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UBC Theses and Dissertations

Phylogenetic analysis of the North American species of Telorchis luehe, 1899 (Cercomeria:Digenea:Telorchiidae) Macdonald, Cheryl Ann 1986

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PHYLOGENETIC ANALYSIS OF THE NORTH AMERICAN SPECIES OF TELORCHIS LUEHE, 1899 (CERCOMERIA:DIGENEA:TELORCHIIDAE) by CHERYL A. MACDONALD B . S c , U n i v e r s i t y Of B r i t i s h Columbia, 1982 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF . MASTER OF SCIENCE i n THE FACULTY OF GRADUATE STUDIES' Zoology Department We a c c e p t t h i s t h e s i s as c o n f o r m i n g t o the r e q u i r e d s t a n d a r d THE UNIVERSITY OF BRITISH COLUMBIA October 1986 © C h e r y l A. Macdonald, 1986 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 h i s 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 Zoology  The University of B r i t i s h Columbia 1956 Main Mall Vancouver, Canada V6T 1Y3 Date October 7th. 1986 DE-6 f3/81") i i A b s t r a c t T e l o r c h i i d s a r e p l a g i o r c h i f o r m i n t e s t i n a l p a r a s i t e s i n h a b i t i n g t u r t l e s , and o c c a s i o n a l l y snakes and salamanders. P r e v i o u s taxonomic r e v i s i o n s of the group have been p r o b l e m a t i c a l due t o a l a c k of i n f o r m a t i o n on i n t r a s p e c i f i c m o r p h o l o g i c a l v a r i a t i o n . In the p r e s e n t s t u d y , t e n of the t h i r t y d e s c r i b e d N o r t h American s p e c i e s are c o n s i d e r e d v a l i d . P h y l o g e n e t i c a n a l y s i s of 22 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 20 homologous s e r i e s r e s u l t s i n 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 of 95%. Only one of the c h a r a c t e r s used i n the a n a l y s i s i s h o moplasious. In o r d e r t o m a i n t a i n a c l a s s i f i c a t i o n t h a t r e f l e c t s the phylogeny of the group, o n l y one of f o u r proposed genera i s r e c o g n i z e d . A b i o g e o g r a p h i c a l a n a l y s i s i s not f e a s i b l e due t o i n c o m p l e t e c o l l e c t i n g r e c o r d s . The two most r e l a t i v e l y p l e s i o m o r p h i c t e l o r c h i i d s p e c i e s a r e found i n salamanders. F i v e of t h e e i g h t s p e c i e s from amniotes a r e c o n s i d e r e d t o have c o - s p e c i a t e d w i t h t h e i r h o s t s . One of the s e c o n d a r i l y e v o l v e d s p e c i e s i s p o s t u l a t e d t o have e v o l v e d v i a a h o s t - s w i t c h from t u r t l e s t o snakes. The o t h e r two s e c o n d a r i l y e v o l v e d s p e c i e s appear t o have a r i s e n v i a s y m p a t r i c s p e c i a t i o n , f a c i l i t a t e d by m e c h a n i c a l p r e - m a t i n g i s o l a t i o n due t o a d i f f e r e n c e i n g e n i t a l pore p o s i t i o n . As p r i m a r i l y c o e v o l v e d t e l o r c h i i d s become more h i g h l y d e r i v e d t h e r e i s an i n c r e a s e i n h o s t s p e c i f i c i t y , which i s c o n s i s t e n t w i t h the t r a d i t i o n a l view of h o s t - p a r a s i t e r e l a t i o n s h i p s . i i i T a b l e of C o n t e n t s A b s t r a c t i i L i s t of T a b l e s i v L i s t of F i g u r e s v Acknowledgement v i i INTRODUCTION 1 MATERIALS AND METHODS 5 CHARACTER ANALYSIS 6 . CHARACTERS NOT INCLUDED IN THE ANALYSIS 11 RESULTS 14 TAXONOMIC REVISION 14 SPECIES INQUIRENDA 31 KEY TO THE SPECIES OF TELORCHIS 32 PHYLOGENETIC ANALYSIS 33 DISCUSSION 34 CLASSIFICATION 34 EVOLUTIONARY HISTORY 35 A. BIOGEOGRAPHY 35 B. HOST-PARASITE RELATIONSHIPS 36 C. FUNCTIONAL/STRUCTURAL ATTRIBUTES 40 CONCLUSIONS 42 REFERENCES CITED 44 APPENDIX A 49 i v L i s t of T a b l e s I . C h a r a c t e r d a t a f o r T e l o r c h i s s p e c i e s 49 I I . Ranges of s u c k e r t o pharynx r a t i o f o r T e l o r c h i s s p e c i e s 50 V L i s t of F i g u r e s 1. Body shapes of t e l o r c h i i d s 51 2. M u s c u l a r i t y of c i r r u s sac 52 3. P o s i t i o n of c i r r u s sac 53 4. P o s i t i o n of g e n i t a l pore 54 5. U t e r i n e c o n f i g u r a t i o n 55 6. S t r u c t u r e of v i t e l l i n e f o l l i c l e s 56 7. T e l o r c h i s s i r e n i s , v e n t r a l view 57 8. T e l o r c h i s s t u n k a r d i , v e n t r a l view 57 9. T e l o r c h i s c o r t i , v e n t r a l view ,...58 10. T e l o r c h i s a u r i d i s t o m i , v e n t r a l view 58 11. T e l o r c h i s a n g u s t u s , v e n t r a l view 58 12. T e l o r c h i s s c a b r a e , v e n t r a l view 59 13. T e l o r c h i s c h e l o p i , v e n t r a l view 59 14. T e l o r c h i s r o b u s t u s , v e n t r a l view 59 15. T e l o r c h i s s i n g u l a r i s , v e n t r a l view 60 16. T e l o r c h i s a t t e n u a t u s , v e n t r a l view 60 17. T e l o r c h i s compactus, v e n t r a l view 61 18. P h y l o g e n e t i c t r e e of N o r t h American T e l o r c h i s 62 19. Map of c o n f i r m e d l o c a l i t i e s f o r T e l o r c h i s c o r t i 63 20. Map of r e p o r t e d l o c a l i t i e s f o r T e l o r c h i s c o r t i 64 21. P a r t i a l p h y l o g e n e t i c t r e e of t u r t l e t a x a 65 22. H y p o t h e s i s of h o s t - p a r a s i t e c o e v o l u t i o n 66 23. P a r t i a l p h y l o g e n e t i c t r e e of ho s t t a x a w i t h s e c o n d a r i l y e v o l v e d p