r r e r a , J . 1946. G y r o c o t y l e meandrica n. sp. d e l i n t e s t i n o e s p i r a l d e l pez g a l l o , C a l l o r h y n c h u s  c a l l o r h y n c h u s ( L . ) . Commun. Z o o l . Mus. H i s t . Nat. Montevideo (36) v.2:1-12. M i c k e v i c h , M. 1981. Q u a n t i t a t i v e p h y l o g e n e t i c b i o geography. Funk, V. A.; Br o o k s , D. R. eds. Advances i n C l a d i s t i c s . P r o c . of the f i r s t meeting of the W i l l Hennig S o c i e t y . New York B o t a n i c a l Garden, N.Y. pp. 209-222. M i t t e r , C. E.; Brooks, D. R. 1983. P h y l o g e n e t i c a s p e c t s of c o e v o l u t i o n . Futuyuma, D. J . ; S l a t k i n , M. eds. C o e v o l u t i o n . S i n a u e r A s s o c i a t e s , I n c . Sunderland,Mass. Miyamoto, M. 1985. Consensus cladograms and g e n e r a l c l a s s i f i c a t i o n s . C l a d i s t i c s 1: 181-189. M o n t i c e l l i , F. S. 1889. Notes on some Entozoa i n the c o l l e c t i o n of the B r i t i s h Museum. P r o c . Z o o l . Soc. London, pp. 321-325. M o n t i c e l l i , F . S. 1892. A p p u n t i s u i C e s t o d a r i a . A t t i Accad. Sc. F i s . Mat. e Nat. N a p o l i . 5:1-11. N e l s o n , G.; P l a t n i c k , N. 1981. S y s t e m a t i c s and Biogeography : C l a d i s t i c s and V i c a r i a n c e . Columbia U n i v . P r e s s , New Yor k . N e l s o n , G.; P l a t n i c k , N. 1984. Biogeography. Head, J . J . ed. C a r o l i n a B i o l o g y R e a d i n g s . B u r l i n g t o n , N. Y. O l s s o n , P. 1896. Sur Chimaera monstrosa e t ses p a r a s i t e s . Mem. Soc. Z o o l . F r . 9: 499-512 P a u l i a n , R. 1972. La p o s i t i o n de Madagascar dans l e double probleme du peuplement a n i m a l e t des t r a n s l a t i o n s c o n t i n e n t a l e s . XVII Congres i n t e r n a t i o n a l de Zoology. Theme no.1 B i o g e o g r a p h i e e t l i a s o n i n t e r - c o n t i n e n t a l e s au c o u r s du Mesozoique. P l a t n i c k , N. I . 1979. P h i l o s o p h y and the t r a n s f o r m a t i o n of c l a d i s t i c s . S y s t . Z o o l . 28: 537-546. 111 Poche, F. 1922. Zur K e n n t n i s der A m p h i 1 i n i d e a . Z o o l . Anz. 54: 276-287. Poche, F. 1925. Zur K e n n t n i s von A m p h i l i n a f o l i a c e a . Z. Wiss. Zool.125: 585-619. Poche, F. 1926a. Das System der P l a t o d a r i a . A r c h . N a t u r g . 91: 241-458. Poche, F. 1926b. On the morphology and s y s t e m a t i c p o s i t i o n of the c e s t o d e , G i g a n t o l i n a magna ( S o u t h w e l l ) . Rec. I n d . Mus. 28: 1-27. P r i c e , C. E. 1967. The phylum P l a t y h e l m i n t h e s : a r e v i s e d c l a s s i f i c a t i o n . R i v . P a r a s i t o l . 28: 249-260. R i s e r , N. W. 1948. A m p h i l i n a b i p u n c t a t a n. sp., a N o r t h American C e s t o d a r i a n . J . P a r a s i t . 3 4 ( 6 ) : 479-485. Rohde, K.; G e o r g i , M. 1983. S t r u c t u r e and development of A u s t r a m p h i 1 i n a e l o n g a t a Johnston,1931 ( C e s t o d a r i a : A m p h i l i n i d e a ) . I n t . J . P a r a s i t o l . 13: 273-287. Rosen, D. E. 1978. V i c a r i a n t p a t t e r n s and h i s t o r i c a l e x p l a n a t i o n i n bio g e o g r a p h y . S y s t . Z o o l . 27: 159-188. R u d o l p h i , C. A. 1819. Entozoorum s y n o p s i s c u i accedent m a n t i s s a d u p l e x e t i n d i c e s l o c u p l e t i s s i m i . B e r o l i n i . 811pp. [ I n D i e s i n g , 1850]. R u s z k o w s k i , J . S. 1932. Etudes sur l e c y c l e e v o l u t i f e t sur l a s t r u c t u r e des c e s t o d e s de mer. I I . Sur l e s l a r v e s de G y r o c o t y l e urna (Gr. e t Wagen.). B u l l . I n t e r n . Akad. P o l o n . Sc. C l a s s e Sc. Math. Nat., s. B: Sc. Nat (7-10): 629-641. S a l e n s k y , W. 1874. Ueber den Bau und d i e E n t w i c k l u n g s g e s c h i c h t e der A m p h i l i n a (Monostoma f o l i a c e u m ) Rud. Z. Wiss. Z o o l . 24: 291-342. Seddon, B. 1971. I n t r o d u c t i o n t o Biogeography. G e r a l d Duckworth and Co. Ltd.,London. i - v i i i + 2 2 0 p p . Simmons, J . E. 1974. G y r o c o t y l e : a c e n t u r y of enigma. V e r n b e r g , W. N. ed. S y m b i o s i s i n the Sea. U n i v e r s i t y of South C a r o l i n a P r e s s . C o l u m b i a , South C a r o l i n a . Simmons, J . E.; L a u r i e , J . S. 1972. A stu d y of G y r o c o t y l e i n the San Juan a r c h i p e l a g o , Puget Sound, U.S.A., w i t h o b s e r v a t i o n s of the h o s t H y d r o l a g u s c o l l i e i (Lay and B e n n e t t ) . I n t . J . P a r a s i t . 