a r a s i t e s p e c i e s mapped on 67 24. P h y l o g e n e t i c t r e e of T e l o r c h i s s p e c i e s i n amniotes ...68 V I 25. P o s s i b l e c o m b i n a t i o n s of hos t range and s p e c i f i c i t y ..69 26. Host s p e c i f i c i t y of T e l o r c h i s s p e c i e s i n amniotes ....70 27. Summary cladogram of the h y p o t h e s i z e d e v o l u t i o n a r y h i s t o r y of the N o r t h American s p e c i e s of T e l o r c h i s ...71 v i i Acknowledgement I would l i k e t o thank Dr. J . R a l p h L i c h t e n f e l s and Pat P i l i t t (U.S. N a t i o n a l Museum, B e l t s v i l l e ) and Mary H. P r i t c h a r d (H. W. Manter L a b o r a t o r y , U n i v e r s i t y of Nebraska) f o r t h e i r generous l o a n s of specimens. I would a l s o l i k e t o thank Pat Shaw f o r h i s a s s i s t a n c e i n p r e p a r i n g the f i g u r e s . I would e s p e c i a l l y l i k e t o thank Dr. M a r t i n Adamson f o r b e i n g a r g u m e n t a t i v e , R i c h a r d O'Grady f o r h i s p a t i e n t a s s i s t a n c e over the p a s t t h r e e y e a r s and f o r s u g g e s t i n g f i g u r e 25, and my s u p e r v i s o r , Dr. D a n i e l R. B r o o k s , f o r s t i m u l a t i n g my i n t e r e s t i n p a r a s i t o l o g y and c l a d i s t i c s , and f o r h i s guidance d u r i n g the c o u r s e of t h i s i n v e s t i g a t i o n . F i n a l l y , I would l i k e t o thank my husband, K e i t h , f o r h i s c o n s t a n t s u p p o r t and encouragement. 1 INTRODUCTION Members of the genus T e l o r c h i s Luehe, 1899 a r e p l a g i o r c h i f o r m i n t e s t i n a l p a r a s i t e s o c c u r r i n g w o r l d w i d e . They ar e common i n h a b i t a n t s of N o r t h American f r e s h w a t e r t u r t l e s and, o c c a s i o n a l l y , snakes and salamanders. T e l o r c h i i d s a re c h a r a c t e r i z e d by h a v i n g t e s t e s a t the p o s t e r i o r end of the body, and by p o s s e s s i n g an ovary t h a t i s p r e t e s t i c u l a r and s e p a r a t e d from the t e s t e s by e x t e n s i v e u t e r i n e c o i l i n g (Brooks et a l . , 1985) . From a s y s t e m a t i c s t a n d p o i n t , T e l o r c h i s i s a p r o b l e m a t i c a l group. One p o i n t of c o n t e n t i o n i s t h e nomenclature of the group. Luehe (1899) proposed T e l o r c h i s , w i t h T. c l a v a as t y p e . One day l a t e r , Looss (1899) a l s o proposed the genus T e l o r c h i s , but w i t h T. l i n s t o w i as t y p e . Luehe (1900) l a t e r d i v i d e d T e l o r c h i s i n t o two subgenera - T. ( T e l o r c h i s ) w i t h T. c l a v a as t y p e and T. ( C e r c o r c h i s ) w i t h T. l i n s t o w i as t y p e . T h i s d i v i s i o n was based on the f o l l o w i n g c h a r a c t e r s : g e n i t a l pore c l o s e t o and i n f r o n t of v e n t r a l s u c ker i n C e r c o r c h i s , g e n i t a l pore somewhat d i s t a n t and t o the l e f t of the v e n t r a l s u c ker i n T e l o r c h i s ; t e s t e s i n more or l e s s s t r i c t tandem a t the p o s t e r i o r end i n C e r c o r c h i s , t e s t e s o b l i q u e or n e a r l y tandem, midway between the g e n i t a l a p e r a t u r e and the p o s t e r i o r end i n T e l o r c h i s ( P e r k i n s , 1928; Wharton, 1940). S u b s e q u e n t l y , the genus C e r c o r c h i s has been r e c o g n i z e d as an independent genus by some a u t h o r s ( B e n n e t t , 1935; Bennett and Sharp, 1938; Bennett and T o b i e , 1936; B y r d , 1937; G o l d b e r g e r , 1911; McMullen, 1934; McMullen and Roudabush, 1936; P e r k i n s , 2 1928; Z e l i f f , 1937) and r e j e c t e d as s u p e r f l u o u s by o t h e r s ( S t u n k a r d , 1915; D o l l f u s , 1929; Wharton, 1940). However, th e s e d i f f e r e n c e s do not seem t o be g e n e r i c i n n a t u r e because both m o r p h o l o g i e s can be observed w i t h i n a s i n g l e s p e c i e s . C o n s i d e r i n g the o r i g i n a l s e p a r a t i o n t o have been based on c h a r a c t e r s t h a t have been shown t o v a r y w i t h i n a s i n g l e s p e c i e s , r e c e n t workers (Yamaguti, 1958; C a b l e and Sanborn, 1970; N a s i r , 1974) have tended t o c o n s i d e r C e r c o r c h i s t o be a j u n i o r synonym of T e l o r c h i s . Other genera have a l s o been proposed t o accommodate s i n g l e t e l o r c h i i d s p e c i e s t h a t p o s s e s s unique c h a r a c t e r i s t i c s . B a r k e r and Covey (1911) e r e c t e d P r o t e n e s f o r a s p e c i e s c h a r a c t e r i z e d by h a v i n g a d o r s o l a t e r a l r a t h e r than m e d i a l g e n i t a l p o r e . S t u n k a r d and F r a n z (1977) proposed P a r a t e l o r c h i s , f o r P. a u r i d i s t o m i (synonym T e l o r c h i s a u r i d i s t o m i B y r d , 1937); they d i s t i n g u i s h e d t h i s s p e c i e s a t the g e n e r i c l e v e l because i t has a n t e r o l a t e r a l l a p p e t s on the o r a l s u c k e r . In b o t h c a s e s above, the d i a g n o s t i c c h a r a c t e r i s t i c s of the genera a r e autapomorphies, t r a i t s t h a t a r e r e s t r i c t e d t o a s i n g l e s p e c i e s . Autapomorphies can be used t o c h a r a c t e r i z e a s p e c i e s , but do not j u s t i f y placement i n a new genus when t h e r e a r e s u f f i c i