2: 59-77. Simpson, G. G. 1944. Tempo and Mode i n E v o l u t i o n . Columbia 1 12 U n i v e r s i t y P r e s s , New Y ork. Spencer, W. B. 1889. The anatomy of Amphiptyches urna (Grube and Wagner). T r a n s . Roy. Soc. V i c t o r i a 1: 138-151. S o u t h w e l l , T. 1915. Notes from the Bengal F i s h e r i e s L a b o r a t o r y , I n d i a n Museum. No. 2. On some I n d i a n P a r a s i t e s of F i s h , w i t h a note on c a rcinoma i n t r o u t . Records I n d . Mus. 11: 311-330. S t u n k a r d , H. W. 1962. The o r g a n i z a t i o n , ontogeny, and o r i e n t a t i o n of the C e s t o d a . The Q u a r t e r l y Review of B i o l o g y 37: 23-24. T a r l i n g , D. H. 1981. Models f o r t h e f r a g m e n t a t i o n of Gondwana. C r e s s w e l l , M. M.; V e l l a , P., eds. Gondwana F i v e . P r o c e e d i n g s of the F i f t h I n t e r n a t i o n a l Gondwana Symposium, W e l l i n g t o n , New Z e a l a n d . Thomson, M. R. A. 1981. Mesozoic ammonite faunas of A n t a r c t i c a and the break-up of Gondwana. I b i d , pp. 269-275. van der Land, J . , and D i e n s k e , H. 1968. Two new s p e c i e s of G y r o c o t y l e (Monogenea) from c h i m a e r i d s ( H o l o c e p h a l i ) . Z o o l . Mededel., L e i d e n 43: 97-105. van der Land, J . , and Templeman, W. 1968. Two new s p e c i e s of G y r o c o t y l e (Monogenea) from H y d r o l a g u s a f f i n i s ( B r i t o C a p e l l o ) C H o l o c e p h a l i ) . J . F i s h . Res. Bd. Canada 25: 2365-85. van der Land, J . 1967. C r o b y l o p h o r u s K r o y e r , 1852 and C r o b y l o p h o r u s chimaerae K r o y e r , 1852, (Cestoda or Monogenea, G y r o c o t y l i d a ) : proposed s u p p r e s s i o n under the p l e n a r y powers. B u l l . Z o o l . Norn. 24: 123-125. von L i n s t o w , 0. F. B. 1901. E n t o z o a des z o o l o g i s c h e n Museums der k a i s e r l i c h e n Akademie der W i s s e n s c h a f t zu S t . P e t e r s b u r g . B u l l . Acad. Imp. Sc. S t . P e t e r s b u r g . 15: 271-292. von L i n s t o w , 0. F. B. 1903. H e l m i n t h o l o g i s c h e Beobachtungen. C e n t r a l b l a t t f u r B a k t e r i o l o g i e und P a r a s i t e n k u n d e 34: 526-531 . Wagener, G. R. 1952. E n t h e l m i n t h i c a I I I . Ueber e i n e n neuen i n der Chimaera monstrosa gefundenen Eigenweideworm, Amphiptyches urna Gr. et Wag. A r c h . Anat. P h y s i o l , u. W iss. M e d i c i n . 543-554. Wagener, G. R. 1858. E n t h e l m i n t h i c a . V. Ueber A m p h i l i n a f o l i a c e a m i h i (M. f o l i a c e u m Rud.), G y r o c o t y l e D i e s i n g und Amphiptyches Gr. W. A r c h . N a t u r g . 24: 244-249. [ i n 113 Braun, 1889] Ward, H. B. 1912. Some p o i n t s i n the g e n e r a l anatomy of G y r o c o t y l e . Z o o l . J a h r b . S u p p l . 15, F e s t s c h r i f t 60. G e b u r t s t a g J . W. Spengel. 717-738. Wardle, R. A. 1932. The Cestoda of Canadian F i s h e s . I . The P a c i f i c c o a s t r e g i o n . C o n t r i b . Can. B i o l . F i s h . n. s. 7: 221-243. Wardle, R. A.; McLeod, J . A. 1952. The Zoology of Tapeworms. U n i v . M i n n e s o t a P r e s s , M i n n e a p o l i s . 780 p. Watrous, L. E.; Wheeler, Q. D. 1981. The out-group comparison method of c h a r a c t e r a n a l y s i s . S y s t . Z o o l . 30: 1-11. Watson, E. E. 1911. The genus G y r o c o t y l e and i t s s i g n i f i c a n c e f o r problems of c e s t o d e s t r u c t u r e and phylogeny. U n i v . C a l i f o r n i a P u b l . Z o o l . 6: 353-468. Wedl, C. 1855. H e l m i n t h o l o g i s c h e N o t i z e n . S t z g s b e r . d. K. Akad. d. Wiss. Math. n a t . K l . Bd. XVI. Wien. p. 318. W i l e y , E. 0. 1981. P h y l o g e n e t i c s , the t h e o r y and p r a c t i c e of p h y l o g e n e t i c s y s t e m a t i c s . W i l e y - I n t e r s c i e n c e , New York. Woodland, W. N. F. 1923a. On some remarkable new forms of C a r y o p h y l l a e i d a e from the A n g l o - E g y p t i a n Sudan, and a r e v i s i o n of the f a m i l i e s of the C e s t o d a r i a . Q u a r t . J . M i c r . Sc. 67: 435-472. Woodland, W. N. F. 1923b. On A m p h i l i n a paragonopora sp. n. and a h i t h e r t o u n d e s c r i b e d phase i n the l i f e h i s t o r y of the genus. Quart. J . M i c r . Sc. 67: 478-84. Yamaguti, S. 1934. S t u d i e s on the h e l m i n t h fauna of Japan, P a r t 4. Cestodes of f i s h e s . Japan. J . Z o o l . 6: 1-112. Yamaguti, S. 1954. P a r a s i t i c worms m a i n l y from C e l e b e s , P a r t 6. Cestodes of f i s h e s . A c t a Med. Okayama 8: 353-374. Yamaguti, S. 1959. Systema Helminthum. V o l . 2, The c e s t o d e s of v e r t e b r a t e s . I n t e r s c i e n c e P u b l i s h e r s , I n c . New York. 860 p. 114 F i g u r e 1 - P h y l o g e n e t i c R e l a t i o n s h i p s of t h e Cercomeromorphae Bychowsky, 1937 Legend: (1) armed cercomer p r e s e n t ; (2) d o u b l e d c e r e b r a l nervous commissures; (3) d o u b l e d p o s t e r i o r nervous commissures; (4) p a i r e d l a t e r a l v a g i n a e p r e s e n t ; (5) b i f u r c a t e gut p r e s e n t ; (6) cercomer armed w i t h 10-16 hooks; (7) r e t i c u l a t e e x c r e t o r y system p r e s e n t ; (8) l o s s of i n t e s t i n e ; (9) p o s t e r i o r body i n v a g i n a t i o n p r e s e n t ; (10) c o p u l a t o r y s t y l e t a b s e n t ; (11) cercomer reduced i n s i z e and p a r t i a l l y or t o t a l l y i n v a g i n a t e d ; (12) male pore not p r o x i m a t e t o u t e r i n e o p e n i n g ; (13) v e s t i g i a l o r a l s t r u c t u r e s p r e s e n t ; (14) r o s e t t e p r e s e n t ; (15) cercomer armed w i t h ten e q u a l -s i z e d hooks; (16) v a g i n a and male pore p r o x i m a t e ; (17) cercomer t o t a l l y i n v a g i n a t e d ; (18) g e n i t a l p o r e s i n p o s t e r i o r h a l f of body; (19) cercomer armed w i t h hooks of two s i z e s ; (20) p o