e n t synapomorphies d i a g n o s i n g the o l d genus (Hennig, 1966; W i l e y , 1981). Yamaguti (1971) proposed P s e u d o t e l o r c h i s f o r P. compactus (synonym T e l o r c h i s compactus Cable and Sanborn, 1970). Due t o i t s unusual morphology, the taxonomic s t a t u s of t h i s s p e c i e s i s u n c e r t a i n (I w i l l d i s c u s s t h i s s p e c i e s l a t e r ) . The second problem i s t h a t the group i s n o t o r i o u s f o r i t s 3 i n t r a s p e c i f i c m o r p h o l o g i c a l v a r i a t i o n . T h i s has l e d t o some disagreement about the number of s p e c i e s i n the genus. Extreme v a r i a b i l i t y , c o u p l e d w i t h a l a c k of e x p e r i m e n t a l work t o determine the e x t e n t of h o s t - i n d u c e d v a r i a t i o n , has r e s u l t e d i n a tendency by some t a x o n o m i s t s t o d e s c r i b e a new s p e c i e s f o r every specimen t h a t e x h i b i t s the s l i g h t e s t v a r i a t i o n , or f o r o t h e r s t o propose e x t e n s i v e synonymies. Two p r e v i o u s e x t e n s i v e taxonomic r e v i s i o n s (Wharton, 1940; N a s i r , 1974) have h e l p e d t o d i s p e l some of the problems a s s o c i a t e d w i t h T e l o r c h i s , but have f a i l e d t o r e s o l v e the taxonomy e n t i r e l y . N e i t h e r a u t h o r examined many of the type specimens and thus the s t u d i e s l a c k the i n f o r m a t i o n t h a t would have a l l o w e d them t o produce a more i n c l u s i v e l i s t of synonymies. In a d d i t i o n , ' W a t e r t o r ' s (1967) study on h o s t -induced v a r i a t i o n has demonstrated the u n s u i t a b i l i t y of some c h a r a c t e r s p r e v i o u s l y used t o d i s t i n g u i s h s p e c i e s . These c h a r a c t e r s w i l l be d i s c u s s e d more e x t e n s i v e l y i n the r e s u l t s s e c t i o n . In the p r e s e n t s t u d y , t e n of the t h i r t y d e s c r i b e d N o r t h American s p e c i e s of T e l o r c h i s a r e c o n s i d e r e d v a l i d . T h i s assessment was based on the e x a m i n a t i o n of a l l a v a i l a b l e type specimens, as w e l l as voucher specimens d e p o s i t e d i n the U.S. N a t i o n a l Museum and H.W. Manter Lab H e l m i n t h o l o g i c a l c o l l e c t i o n s . E x a m i n a t i o n of these specimens made i t p o s s i b l e t o dete r m i n e any p r e v i o u s l y r e p o r t e d f e a t u r e s t h a t were f i x a t i o n a r t i f a c t s and t o f i n d new c h a r a c t e r s of taxonomic use. In a d d i t i o n , the i n f o r m a t i o n on i n t r a s p e c i f i c m o r p h o l o g i c a l 4 v a r i a t i o n among t e l o r c h i i d s p r o v i d e d by W a t e r t o r (1967) was used t o h e l p d e t e r m i n e s p e c i e s membership. A taxonomic r e v i s i o n of T e l o r c h i s u s i n g p h y l o g e n e t i c s y s t e m a t i c s has never been a t t e m p t e d . The major purpose of a p h y l o g e n e t i c c l a s s i f i c a t i o n i s t o condense and summarize the i n f e r r e d h i s t o r y of s p e c i a t i o n as r e f l e c t e d by hypotheses of t h a t h i s t o r y ( W i l e y , 1981). T h i s type of a n a l y s i s i s u s e f u l not o n l y as a means of f o r m u l a t i n g hypotheses about 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 , but a l s o as a means of i n v e s t i g a t i n g e v o l u t i o n a r y q u e s t i o n s i n d e v e l o p m e n t a l b i o l o g y ( F i n k , 1982), biogeography (Ne l s o n and P l a t n i c k , 1981), s p e c i a t i o n ( W i l e y , 1981), c o e v o l u t i o n , and e v o l u t i o n a r y e c o l o g y ( B r o o k s , 1985a). F o l l o w i n g a number of s t u d i e s t h a t c o n c l u d e d t h a t c o e v o l u t i o n i s a p r e v a i l i n g p a t t e r n i n p a r a s i t e s p e c i a t i o n ( e.g. Dougherty, 1949; H a r r i s o n , 1914; Hop k i n s , 1942; M e t c a l f , 1929), the phenomenon of h o s t - p a r a s i t e c o e v o l u t i o n has r e c e n t l y become t o p i c a l ( e.g. Futuyma and S l a t k i n , 1983; Wheeler and B l a c k w e l l , 1984). Two c o n c e p t s of c o e v o l u t i o n appeared i n d e p e n d e n t l y and n e a r l y s i m u l t a n e o u s l y i n s y s t e m a t i c s and e c o l o g y ( B r o o k s , 1985b). One of the s e c o n c e p t s d e f i n e s c o e v o l u t i o n i n an a d a p t i v e sense by examining the r e c i p r o c a l response between ho s t and p a r a s i t e . However, any e x p l a n a t i o n of the 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 r e c i p r o c a l response p a t t e r n s r e q u i r e s an e s t i m a t e of how l o n g the h o s t - p a r a s i t e a s s o c i a t i o n s have e x i s t e d . Recent s t u d i e s have d e f i n e d c o e v o l u t i o n i n a p h y l o g e n e t i c sense by examining h o s t - p a r a s i t e r e l a t i o n s h i p s f o r p a t t e r n s of 5 congruence; t h e s e p a t t e r n s a r e b e l i e v e d t o be the r e s u l t of l o n g - s t a n d i n g 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 between the host group and the p a r a s i t e group. Congruence between ho s t and p a r a s i t e phylogeny i s g e n e r a l l y assumed t o be the r e s u l t of commonly e x p e r i e n c e d a l l o p a t r i c e v e n t s . C o n v e r s e l y , the p a r a