l y z o i c body; (21) complex l i f e c y c l e s ; (22) p r o t o n e p h r i d i a i n p o s t e r i o r h a l f of body;(23) cercomer l o s t i n ontogeny; (24) cercomer armed w i t h 6 e q u a l - s i z e d hooks. M o d i f i e d from B r o o k s e t a l . , 1985a. 116 F i g u r e 2 - P h y l o g e n e t i c r e l a t i o n s h i p s of the C e r c o m e r i a B r o o k s , 1982 Temnocephalidea Udonellidea Aspidocotylea Digenea Monogenea Gyrocotylidea Amphili nidea Eucestoda 118 F i g u r e 3 - Body Shapes of A m p h i l i n i d e a n s (a) e l o n g a t e body of G i g a n t o l i n a e l o n g a t a ; (b) f u s i f o r m body of S c h i z o c h o e r u s a f r i c a n u s , redrawn from Donges and Harder"^ 1966; (c) e l l i p t i c a l body of A m p h i l i n a j a p o n i c a ; (a) and (c) t r a c e d d i r e c t l y from specimens. 119 120 F i g u r e 4 - The s u r f a c e of the tegument of a m p h i l i n i d e a n s (a) i r r e g u l a r r i d g e s and d e p r e s s i o n s , drawn from G i g a n t o l i n a e l o n g a t a ; (b) c o n c e n t r i c a n n u l a t i o n s ; f r e e h a n d s k e t c h of S c h i z o c h o e r u s l i g u l o i d e u s . 121 b 122 F i g u r e 5 - T e r m i n a l G e n i t a l i a of A m p h i l i n a Diagrammatic s k e t c h of the t e r m i n a l g e n i t a l i a of A m p h i l i n a , showing v a g i n a c r o s s i n g male d u c t , w i t h p o i n t of o v e r l a p (a) d i s t a l t o e j a c u l a t o r y b u l b ; or (b) p r o x i m a l t o e j a c u l t o r y b u l b . 123 s.r. v.def. ej.b ej.d 124 F i g u r e 6 - F o r m a t i o n of the a c c e s s o r y s e m i n a l r e c e p t a c l e s Diagrammatic s k e t c h of the female g e n i t a l d u c t s of a m p h i l i n i d e a n s , showing the two t y p e s of a c c e s s o r y s e m i n a l r e c e p t a c l e s : (a) a c c e s s o r y r e c p t a c l e formed as an e x t e n s i o n of the v a g i n a ; and (b) a c c e s s o r y r e c p t a c l e formed as a d i l a t i o n of the s e m i n a l d u c t . 125 126 F i g u r e 7 - V a r i a t i o n i n o v a r y shape i n the a m p h i l i n i d e a n s . Diagrammatic s k e t c h e s of the f o u r o v a r y shapes o b s e r v e d i n a m p h i l i n i d e a n s : (a) b i l o b e d , a s y m m e t r i c a l , and c o a r s e l y l o b a t e ; (b) b i l o b e d , s y m m e t r i c a l , and f i n e l y l o b a t e ; (c) k i d n e y - s h a p e d , smooth, and e n t i r e ; and (d) s i n g l e , i r r e g u l a r and e n t i r e . 127 d 128 F i g u r e 8 - S p a t i a l r e l a t i o n s h i p s of the female g e n i t a l d u c t s of a m p h i l i n i d e a n s Diagrammatic s k e t c h e s of female g e n i t a l d u c t s , showing changes i n the s p a t i a l r e l a t i o n s of the s t r u c t u r e s . Shapes and s i z e s of s t r u c t u r e s have been kept c o n s t a n t f o r c l a r i t y ; (a) b a s i c p a t t e r n , observed i n the o u t g r o u p , and i n G i g a n t o l i n a e l o n g a t a . (b) appears t o be formed from ( a l by r o t a t i o n of the ovary under the s e m i n a l r e c e p t a c l e ; (c) appears t o be formed from (a) be bending of the v a g i n a a t a p p r o x i m a t e l y r i g h t a n g l e s ; (d) appears t o be formed from the b a s i c p a t t e r n (a) by e x t e n s i o n of the v a g i n a ; ( b ) , (c) and (d) appear t o have a r i s e n i n d e p e n d e n t l y from ( a ) . 129 130 F i g u r e 9 - A m p h i l i n a f o l i a c e a Composite, v e n t r a l v i e w , a, a p i c a l i n v a g i n a t i o n ; e j . b., e j a c u l a t o r y b u l b ; e j . d. e j a c u l a t o r y d u c t ; m, M e h l i s g l a n d ; o, o v a r y ; s . r . , s e m i n a l r e c e p t a c l e ; t , t e s t e s ; u, u t e r u s ; v, v a g i n a ; v. d e f . , vas d e f e r e n s ; v i t . , v i t e l l a r i a . 131 ej .d 132 F i g u r e 10 - Amphi1ina j a p o n i c a Composite. (a) e n t i r e specimen, v e n t r a l view; (b) ootype r e g i o n , d o r s a l v i e w ; supplemented from Goto and I s h i i ( 1936). a, a p i c a l i n v a g i n a t i o n ; e j . b., e j a c u l a t o r y b u l b ; e.j. d. e j a c u l a t o r y d u c t ; m, M e h l i s g l a n d ; o, o v a r y ; s . r . , s e m i n a l r e c e p t a c l e ; t , t e s t e s ; u, u t e r u s ; v, v a g i n a ; v. d e f . , vas d e f e r e n s ; v i t . , v i t e l l a r i a . 133 134 1 35 F i g u r e 11 - S c h i z o c h o e r u s paragonopora Composite. (a) e n t i r e specimen; (b) a n t e r i o r end, d o r s a l v i e w, showing l o c a t i o n of u t e r i n e pore and p a r t i a l e v e r s i o n of pharynx; (c) p o s t e r i o r end, v e n t r a l v i e w ; (d) t e r m i n a l g e n i t a l i a , d o r s a l v i e w ; (e) ootype r e g i o n , d o r s a l v i e w, a, a p i c a l i n v a g i n a t i o n ; a . s . r . , a c c e s s o r y s e m i n a l r e c e p t a c l e ; c . l . , c a u d a l l o b e s ; e j . b., e j a c u l a t o r y b u l b ; e j . d. e j a c u l a t o r y d u c t ; m, M e h l i s g l a n d ; o, o v a r y ; s . r . , s e m i n a l r e c e p t a c l e ; sem. d., s e m i n a l d u c t ; t , t e s t e s ; u, u t e r u s ; v, v a g i n a ; v. d e f . , vas d e f e r e n s ; v i t . , v i t e l l a r i a . 5 mm 137 200 / u m 138 139 5 m m v 140 141 F i g u r e 12 - S c h i z o c h o e r u s 1 i g u l o i d e u s Composite, v e n t r a l v i e w . (a) e n t i r e specimen; (b) a n t e r i o r end, showing l o c a t i o n of u t e r i n e p o r e ; (c) p o s t e r i o r end; (d) p o s t e r i o r end, showing e x t e n t of s e m i n a l r e c e p t a c l e ; (e) ootype r e g i o n , a, a p i c a l i n v a g i n a t i o n ; a . s . r . , a c c e s s o r y s e m i n a l r e c e p t a c l e ; e j . b., e j a c u l a t o r y b u l b ; e j . d. e j a c u l a t o r y d u c t ; m, M e h l i s g l a n d ; o, o v a r y ; s . r . , s e m i n a l r e c e p t a c l e ; sem. d., s e m i n a l d u c t ; t , t e s t e s ; u, u t e r u s ; v, v a g i n a ; v. d e f . , vas d e f e r e n s ; v i t . , v i t e l l a r i a . 142 vit t u s.r v.ef v. def ej. b o a.s.r m 144 e j . d 145 146 F i g u r e 13 - S c h i z o c h o e r u s j a n i c k i i Composite, v e n t r a l v i e w s . (a) e n t i r e specimen, i n t e r n a l s t r u c t u r e s drawn from f r e e h a n d s k e t c h e s ; drawn t o s c a l e ; (b) ootype r e g i o n , f r e e h a n d s k e t c h supplemented from Fuhrmann, 1930; not drawn t o s c a l e , a, a p i c a l i n v a g i n a t i o n ; a . s . r . , a c c e s s o r y s e m i n a l r e c e p t a c l e ; e j . b., e j a c u l a t o r y b u l b ; e j . d. e j a c u l a t o r y d u c t ; m, M e h l i s g l a n d ; o, o v a r y ; s . r . , s e m i n a l r e c e p t a c l e ; sem. d., s e m i n a l d u c t ; t , t e s t e s ; u, u t e r u s ; v, v a g i n a ; v. d e f . , vas d e f e r e n s ; v i t . , v i t e l l a r i a . 147 2 cm 148 s . r 149 F i g u r e 14 - S c h i z o c h o e r u s a f r i c a n u s V e n t r a l v i e w , redrawn from Donges and H a r d e r , 1966. a, a p i c a l i n v a g i n a t i o n ; a . s . r . , a c c e s s o r y s e m i n a l r e c e p t a c l e ; e j . b., e j a c u l a t o r y b u l b ; e j . d. e j a c u l a t o r y d u c t ; m, M e h l i s g l a n d ; o, o v a r y ; s . r . , s e m i n a l r e c e p t a c l e ; sem. d., s e m i n a l d u c t ; t , t e s t e s ; u, u t e r u s ; v, v a g i n a ; v. d e f . , vas d e f e r e n s ; v i t . , v i t e l l a r i a . 150 5mm 151 F i g u r e 15 - G i g a n t o l i n a e l o n g a t a Composite. (a) e n t i r e specimen, d o r s a l v i e w ; (b) p o s t e r i o r end of body, d o r s a l v i e w ; (c) ootype r e g i o n , v e n t r a l v i e w , a, a p i c a l i n v a g i n a t i o n ; a . s . r . , a c c e s s o r y s e m i n a l r e c e p t a c l e ; e j . b., e j a c u l a t o r y b u l b ; e j . d. e j a c u l a t o r y d u c t ; m, M e h l i s g l a n d ; o, o v a r y ; s . r . , s e m i n a l r e c e p t a c l e ; sem. d., s e m i n a l d u c t ; t , t e s t e s ; u, u t e r u s ; v, v a g i n a ; v. d e f . , vas d e f e r e n s ; v i t . , v i t e l l a r i a . 152 153 154 155 F i g u r e 16 - G i g a n t o l i n a magna V e n t r a l v i e w . (a) p o s t e r i o r end; supplemented from Yamaguti (1954); (b) a n t e r i o r end; (c) ootype r e g i o n , a, a p i c a l i n v a g i n a t i o n ; a . s . r . , a c c e s s o r y s e m i n a l r e c e p t a c l e ; e j . b., e j a c u l a t o r y b u l b ; e j . d. e j a c u l a t o r y d u c t ; m, M e h l i s g l a n d ; o, o v a r y ; s . r . , s e m i n a l r e c e p t a c l e ; sem. d., s e m i n a l d u c t ; t , t e s t e s ; u, u t e r u s ; v, v a g i n a ; v. d e f . , vas d e f e r e n s ; v i t . , v i t e l l a r i a . 156 5 mm 157 158 500 yum 159 F i g u r e 17 - H y p o t h e s i s of p h y l o g e n e t i c r e l a t i o n s h i p f o r the A m p h i l i n i d e a Legend: (1) two t y p e s of cercomer hooks p r e s e n t ; (2) male pore l o c a t e d a t p o s t e r i o r end; (3) v a g i n a l pore l o c a t e d a t p o s t e r i o r end: (4) tegument w i t h i r r e g u l a r r i d g e s and d e p r e s s i o n s ; (5) u t e r u s N-shaped; (6) body e l l i p t i c a l (7) t e s t e s p a r t i a l l y s c a t t e r e d ; (8) v a g i n a c r o s s i n g male duct p r o x i m a l t o e j a c u l a t o r y b u l b ; (9) s u p e r c o i l i n g of t h i r d u t e r i n e l i m b p r e s e n t ; ( 1 0 ) ovary r o t a t e d under s e m i n a l r e c e p t a c l e ; (11) t e s t e s s c a t t e r e d ; (12) v a g i n a c r o s s i n g male duct d i s t a l t o e j a c u l a t o r y b u l b ; (13) p o s t e r i o r end w i t h s m a l l p a p i l l a i n d e p r e s s i o n ; (14) s e m i n a l r e c e p t a c l e l a r g e ; (15,16) ovary kidney-shaped, e n t i r e and smooth; (17) vas d e f e r e n s not c o i l e d ; (18) u t e r u s l o o p e d ; (19) U t e r u s d i l a t e d ; (20) p o s t e r i o r end w i t h l a r g e p a p i l l a i n d e p r e s s i o n ; (21) v a g i n a l pore m u s c u l a r ; (22) ovary b i l o b e d , s y m m e t r i c a l , f i n e l y l o b a t e ; (23) ovary r o t a t e d under s e m i n a l r e c e p t a c l e ; (24) v a g i n a l e x t e n s i o n p r e s e n t ; (25) ductus y a m a g u t i i p r e s e n t ; (26) common g e n i t a l pore p r e s e n t ; (27) d i l a t i o n of s e m i n a l d u c t p r e s e n t ; (28) Pharynx s t r o n g l y m u s c u l a r ; (29) t e s t e s p a i r e d ; (30) v a g i n a c o i l e d ; (31) d i l a t i o