s i t e may occur i n a g i v e n h o s t because i t has c o l o n i z e d t h a t host from another u n r e l a t e d h o s t ( B r o o k s , 1981). By comparing the h y p o t h e s i z e d host and p a r a s i t e p h y l o g e n i e s , i t i s p o s s i b l e t o e s t i m a t e how much of the e v o l u t i o n of T e l o r c h i s can be a t t r i b u t e d t o c o e v o l u t i o n , and how much t o c o l o n i z a t i o n . MATERIALS AND METHODS Whole mount specimens, most s t a i n e d w i t h h a e m a t o x y l i n and mounted i n Canada balsam, were o b t a i n e d from the U.S. N a t i o n a l Museum H e l m i n t h o l o 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), and the H.W. Manter L a b o r a t o r y , U n i v e r s i t y of Nebraska (HWML). Specimens of a l l d e s c r i b e d N o r t h American s p e c i e s were a v a i l a b l e e x c ept T e l o r c h i s s t e n o u r a I n g l e s , 1930, which has been l o s t from the USNM c o l l e c t i o n (Ms. P. P i l i t t , p e r s o n a l communication). The h o s t s and l o c a l i t i e s l i s t e d i n the s p e c i e s d i a g n o s e s i n the r e s u l t s s e c t i o n a r e o n l y those t h a t have been c o n f i r m e d by the e x a m i n a t i o n of specimens. Unconfirmed r e c o r d s a r e l i s t e d i n the remarks s e c t i o n f o l l o w i n g each d i a g n o s i s . C h a r a c t e r d a t a used f o r 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 by both l i t e r a t u r e s e a r c h and the e x a m i n a t i o n of specimens. A l l specimens were examined w i t h a l i g h t m i c r o s c o p e . Measurements from t h o s e specimens t h a t were immature, f o l d e d , 6 t o r n , c o n t r a c t e d , or i n o t h e r w i s e poor c o n d i t i o n were not i n c l u d e d i n the a n a l y s e s . However, a l l specimens were examined t o p r o v i d e i n f o r m a t i o n on i n t r a s p e c i f i c v a r i a t i o n . Measurements ar e g i v e n i n mi c r o m e t e r s u n l e s s o t h e r w i s e n o t e d . Drawings were p r e p a r e d w i t h the a i d of a drawing tube. The r e l a t i v e degree of p l e s i o m o r p h y and apomorphy f o r the t r a n s f o r m a t i o n s e r i e s was de t e r m i n e d by u s i n g the outgroup method of comparison (see Lundberg, 1972; W i l e y , 1981). The outgroup used was the f a m i l y Ochetosomatidae, a group of digeneans t h a t a r e found i n the d i g e s t i v e t r a c t of r e p t i l e s , and have been c o n s i d e r e d t o be c l o s e l y r e l a t e d t o T e l o r c h i s (Byrd and Denton, 1938). In a d d i t i o n , c h a r a c t e r s common t o the P l a g i o r c h i i f o r m e s were p o l a r i z e d u s i n g the p h y l o g e n e t i c a n a l y s i s of the Digenea sensu Brooks e t a_l. (1985). Q u a n t i t a t i v e a n a l y s e s were c a r r i e d out u s i n g p h y l o g e n e t i c s y s t e m a t i c s (sensu Hennig, 1966) and the PHYSYS computer program d e v e l o p e d by James S. F a r r i s and Mary F. M i c k e v i c h . For c h a r a c t e r s which were d i f f i c u l t t o p o l a r i z e u s i n g the o u t g r o u p s , p o l a r i t i e s were d e t e r m i n e d by the f u n c t i o n a l outgroup method (Watrous and Wheeler, 1981). The f i t of each t r a n s f o r m a t i o n s e r i e s was a s s e s s e d w i t h 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). CHARACTER ANALYSIS C h a r a c t e r numbers i n p a r e n t h e s e s f o l l o w i n g each c h a r a c t e r name r e f e r t o columns i n the d a t a m a t r i x i n t a b l e I . The p l e s i o m o r p h i c , or p r i m i t i v e s t a t e i s i n d i c a t e d by the code 0. For a l l c h a r a c t e r s , the outgroup p o s s e s s e s the p l e s i o m o r p h i c 7 c o n d i t i o n . T B L = t o t a l body l e n g t h ; a l l measurements f o l l o w e d by t h i s n o t a t i o n a r e g i v e n as a pe r c e n t a g e of the t o t a l body l e n g t h of the specimens. 1. BODY SHAPE ( c h a r a c t e r 1). T e l o r c h i i d s e x h i b i t t h r e e body shapes; o v a l or l i n g u i f o r m , e l o n g a t e , or f i l i f o r m [see f i g u r e 1 ] . Body shape seems t o have been a p l a s t i c c h a r a c t e r i n digenean e v o l u t i o n . The i n t e r p r e t a t i o n which p r o v i d e s the best f i t t o the o t h e r d a t a i s t h a t the p l e s i o m o r p h i c c o n d i t i o n i s o v a l / l i n g u i f o r m ( 0 ) ; the e l o n g a t e body form i s d e r i v e d from t h a t (1) , w i t h the f i l i f o r m c o n d i t i o n b e i n g the most h i g h l y d e r i v e d (2) . 2. BODY LENGTH ( c h a r a c t e r 2 ) . T e l o r c h i i d s f a l l i n t o two g e n e r a l c a t e g o r i e s of body l e n g t h . Those s p e c i e s t h a t are c o n s i d e r e d " s h o r t " never exceed 4.5 mm as o v i g e r o u s a d u l t s ; the average body l e n g t h i s about 3.2 mm. The " l o n g " s p e c i e s always exceed 4.8 mm as o v i g e r o u s a d u l t s . The average body l e n g t h f o r the s e s p e c i e s i s about 7.9 mm. The s h o r t e r body 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 l o n g e r body i s the apomorphic c o n d i t i o n ( 1 ) . A l t h o u g h body l e n g t h may v a r y c o n s i d e r a b l y w i t h age, worm burden, or h o s t , t h i s c o n s e r v a t i v e e s t i m a t e i s c o n s i d e r e d t o be f a i r l y r e p r e s e n t a t i v e of the average body l e n g t h . 