n of s e m i n a l duct p r e s e n t ; (31) u t e r i n e pore opening a t a n t e r i o r end of a p i c a l i n v a g i n a t i o n ; (32) u t e r i n e s i z e r e d u c e d ; (33) a c c e s s o r y s e m i n a l r e c e p t a c l e formed as d i l a t i o n of s e m i n a l duct p r e s e n t ; (34) c a u d a l l o b e s p r e s e n t ; (35) s i z e of s e m i n a l r e c e p t a c l e r e d u c e d ; (36) o v a r y s i n g l e , i r r e g u l a r ; (37) v a g i n a bent; (38) tegument w i t h c o n c e n t r i c a n n u l a t i o n s ; (39) v a g i n a d o u b l e ; (40) v a g i n a e l o n g a t e d ; (41) u t e r i n e duct a t r o p h i e d ; (42) d e s c e n d i n g l i m b of N-shaped u t e r u s a d j a c e n t t o t e r m i n a l l i m b ; (43) v i t e l l a r i a p o o r l y d e v e l o p e d ; (44) v a g i n a l e x t e n s i o n p r e s e n t ; (45) body f u s i f o r m ; (46) t e s t e s u n p a i r e d , i n wide bands. 160 A m p h i I ina f o l i a c e a A m p h i l ina j a p o n i c a t ^ - i - t r i G i g a n t o l i na m a g n a G i g a n t o l i n a e l o n g a t a S c h i z o c h o e r u s p a r a g o n o p o r a S c h i z o c h o e r u s l i g u l o i d e u s S c h i z o c h o e r u s j a n i c k i i S c h i z o c h o e r u s af r i c a n u s 161 F i g u r e 18 - H o s t s of A m p h i l i n i d e a n s H y p o t h e s i s of p h y l o g e n e t i c r e l a t i o n s h i p f o r the a m p h i l i n i d e a n s , w i t h h o s t names s u s t i t u t e d f o r names of p a r a s i t e t a x a . Acipenser iformes Perc i fo rmes Chelonia S i l u r i f o r m e s O s t e o g l o s s i fo rmes Mormyr i f o r m e s 163 F i g u r e 19 - P h y l o g e n e t i c r e l a t i o n s h i p s of h o s t s of a m p h i l i n i d e a n s P h y l o g e n e t i c r e l a t i o n s h i p s of the t e l e o s t e a n h o s t s of a m p h i l i n i d e a n s , based on (a) the p a r a s i t e c l a d ogram, and (b) the p h y l g e n e t i c a n a l y s i s of Lauder and Liem, 1982. Acipenser i formes 165 F i g u r e 20 - P h y l o g e n e t i c r e l a t i o n s h i p s of a m p h i l i n i d e a n s , showing p o s t u l a t e d c o l o n i z a t i o n s . Euras ia N. A m e r i c a Indian Ocean A u s t r a l i a India S . A m e r i c a A f r i c a 167 F i g u r e 21 - The b i o g e o g r a p h i c d i s t r i b u t i o n of a m p h i l i n i d e a n p l a t y h e l m i n t h s . A c i p e n s e r i fo rmes Perc i fo rmes Chelonia S i l u r i f o r m e s O s t e o g l o s s i f o r m e s Mormyr i f o r m e s 169 F i g u r e 22 - Comparison of the p h y l o g e n e t i c r e l a t i o n s h i p s of a m p h i l i n i d e a n s w i t h hypotheses of area r e l a t i o n s h i p (a) Area cladogram based on f o s s i l t e t r a p o d s ( C o l b e r t , 1981), e x t a n t t e t r a p o d s ( C r a c r a f t , 1972) and e x t a n t f r e s h w a t e r t e l e o s t s ( G o s l i n e , 1972); (b) f i t of the c l a d o g r a m p r e s e n t e d i n (a) t o t h e p a r a s i t e t r e e ; Aust ra l ia India S. A m e r i c a A f r i c a A u s t r a l i a India S Amer ica A f r i c a 171 (c) a r e a cladogram based on B r u s c a (1984) and Thomson (1981); (d) f i t of (c) t o the p a r a s i t e t r e e ; 173 (e) a r e a cladogram based on Rosen (1978); ( f ) f i t of (e) t o the p a r a s i t e t r e e ; Austral ia India S. Amer ica A f r i c a India A u s t r a l i a on A f r i c a S. A m e r i c a 176 (g) a r e a cladogram based on D i e t z and Holden (1971); (h) f i t of (g) t o the p a r a s i t e t r e e . 177 F i g u r e 23 - The f u n n e l of g y r o c o t y l i d s Median s a g g i t a l cut-away view of G y r o c o t y l e u r n a , showing the d o r s a l p o r e . Redrawn from Fuhrmann, 1931 178 179 F i g u r e 24 - The g e n i t a l n o t c h of g y r o c o t y l i d s . Diagrammatic s k e t c h e s of the a n t e r i o r end, showing ( a pronounced g e n i t a l n o t c h w i t h matching n o t c h ; (b) s m a l l g e n i t a l n o t c h w i t h o u t a matching n o t c h ; and (c the absence of the g e n i t a l n o t c h . 180 (0 181 F i g u r e 25 - The t e s t e s and u t e r i n e sac Diagrammatic s k e t c h e s of the a n t e r i o r end, showing (a) the t e s t e s e x t e n d i n g beyond the s m a l l u t e r i n e s a c ; (b) the t e s t e s e x t e n d i n g t o the p o s t e r i o r margin of the medium-sized u t e r i n e s a c ; (c) the t e s t e s not e x t e n d i n g as f a r as the p o s t e r i o r margin o.of the medium-sized u t e r i n e s a c ; and (d) the t e s t e s e x t e n d i n g t o the p o s t e r i o r margin of the l a r g e r u t e r i n e s a c . 182 183 F i g u r e 26 - Tegumental s p i n e s of g y r o c o t y l i d s . (a) p h a r y n g e a l s p i n e s , r u g o s a ; (b) body s p i n e s , G. conf usa; (c) p h a r y n g e a l s p i n e , G_^  conf usa; (d) p h a r y n g e a l and body s p i n e s , G^ p a r v i s p i n o s a forma p a r v i s p i n o s a ; (e) p h a r y n g e a l s p i n e s , G^ p a r v i s p i n o s a forma m a g n i s p i n o s a ; ( f ) body s p i n e s , G^ p a r v i s p i n o s a forma m a g n i s p i n o s a ; (g) p h a r y n g e a l s p i n e s , G_^  maxima; (h) body s p i n e s , G. maxima-r ( j ) p h a r y n g e a l and body s p i n e s , G^ a b y s s T c o l a ; (k) p h a r y n g e a l and body s p i n e s , G_^  urna; (p) body s p i n e s , G. urna; (q) p h a r y n g e a l s p i n e s , G^ f i m b r i a t a ; (77 body s p i n e s , G. f i m b r i a t a . s p i n e s , major; (m) (n) p h a r y n g e a l s p i n e s , a. 50/jm b. c. 185 f. 186 1 0 0 jjm 1 0 0 yum 188 n . 