3. BODY PROPORTIONS ( c h a r a c t e r 3 ) . Most t e l o r c h i i d s have a r a t i o of body l e n g t h t o w i d t h g r e a t e r than 4:1. Ochetosomatids and most o t h e r p l a g i o r c h i f o r m s have r a t i o s of l e s s than 4:1. T e l o r c h i s s i r e n i s a l s o has a r a t i o of body l e n g t h t o body w i d t h of l e s s than 4:1, and t h a t i s c o n s i d e r e d t o be the p l e s i o m o r p h i c c o n d i t i o n ( 0 ) . A r a t i o of g r e a t e r than 4:1 8 i s the d e r i v e d c o n d i t i o n ( 1 ) . 4. ORAL SUCKER LAPPETS ( c h a r a c t e r 4)". The o r a l s u c k e r of most d i g e n e a n s , i n c l u d i n g most t e l o r c h i i d s , i s c i r c u l a r or s u b c i r c u l a r w i t h o u t m o d i f i c a t i o n s ( 0 ) . The presence of outgrowths of the sucker m a r g i n s , such as the a n t e r o l a t e r a l l a p p e t s of T. a u r i d i s t o m i [see f i g u r e 10], i s an autapomorphy ( 1 ) . 5. PHARYNGEAL GLANDS ( c h a r a c t e r 5 ) . S m a l l p h a r y n g e a l g l a n d s are p r e s e n t i n a l l t e l o r c h i i d s ( 0 ) . The e n l a r g e d , t h i c k e n e d g l a n d s c h a r a c t e r i s t i c of T e l o r c h i s c h e l o p i [see f i g u r e 13] a r e c o n s i d e r e d autapomorphic ( 1 ) . 6. ESOPHAGUS ( c h a r a c t e r 6 ) . The c e c a l b i f u r c a t i o n of T e l o r c h i s r o b u s t u s i s i m m e d i a t e l y p o s t p h a r y n g e a l [see f i g u r e 14]; a l l o t h e r members of the genus p o s s e s s a t l e a s t a s h o r t esophagus, 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 digeneans ( 0 ) . The l a c k of an esophagus appears t o be autapomorphic ( 1 ) . 7. CECAL BIFURCATION ( c h a r a c t e r 7 ) . For o c h e t o s o m a t i d s and most p l a g i o r c h i f o r m s the c e c a l b i f u r c a t i o n i s more than 6% TBL from the a n t e r i o r end.of the body ( 0 ) . Among t e l o r c h i i d s , when the c e c a l b i f u r c a t i o n i s l e s s than 6% TBL from the a n t e r i o r end, i t i s c o n s i d e r e d t o be an apomorphic t r a i t ( 1 ) . 8. CECAL EPITHELIUM ( c h a r a c t e r 8 ) . W i t h one e x c e p t i o n , the l i n i n g of the cecum has a u n i f o r m t h i c k n e s s ; t h i s i s the c o n d i t i o n f o r o c h e t o s o m a t i d s and most o t h e r p l a g i o r c h i f o r m s , and 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 e l o r c h i s c h e l o p i p o s s e s s e s n o t i c e a b l y t h i c k e n e d e p i t h e l i u m a t the p o i n t of b i f u r c a t i o n [see f i g u r e 13], which i s an autapomorphy f o r t h i s s p e c i e s ( 1 ) . 9 9. SUCKER RATIO ( c h a r a c t e r 9 ) . Most p l a g i o r c h i f o r m s p o s s e s s v e n t r a l s u c k e r s t h a t a r e about the same w i d t h as the o r a l s u c k e r s . The range of r a t i o s of o r a l s u c k e r w i d t h t o a c e t a b u l a r w i d t h f o r most t e l o r c h i i d s i s 1:0.47-0.97, a v e r a g i n g about 1:0.75. In a few s p e c i e s , the range of s u c k e r r a t i o s i s 0.86-1:1, w i t h an average of 1:1. The l a t t e r 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 ) , the f o rmer, apomorphic ( 1 ) . 10. POSITION OF TESTES ( c h a r a c t e r 10). Among p l a g i o r c h i i f o r m s , the t e s t e s a r e p r i m i t i v e l y o b l i q u e or s y m m e t r i c a l and p o s i t i o n e d i n the mid-hindbody ( 0 ) . T e l o r c h i i d s have tandem t e s t e s p o s i t i o n e d near the p o s t e r i o r end of the body, which i s c o n s i d e r e d apomorphic ( 1 ) . 11. MUSCULARITY OF THE CIRRUS SAC ( c h a r a c t e r 11). Two c i r r u s sac m o r p h o l o g i e s a r e o b s e r v e d . Most t e l o r c h i i d s have l o n g , t h i n c i r r u s s a c s , the c o n d i t i o n seen i n most of the o u t g r o u p s ( 0 ) . The p o s s e s s i o n of a c i r r u s sac w i t h markedly t h i c k e n e d muscular w a l l s , seen i n T. c h e l o p i and T. scabrae [see f i g u r e 2 ] , i s apomorphic ( 1 ) . 12. CIRRUS SAC POSITION ( c h a r a c t e r s 12 and 13). A l t h o u g h the c i r r u s sac does not always end i n e x a c t l y the same p o s i t i o n i n any one s p e c i e s , t h e r e a r e d e f i n i t e b o u n d a r i e s w i t h i n which i t i s c o n s i s t e n t l y found. These p o s i t i o n s a r e s p e c i f i c t o c e r t a i n s p e c i e s of T e l o r c h i s [see f i g u r e 3 ] . One p o s i t i o n i s the a r e a around the o v a r y . The c i r r u s sac may end anywhere from one o v a r i a n l e n g t h a n t e r i o r t o the o v a r y , t o j u s t p o s t e r i o r t o the o v a r y . T h i s p o s i t i o n i s the most common one among the o u t g r o u p s and among t e l o r c h i i d s , and i s c o n s i d e r e d t o be the 10 p l e s i o m o r p h i c s t a t e ( 0 , 0 ) . Two s t a t e s a r e c o n s i d e r e d t o be i n d e p e n d e n t l y d e r i v e d from the p l e s i o m o r p h i c s t a t e . One p o s i t i o n i s 1/2 t o 2/3 of the d i s t a n c e from the acetabulum t o the ovary ( 0 , 1 ) . T h i s p a r t i c u l a r s t a t e i s found i n T. scabrae and T. a t t e n u a t u s . The o t h e r p o s i t i o n i s a t the a c e t a b u l a r l e v e l . T h i s i s a l s o a d e r i v e d c o n d i t i o n ( 1 , 0 ) , and i s found i n T. an g u s t u s . 