50/um 50 pm 50/jm 50 jum 191 F i g u r e 27 - G y r o c o t y l e rugosa Composite, v e n t r a l v i e w s . (a) e n t i r e specimen; (b) t e r m i n a l g e n i t a l i a , a, a p i c a l i n v a g i n a t i o n ; m, male p o r e ; o, o v a r y ; s, t e g u m e n t a l s p i n e s ; s . r . , s e m i n a l r e c e p t a c l e ; t , t e s t e s ; u, u t e r u s ; v, v a g i n a . 192 193 194 F i g u r e 28 - U t e r i n e c o n f o r m a t i o n of G y r o c o t y l e rugosa Diagrammatic s k e t c h e s of the u t e r i n e c o n f o r m a t i o n of G y r o c o t y l e rugosa (a) as d e p i c t e d by L i n t o n (1924); as d e p i c t e d by Manter, 1951; and (c) as i t appears i n the specimens i l l u s t r a t e d i n f i g . 27. 195 Numbering e r r o r . Text f o r page 195 not a v a i l a b l e . 196 c 197 F i g u r e 29 - D i s t r i b u t i o n of v i t e l l a r i a i n G y r o c o t y l e rugosa The d i s t r i b u t i o n of the v i t e l l a r i a i s f a i r l y c o n s t a n t i n g y r o c o t y l i d s , u s u a l l y e x t e n d i n g from the m i d d l e of the a p i c a l i n v a g i n a t i o n t o the l e v e l of the d o r s a l p o r e . The d i s t a n c e s between the f o l l i c l e s appear t o be age-dependent, o l d e r , l a r g e r specimens h a v i n g more d i f f u s e v i t e l l a r i a . 198 5 m m 199 F i g u r e 30 - G y r o c o t y l e n y b e l i n i Composite, v e n t r a l v i e w , supplemented from Joyeux and Baer, 1950, 1951, 1961. S c a l e a p p r o x i m a t e . (a) e n t i r e specimen; (b) r o s e t t e . a, a p i c a l i n v a g i n a t i o n ; m, male pore; o, o v a r y ; r , r o s e t t e ; s . r . , s e m i n a l r e c e p t a c l e ; t , t e s t e s ; u, u t e r u s ; v, v a g i n a . 200 201 202 F i g u r e 31 - G y r o c o t y l e maxima V e n t r a l v i e w, a, a p i c a l i n v a g i n a t i o n ; m, male pore; o, o v a r y ; r , r o s e t t e ; s, t e g u m e n t a l s p i n e s ; s . r . , s e m i n a l r e c e p t a c l e ; t , t e s t e s ; u, u t e r u s ; v, v a g i n a . S i z e of s p i n e s e x a g g e r a t e d . 203 f 204 F i g u r e 32 - G y r o c o t y l e p a r v i s p i n o s a Both forms of G y r o c o t y l e p a r v i s p i n o s a d e s c r i b e d by Lynch (1945) a r e i l l u s t r a t e d ; d r a wings of e n t i r e specimens a r e v e n t r a l v i e w s . (a) G y r o c o t y l e  p a r v i s p i n o s a forma p a r v i s p i n o s a ; (b) G y r o c o t y l e  p a r v i s p i n o s a forma m a g n i s p i n o s a ; (c) ootype r e g i o n , d o r s a l view. a, a p i c a l i n v a g i n a t i o n ; m, male p o r e ; o, o v a r y ; r , r o s e t t e ; s, tegumental s p i n e s ; s . r . , s e m i n a l r e c e p t a c l e ; t , t e s t e s ; u, u t e r u s ; v, v a g i n a . 2 0 5 206 207 208 F i g u r e 33 - G y r o c o t y l e c o n f u s a a, a p i c a l i n v a g i n a t i o n ; m, male p o r e ; o, o v a r y ; r , r o s e t t e ; s, tegumental s p i n e s ; s . r . , s e m i n a l r e c e p t a c l e ; t , t e s t e s ; u, u t e r u s ; v, v a g i n a . Redrawn from van der Land and Dienske (1968). 209 F i g u r e 34 - G y r o c o t y l e a b y s s i c o l a a, a p i c a l i n v a g i n a t i o n ; m, male p o r e ; o, o v a r y ; r o s e t t e ; s, tegumental s p i n e s ; s . r . , s e m i n a l r e c e p t a c l e ; t , t e s t e s ; u, u t e r u s ; v, v a g i n a . Semidiagrammatic; redrawn from van der Land and Templeman, 1968. 211 212 F i g u r e 35 - G y r o c o t y l e n i g r o s e t o s a a, a p i c a l i n v a g i n a t i o n ; m, male p o r e ; o, o v a r y ; r , r o s e t t e ; s, tegumental s p i n e s ; s . r . , s e m i n a l r e c e p t a c l e ; t , t e s t e s ; u, u t e r u s ; v, v a g i n a . 213 214 F i g u r e 36 - G y r o c o t y l e urna a, a p i c a l i n v a g i n a t i o n ; m, male p o r e ; o, o v a r y ; r , r o s e t t e ; s, tegumental s p i n e s ; s . r . , s e m i n a l r e c e p t a c l e ; t , t e s t e s ; u, u t e r u s ; v, v a g i n a . 215 216 F i g u r e 37 - G y r o c o t y l e major a, a p i c a l i n v a g i n a t i o n ; m, male pore; o, o v a r y ; r , r o s e t t e ; s, t e g u m e n t a l s p i n e s ; s . r . , s e m i n a l r e c e p t a c l e ; t , t e s t e s ; u, u t e r u s ; v, v a g i n a . Semidiagrammatic; redrawn from van der Land and Templeman, 1968. 217 218 F i g u r e 38 - G y r o c o t y l e f i m b r i a t a Composite; v e n t r a l v i e w , a, a p i c a l i n v a g i n a t i o n ; m, male p o r e ; o, o v a r y ; r , r o s e t t e ; s, tegumental s p i n e s ; s . r . , s e m i n a l r e c e p t a c l e ; t , t e s t e s ; u, u t e r u s ; v, v a g i n a . 