13. GENITAL PORE POSITION ( c h a r a c t e r s 14 and 15). The p l e s i o m o r p h i c g e n i t a l pore p o s i t i o n f o r a l l digeneans i s p r e a c e t a b u l a r and median or s l i g h t l y l e f t ( 0 , 0 ) . T h i s c o n d i t i o n i s p r e s e n t i n most s p e c i e s of T e l o r c h i s . The g e n i t a l pore may a l s o be v e n t r a l t o the l e f t cecum or d o r s o l a t e r a l t o the l e f t cecum [see f i g u r e 4 ] , As t h e r e i s no e v i d e n c e t o suggest t h a t e i t h e r of t h e s e o t h e r two c h a r a c t e r s t a t e s e v o l v e d from the o t h e r , and t h e t a x a they a r e found i n a r e more c l o s e l y r e l a t e d t o o t h e r s p e c i e s than they a r e t o each o t h e r , they a r e c o n s i d e r e d t o have e v o l v e d i n d e p e n d e n t l y from the p r i m i t i v e c o n d i t i o n . T e l o r c h i s s c a b r a e has a g e n i t a l pore v e n t r a l t o the l e f t cecum ( 0 , 1 ) ; the g e n i t a l pore of T. angustus i s d o r s o l a t e r a l t o the l e f t cecum ( 1 , 0 ) . 14. POSITION OF OVARY ( c h a r a c t e r 16). The p l e s i o m o r p h i c c o n d i t i o n i s f o r the ovary t o be c l o s e r t o the acetabulum than t o the t e s t e s ( 0 ) . Two s p e c i e s , T e l o r c h i s s i n g u l a r i s and T. a t t e n u a t u s , have the ova r y c l o s e r t o the t e s t e s than the acetabulum; t h i s i s the apomorphic c o n d i t i o n ( 1 ) . 15. UTERINE CONFIGURATION ( c h a r a c t e r 17). A l l s p e c i e s of T e l o r c h i s have a u t e r u s w i t h c o i l e d a s c e n d i n g and d e s c e n d i n g 11 l o o p s , s e p a r a t i n g t h e ovary from the t e s t e s [see f i g u r e 5 ] ; t h i s i s a synapomorphy f o r the genus. The p l e s i o m o r p h i c t r a i t , found i n the outgroup, i s an i r r e g u l a r l y c o i l e d sac ( 0 ) ; the former c o n d i t i o n i s apomorphic ( 1 ) . 16. METRATERM BULB ( c h a r a c t e r 18). The presence of a muscular b u l b on the metraterm i n T. s i n g u l a r i s [see f i g u r e 15] i s autapomorphic ( 1 ) . Absence i s p l e s i o m o r p h i c (0) f o r d i g e n e a n s . 17. GENITAL ATRIUM ( c h a r a c t e r 19). T e l o r c h i s s i n q u l a r i s p o s s e s s e s a g e n i t a l a t r i u m [see f i g u r e 15], a chamber t h a t r e c e i v e s the openings from the male and female r e p r o d u c t i v e d u c t s and opens on the body s u r f a c e t h r o u g h a g e n i t a l pore ( S c h e l l , 1970). The p l e s i o m o r p h i c c o n d i t i o n , found i n a l l o t h e r t e l o r c h i i d s , i s f o r the metraterm and c i r r u s sac t o meet a t or near the g e n i t a l pore ( 0 ) ; p o s s e s s i o n of a g e n i t a l a t r i u m i s t h e r e f o r e a unique t r a i t ( 1 ) . 18. STRUCTURE OF VITELLINE FOLLICLES ( c h a r a c t e r 2 0 ) . V i t e l l i n e f o l l i c l e s a r e e i t h e r i n l a t e r a l , c l u s t e r e d g roups, or i n two c o n t i n u o u s l a t e r a l bands [see f i g u r e 6 ] , The c l u s t e r c o n f o r m a t i o n , commonly found i n o c h e t o s o m a t i d 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 ) , the c o n t i n u o u s rows apomorphic ( 1 ) . CHARACTERS NOT INCLUDED IN THE ANALYSIS W a t e r t o r (1967) r e c o g n i z e d t h a t w i t h o u t knowing which c h a r a c t e r i s t i c s a r e l i k e l y t o e x h i b i t i n t r a s p e c i f i c v a r i a t i o n , i t would be i m p o s s i b l e t c r e v i s e T e l o r c h i s . In o r d e r t o i d e n t i f y t h e s e c h a r a c t e r s , she e x p e r i m e n t a l l y i n f e c t e d a number 1 2 of s p e c i e s of salamander and t u r t l e h o s t s w i t h T e l o r c h i s  b o n n e r e n s i s W a i t z , 1960. Her e x p e r i m e n t s showed t h a t many of the c h a r a c t e r s t h a t had been used t o d i f f e r e n t i a t e between s p e c i e s were p l a s t i c , even among specimens taken from the same host s p e c i e s . O b s e r v a t i o n s made d u r i n g the c o u r s e of t h i s study c o n f i r m W a t e r t o r ' s s u g g e s t i o n t h a t such v a r i a b i l i t y was not r e s t r i c t e d t o a few s p e c i e s of T e l o r c h i s . A l i s t of c h a r a c t e r i s t i c s t h a t a r e h i g h l y v a r i a b l e and u n s u i t e d f o r s y s t e m a t i c a n a l y s i s has been produced. T h i s l i s t of c h a r a c t e r s , a l o n g w i t h j u s t i f i c a t i o n f o r t h e i r e x c l u s i o n , f o l l o w s . 1. ANTERIOR EXTENT OF VITELLARIA. The v i t e l l i n e f o l l i c l e s may e x t e n d a n t e r i o r l y t o anywhere between the ov a r y and acetabulum. They w i l l a l s o o c c a s i o n a l l y e x t e n d as f a r as the l e v e l of t h e a n t e r i o r margin of the acetabulum. of the acetabulum. 2. LOCATION OF OVARY. Whether or not the ovary i s c l o s e r t o the acetabulum or t e s t e s does not v a r y w i t h i n a s p e c i e s , but the e x a c t l o c a t i o n may v a r y c o n s i d e r a b l y . 3. SIZE OF SUCKERS. S i n c e the s u c k e r s f r e q u e n t l y c o n t r a c t d u r i n g f i x a t i o n , t h i s i s not a r e l i a b l e c h a r a c t e r . 4. LENGTH OF ESOPHAGUS. A l t h o u g h p r e s e n c e or absence of an esophagus i s a r e l i a b l e t r a i t , the a c t u a l l e n g t h w i l l v a r y . Esophageal l e n g t h i s p a r t i c u l a r l y a f f e c t e d by c o n t r a c t i o n of the worms d u r i n g f i x a t i o n . 5. EGG SIZE. W i t h i n a s i n g l e s p e c i e s , eggs may v a r y by as much as 10 micr o m e t e r s i n l e n g t h . They a l s o seem t o v a r y w i t h the age of the worm. 1 3 6. BODY WIDTH. Body w i d t h can va r y c o n s i d e r a b l y w i t h age of the p a r a s i t e , and i f t h e r e i s c o n t r a c t i o n of the body. 7. TESTES CONTIGUOUS OR NOT. The p o s t e r i o r end of the specimens i s f r e q u e n t l y c o n t r a c t e d or pushed outward d u r i n g f i x a t i o n and mounting, c a u s i n g the p o s i t i o n of the t e s t e s t o v a r y . 8. PHARYNX SIZE. The pharynx, b e i n g m u s c u l a r , may c o n t r a c t d u r i n g f i x a t i o n , c a u s i n g a v a r i a t i o n i n s i z e from specimen t o specimen. 9. PERCENTAGE FOREBODY. The pe r c e n t a g e f o r e b o d y r e f e r s t o the p e r c e n t a g e of the t o t a l body l e n g t h t h a t i s a n t e r i o r t o the acetabulum. The p o s i t i o n of the acetabulum may v a r y by as much as 18% of the t o t a l body l e n g t h i n a s i n g l e s p e c i e s . A v a r i a t i o n of 2-5% TBL i s t h e r e f o r e not a d i s t i n g u i s h i n g c h a r a c t e r i s t i c . 10. POSTERIOR EXTENT OF CIRRUS SAC. There a r e t h r e e d i s t i n c t a r e a s t o which the c i r r u s sac may e x t e n d : t o the o v a r i a n l e v e l , midway between acetabulum and o v a r y , and t o the a c e t a b u l a r l e v e l . W i t h i n t h e s e a r e a s , the e x a c t l o c a t i o n w i l l v a r y . For example, a t the o v a r i a n l e v e l , the c i r r u s sac may end anywhere from one o v a r i a n l e n g t h a n t e r i o r t o the ova r y t o j u s t p o s t e r i o r t o the o v a r y . 11. RATIO OF SUCKER WIDTH TO PHARYNGEAL WIDTH. The r a t i o of the o r a l s u c k e r t o the pharynx, or the acetabulum t o the pharynx, i s o f t e n used t o d i s t i n g u i s h between s p e c i e s . However, the ranges of t h e s e r a t i o s o v e r l a p t o such an e x t e n t , t h a t they c o u l d not be used t o c h a r a c t e r i z e s p e c i e s (see t a b l e I I ) . 14 RESULTS TAXONOMIC REVISION T h i r t y s p e c i e s of T e l o r c h i s have been d e s c r i b e d from N o r t h American salamanders, snakes, and t u r t l e s . When the c h a r a c t e r i s t i c s found t o be i n t r a s p e c i f i c a l l y v a r i a b l e a r e not used t o d i s t i n g u i s h between s p e c i e s , o n l y t e n of th e s e t h i r t y s p e c i e s can be c o n s i d e r e d t o be v a l i d . D i a g n o s i s of t h e s e t en s p e c i e s f o l l o w s . T e l o r c h i s s i r e n i s Z e l i f f , 1937 [ f i g u r e 7] SYNONYMS: C e r c o r c h i s s i r e n i s Z e l i f f , 1937. HOSTS: S i r e n l a c e r t i n a L i n n e , 1766, G r e a t e r s i r e n ; Amphiuma  t r i d a c t y l u m C u v i e r , 1827, t h r e e - t o e d Amphiuma. LOCALITIES: t y p e l o c a l i t y g i v e n as " s o u t h e a s t e r n U.S."; R e e l f o o t Lake, Tenn. SPECIMENS MEASURED: 7, USNM Helm. C o l l . Nos. 9396, 9400. TAXONOMIC CHARACTERISTICS: Body l i n g u i f o r m , 2.2-3.1 mm l o n g ; r a t i o of l e n g t h t o w i d t h 2.6-3.8:1 (x=3.1:1). O r a l s u c k e r 184-216 i n d i a m e t e r . Pharynx 78-82 i n d i a m e t e r ; r a t i o of o r a l s u c k er w i d t h t o pharynx w i d t h 1:0.42-0.43 (x=1:0.43). Esophagus 8-67 l o n g , 0.2-0.7% TBL. C e c a l b i f u r c a t i o n 9-10% TBL from a n t e r i o r end; ceca e x t e n d j u s t p o s t e r i o r t o t e s t e s , 5-6% TBL from p o s t e r i o r end. Acetabulum 192-216 i n d i a m e t e r . Forebody 15-21% TBL. R a t i o of o r a l s u c ker w i d t h t o a c e t a b u l a r w i d t h 0.87-1:1 (X=0.96:1). 15 T e s t e s e l l i p t i c a l , tandem, c o n t i g u o u s , i n t e r c e c a l ; p o s t t e s t i c u l a r space 7-8% TBL. C i r r u s sac ends partway down t o p o s t e r i o r t o o v a r y . G e n i t a l pore v e n t r a l , p r e a c e t a b u l a r , i n t e r c e c a l , s l i g h t l y l e f t of median. Ovary 15-21% TBL from a n t e r i o r end, i n t e r c e c a l , s p h e r i c a l t o o v o i d . S e m i n a l r e c e p t a c l e and L a u r e r ' s c a n a l not obs e r v e d ; M e h l i s ' g l a n d p r e s e n t . Space o c c u p i e d by u t e r u s 56-57% TBL; metraterm 1/2 l e n g t h of c i r r u s s a c. V i t e l l i n e f o l l i c l e s s e p a r a t e d i n t o c l u s t e r s ; e x t e n d a n t e r i o r l y from h a l f w a y down acetabulum t o midway between acetabulum and o v a r y , p o s t e r i o r l y 9/10 d i s t a n c e o v a r y t o t e s t e s t o h a l f w a y down t e s t e s . Eggs 26-38 l o n g by 15-18 wide. A n t e r i o r e x t e n t of e x c r e t o r y v e s i c l e not o b s e r v e d . REMARKS: The specimens t h a t w e r e • o r i g i n a l l y d e s c r i b e d by Z e l i f f (1937) were found t o be immature. Wharton (1940) a l s o n o t e d t h i s i n h i s r e v i s i o n . Three mature specimens were c o l l e c t e d a t a l a t e r d a t e (USNM Nos. 9396 and 9400). A l l i n f o r m a t i o n used i n the d e s c r i p t i