219 220 F i g u r e 39 - Hypotheses of R e l a t i o n s h i p f o r the G y r o c o t y l i d e a (a) l e g e n d : (1) t e n cercomer hooks of e q u a l s i z e p r e s e n t ; (2,3) s h o r t narrow f u n n e l p r e s e n t ; (4) s m a l l g e n i t a l n o t c h p r e s e n t ; (5) body margins c r e n u l a t e ; (6) s m a l l s p i n e s p r e s e n t over most of the body s u r f a c e , l a r g e s p i n e s p r e s e n t around pharynx; (7) s p i n e s l o n g and s l e n d e r ; (8) complex f o l d i n g of u t e r u s p r e s e n t ; (9) s p i n e s s h o r t and t h i c k ; (10) margins c r e n a t e , w i t h a r e l a t i v e l y s m a l l number of p l i c a t i o n s ; (11) l a r g e t e g u m e n t a l s p i n e s p r e s e n t on much of body s u r f a c e ; (12) u t e r i n e sac l a r g e ; (13,14) t e s t e s e x t e n d i n g t o the p o s t e r i o r margin of the u t e r i n e s a c ; (15) t e s t e s e x t e n d i n g o n l y t o the a n t e r i o r margin of the u t e r i n e s a c ; (16) c o p u l a t o r y p a p i l l a a b s e n t ; (17) f u n n e l e l o n g a t e ; (18) u t e r i n e sac e n l a r g e d ; (19) t e g u m e n t a l s p i n e s a b s e n t ; (20) body margins c r e n u l a t e ; (21) g e n i t a l n o t c h a b s e n t ; (22) t e s t e s e x t e n d i n g t o the p o s t e i o r margin of an e n l a r g e d u t e r i n e s a c ; (23) g e n i t a l n o t c h pronounced; (24) s p i n e s s h o r t and t h i c k ; (25) f u n n e l s h o r t and wide; (26) l a t e r a l margins c r e n a t e , w i t h many e l a b o r a t e p l i c a t i o n s ; (27) s p i n e s absent from body m a r g i n s ; (28) c o p u l a t o r y p a p i l l a a b s e n t . 221 222 223 (b) l e g e n d : ( l ) t e n cercomer hooks of e q u a l s i z e p r e s e n t ; (2,3) s h o r t narrow f u n n e l p r e s e n t ; (4) s m a l l g e n i t a l n o t c h p r e s e n t ; (5) body margins c r e n u l a t e ; (6) s m a l l s p i n e s p r e s e n t over most of the body s u r f a c e , l a r g e s p i n e s p r e s e n t around pharynx; (7) s p i n e s l o n g and s l e n d e r ; (8) complex f o l d i n g of u t e r u s p r e s e n t ; (9) s p i n e s s h o r t and t h i c k ; (10) margins c r e n a t e , w i t h a r e l a t i v e l y s m a l l number of p l i c a t i o n s ; (11) l a r g e tegumental s p i n e s p r e s e n t on much of body s u r f a c e ; (12) u t e r i n e sac l a r g e ; (13,14) t e s t e s e x t e n d i n g t o the p o s t e r i o r margin of the u t e r i n e sac; (15) t e s t e s e x t e n d i n g o n l y t o the a n t e r i o r margin of the u t e r i n e s a c ; (16) c o p u l a t o r y p a p i l l a a b s e n t ; (17) f u n n e l e l o n g a t e ; (18) u t e r i n e sac e n l a r g e d ; (19) t e g u m e n t a l s p i n e s a b s e n t ; (20) body margins c r e n u l a t e ; (21) g e n i t a l n o t c h a b s e n t ; (22) t e s t e s e x t e n d i n g t o the p o s t e r i o r margin of an e n l a r g e d u t e r i n e s a c ; (23) g e n i t a l n o t c h pronounced; (24) s p i n e s s h o r t and t h i c k ; (25) f u n n e l s h o r t and wide; (26) l a t e r a l margins c r e n a t e , w i t h many e l a b o r a t e p l i c a t i o n s ; (27) s p i n e s absent from body margins; (28) c o p u l a t o r y p a p i l l a a b s e n t . 224 225 F i g u r e 40 - Consensus t r e e f o r the G y r o c o t y l i d e a (1) t e n cercomer hooks of e q u a l s i z e p r e s e n t ; (2,3) s h o r t narrow f u n n e l p r e s e n t ; (4) s m a l l g e n i t a l n o t c h p r e s e n t ; (5) body margins c r e n u l a t e ; (6) s m a l l s p i n e s p r e s e n t over most of the body s u r f a c e , l a r g e s p i n e s p r e s e n t around pharynx; (7) s p i n e s l o n g and s l e n d e r ; (8) complex f o l d i n g of u t e r u s p r e s e n t ; (9) s p i n e s s h o r t and t h i c k ; (10) margins c r e n a t e , w i t h a r e l a t i v e l y s m a l l number of p l i c a t i o n s ; (11) l a r g e t e g u m e n t a l s p i n e s p r e s e n t on much of body s u r f a c e ; (12) u t e r i n e sac l a r g e ; (13,14) t e s t e s e x t e n d i n g t o the p o s t e r i o r margin of the u t e r i n e s a c ; (15) t e s t e s e x t e n d i n g o n l y t o the a n t e r i o r margin of the u t e r i n e s a c ; (16) c o p u l a t o r y p a p i l l a a b s e n t ; (17) f u n n e l e l o n g a t e ; (18) u t e r i n e sac e n l a r g e d ; (19) tegumental s p i n e s a b s e n t ; (20) body margins c r e n u l a t e ; (21) g e n i t a l n o t c h a b s e n t ; (22) t e s t e s e x t e n d i n g t o the p o s t e i o r margin of an e n l a r g e d u t e r i n e s a c ; (23) g e n i t a l n o t c h pronounced; (24) s p i n e s s h o r t and t h i c k ; (25) f u n n e l s h o r t and wide; (26) l a t e r a l margins c r e n a t e , w i t h many e l a b o r a t e p l i c a t i o n s ; (27) s p i n e s absent from body m a r g i n s ; (28) c o p u l a t o r y p a p i l l a a b s e n t . 226 227 F i g u r e 41 - The p h y l o g e n e t i c r e l a t i o n s h i p s of g y r o c o t y l i d e a n s , w i t h the b e s t - f i t t i n g host t r a n s f o r m a t i o n s e r i e s mapped on. Legend: (A) C a l l o r h i n c h u s c a l l o r h y n c h u s ; (B) Chimaera  monstrosa ; (C) C a l l o r h i n c h u s C a l l o r h i n c h u s ; H y d r o l a g u s c o l l i e i ; H y d r o l a g u s o g i l b y i ; C E ) H y d r o l a g u s a f f i n i s ; (F) Chimaera phantasma. 2 2 8 GO' 0<V ^ J2 G* o 229 F i g u r e 42 - Comparison of the p h y l o g e n e t i c r e l a t i o n s h i p s of g y r o c o t y l i d e a n s w i t h a h o s t phylogeny based on the b e s t - f i t t i n g t r a n s f o r m a t i o n s e r i e s . 230 2 3 1 F i g u r e 43 - Comparison of the p h y l o g e n e t i c r e l a t i o n s h i p s of g y r o c o t y l i d e a n s w i t h a host phylogeny based on B i g e l o w and S c h r o e d e r , 1953. 232 233 F i g u r e 44 - A r e a cladogram showing the g e o g r a p h i c d i s t r i b u t i o n of g y r o c o t y l i d e a n s . 234 235 F i g u r e 45 - H y p o t h e s i s of p h y l o g e n e t i c r e l a t i o n s h i p f o r the g y r o c o t y l i d s , showing the b e s t f i t t i n g a r e a t r a n s f o r m a t i o n s e r i e s . 236 237 F i g u r e 46 - H y p o t h e s i s of p h y l o g e n e t i c r e l a t i o n s h i p f o r the g y r o c o t y l i d s , showing the f i t an area cladogram based on the b e s t - f i t t i n g t r a n s f o r m a t i o n s e r i e s . 238 239 F i g u r e 47 - H y p o t h e s i s of p h y l o g e n e t i c r e l a t i o n s h i p f o r the c e r c o m e r i a n s , showing a d d i t i o n a l c h a r a c t e r i s t i c s i d e n t i f i e d i n the p h y l o g e n e t i c a n a l y s e s of t h e a m p h i l i n i d e a n s and g y r o c o t y l i d e a n s . Legend: (1) l a t e r a l t e s t i c u l a r bands (2) o v a r y shape; (3) e l o n g a t e f l a t t e n e d body; (4) l a r g e body s i z e ; (5) p r e s e n c e of a s i n u o u s u t e r u s ; (6) arrangement of v i t e l l a r i a , t e s t e s , and u t e r u s ; (7) s h o r t narrow f u n n e l p r e s e n t ; (8) g e n i t a l n o t c h p r e s e n t ; (8) l a t e r a l m a r g i n s c r e n u l a t e ; (10) s m a l l tegumental s p i n e s p r e s e n t on most of the body s u r f a c e , l a r g e r s p i n e s p r e s e n t around pharynx; (11) tegumental s p i n e s s m a l l and s l e n d e r ; (12) arrangement of female g e n i t a l d u c t s ; (13) tegumental o r n a m e n t a t i o n p r e s e n t ; (14) u t e r u s N-shaped. 240 241 APPENDIX A -Tab l e I - A m p h i l i n i d c h a r a c t e r m a t r i x A m p h i l i n a f o l i a c e a  A m p h i l i n a j a p o n i c a  G i g a n t o l i n a e l o n g a t a  G i g a n t o l i n a magna  S c h i z o c h o e r u s a f r i c a n u s  S c h i z o c h o e r u s j a n i c k i i  S c h i z o c h o e r u s l i g u l o i d e u s  S c h i z o c h o e r u s paragonopora a n c e s t o r 1111010002001000000000010100010000 1111010001002000000000010100010000 1110010100010100010111000209000010 1110010200010001011012010209000110 1110121100100010110111100111101001 1110121100000010110111100111101001 1110021100100010111111100111101001 1110011110100000100121001110100000 0000000000000000000000000009900000 T a b l e I I - T e l e o s t e a n r e l a t i o n s h i p s based on Lauder and Liem, 1982 ACIPENSERIFORMES 1000001 OSTEOGLOSSI FORMES 0100011 SILURIFORMES 0010111 PERCIFORMES 0001111 2 4 2 T a b l e I I I - Area m a t r i x based on C o l b e r t (1981), C r a c r a f t (1972) and G o s l i n e (1972). AUSTRALIA 1000001 INDIA 0100011 SOUTH AMERICA 0010111 AFRICA 0001111 T a b l e IV - Area cladogram based on Brusca (1984) and Thomson (1981) AUSTRALIA • 1000011 INDIA 0100011 SOUTH AMERICA 0100011 AFRICA 0001101 T a b l e V - Area cladogram based on Rosen (1978) INDIA 1000011 AFRICA 0100011 SOUTH AMERICA 0010101 AUSTRALIA 0001101 243 T a b l e VI - Area cladogram based on D i e t z and Holden (1971) INDIA 1000001 AUSTRALIA 0100011 AFRICA 0010111 SOUTH AMERICA 0001111 244 APPENDIX B -T a b l e V I I - G y r o c o t y l i d c h a r a c t e r m a t r i x G y r o c o t y l e a b y s s i c o l a 1 1 1 0221110020 G y r o c o t y l e c o n f u s a 1 1 1 0210009020 G y r o c o t y l e f i m b r i a t a 1 120321 1 1 1031 G y r o c o t y l e major 1 120321110031 G y r o c o t y l e maxima 1110221110021 G y r o c o t y l e n i g r o s e t o s a 1120321119031 G y r o c o t y l e n y b e l i n i 1210102210199 G y r o c o t y l e p a r v i s p i n o s a 1110211121020 G y r o c o t y l e rugosa 1111110000011 G y r o c o t y l e urna 1120321111031 a n c e s t o r 0000000000009 T a b l e V I I I - M a t r i x d e s c r i b i n g h o s t r e l a t i o n s h i p s as d e r i v e d from p a r a s i t e t r e e C a l l o r h i n c h u s c a l l o r h y n c h u s 1000000001 Chimaera monstrosa 0100000111 H y d r o l a g u s c o l l i e i 0010000111 H y d r o l a g u s a f f i n i s 0001001011 H y d r o l a g u s o g i l b y i 000010101 1 Chimaera phantasma 0000011011 245 MATRIX DESCRIBING HOST RELATIONSHIPS AS DERIVED FROM  BIGELOW AND SCHROEDER, 1953 C a l l o r h i n c h u s c a l l o r h y n c h u s 10000000001 Chimaera monstrosa  Chimaera phantasma  H y d r o l a g u s c o l l i e i  H y d r o l a g u s a f f i n i s  H y d r o l a g u s o g i l b y i 0100000011 1 001000001 1 1 00010001011 0000100101 1 0000010101 1 MATRIX DESCRIBING AREA RELATIONSHIPS FOR GYROCOTYLIDS Southe r n hemisphere, A t l a n t i c and P a c i f i c 100000001 N o r t h e a s t e r n A t l a n t i c 010001011 N o r t h P a c i f i c 001001011 N o r t h w e s t e r n A t l a n t i c 000100111 South P a c i f i c 000010111 

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