o n and 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 t h o s e t h r e e specimens. T e l o r c h i s s t u n k a r d i C h a n d l e r , 1923 [ f i g u r e 8] SYNONYMS: T e l o r c h i s ( C e r c o r c h i s ) n e c t u r i ( P e r k i n s 1928) Wharton, 1940, new synonym; T e l o r c h i s ( C e r c o r c h i s ) c r y p t o b r a n c h i McMullen and Roudabush, 1936. HOSTS: Amphiuma means Garden, 1821, two-toed Amphiuma; N e c t u r u s  maculosus R a f i n e s q u e , 1818, Mudpuppy; Amphiuma t r i d a c t y l u m 1 6 C u v i e r , 1827, t h r e e - t o e d Amphiuma. LOCALITIES: Baton Rouge, L a . ; Wood's H o l e , Mass.; Washington, D.C. SPECIMENS MEASURED: 5, USNM Helm. C o l l . Nos. 8057, 31761, 70618. TAXONOMIC CHARACTERISTICS: Body e l o n g a t e , 2.5-3.4 mm l o n g ; r a t i o of l e n g t h t o w i d t h 4-4.8:1 (x=4.4:1). O r a l s u c k e r 202-212 i n d i a m e t e r . Pharynx 67-78 i n d i a m e t e r ; r a t i o of o r a l s u c k e r w i d t h t o pharynx w i d t h 1:0.32-0.37 (x=1:0.35). Esophagus 106-180 l o n g , 3-7% TBL. C e c a l b i f u r c a t i o n 12-18% TBL from a n t e r i o r end; ceca e x t e n d j u s t p o s t e r i o r t o t e s t e s , 2-6% TBL from p o s t e r i o r end. Acetabulum 206-243 i n d i a m e t e r . Forebody 22-35% TBL. R a t i o of o r a l s u c ker w i d t h t o a c e t a b u l a r w i d t h 0.86-0.98:1 ( X = 0 . 9 : 1 ) . T e s t e s s p h e r i c a l t o e l l i p t i c a l , tandem, c o n t i g u o u s , i n t e r c e c a l ; p o s t t e s t i c u a l r space 4-7% TBL. C i r r u s sac ends partway down t o j u s t p o s t e r i o r t o o v a r y . G e n i t a l pore v e n t r a l , p r e a c e t a b u l a r , i n t e r c e c a l , s l i g h t l y l e f t of median. Ovary 36-54% TBL from a n t e r i o r end, i n t e r c e c a l , s p h e r i c a l t o o v o i d . S e m i n a l r e c e p t a c l e and L a u r e r ' s c a n a l nor o b s e r v e d ; M e h l i s ' g l a n d p r e s e n t . Space o c c u p i e d by u t e r u s 38-52% TBL; metraterm 2/3 l e n g t h of c i r r u s s a c . V i t e l l i n e f o l l i c l e s s e p a r a t e d i n t o c l u s t e r s ; e xtend a n t e r i o r l y from j u s t p o s t e r i o r t o a cetabulum t o partway down ov a r y , p o s t e r i o r l y 3/4 d i s t a n c e from ovary t o t e s t e s t o i m m e d i a t e l y p r e t e s t i c u l a r . Eggs 41 l o n g by 18 wide. A n t e r i o r e x t e n t of e x c r e t o r y v e s i c l e from o v a r i a n l e v e l t o 1 7 between acetabulum and o v a r y . REMARKS: McMullen and Roudabush (1936) d e s c r i b e d C e r c o r c h i s  c r y p t o b r a n c h i from C r y p t o b r a n c h u s a l l e q a n i e n s i s Daudin, 1822 c o l l e c t e d a t Ames, Iowa. T e l o r c h i s n e c t u r i has been r e p o r t e d from Graptemys pseudoqeographica Gray, 1831 from Nebraska, HWML #20213 (Brooks and Mayes, 1976). A d d i t i o n a l l y , T. s t u n k a r d i has been r e p o r t e d from S i r e n l a c e r t i n a L i n n e , 1766 i n the v i c i n i t y of Mia m i , F l o r i d a , HWML #20327 (Brooks and Buckner, 1976) and from Amphiuma t r i d a c t y l u m C u v i e r , 1827 and Amphiuma means Garden, 1821 from Payne's P r a i r i e , F l o r i d a and Ocean S p r i n g s , M i s s i s s i p p i (Brooks and Fusco, 1978). P e r k i n s (1928) c l a i m e d t h a t a l t h o u g h T e l o r c h i s n e c t u r i and T. s t u n k a r d i were s i m i l a r i n appearance, the two s p e c i e s were d i s t i n c t from each o t h e r . However, he d i d not l i s t any c h a r a c t e r s by whic h they d i f f e r e d , or p r o v i d e any s o r t of j u s t i f i c a t i o n f o r t h i s s t a t e m e n t . E x a m i n a t i o n of type specimens has shown t h a t t hey d i f f e r o n l y i n a n t e r i o r e x t e n t of v i t e l l i n e f o l l i c l e s , egg s i z e , s u c k er s i z e , and body w i d t h , a l l c h a r a c t e r s which have been shown t o have i n t r a s p e c i f i c v a r i a t i o n . T e l o r c h i s c o r t i S t u n k a r d , 1915 [ f i g u r e 9] SYNONYMS: T e l o r c h i s ( C e r c o r c h i s ) l i n s t o w i G o l d b e r g e r , 1911; T e l o r c h i s l o b o s u s S t u n k a r d , 1915; T e l o r c h i s g u t t a t i MacCallum, 1919; T e l o r c h i s i n s c u l p t i MacCallum, 1919; T e l o r c h i s p a l l i d u s MacCallum, 1919; T e l o r c h i s angustus MacCallum, 1921; T e l o r c h i s  s t e n o u r a I n g l e s , 1930; T e l o r c h i s ( C e r c o r c h i s ) texanus Harwood, 18 1932; T e l o r c h i s medius McMullen, 1934; T e l o r c h i s b o n n e r e n s i s W a i t z , 1960, new synonym. HOSTS: Chrysemys s c r i p t a e l e g a n s Wied, 1839, r e d - e a r e d t u r t l e ; Ambystoma macrodactylum B a i r d , 1849, l o n g - t o e d salamander; Chrysemys p i c t a S c h n e i d e r , 1873, p a i n t e d t u r t l e ; C h e l y d r a  s e r p e n t i n a L i n n e , 1758, snapping t u r t l e ; S t e r n o t h e r u s c a r i n a t u s Gray, 1856, k e e l - b a c k e d musk t u r t l e ; S t e r n o t h e r u s o d o r a t u s L a t r e i l l e , 1801, common musk t u r t l e . LOCALITIES: Havana, 111.; C l a r k F o r k , Bonner Co., Idaho; Lake Conway, A r k a n s a s ; Rosenton, Texas; T u s c a l o s a , A l a . ; Washington, D.C; A r l i n g t o n , Va.; H u n t s v i l l e , Texas; Walker, Iowa; R a l e i g h , N.C.; Unknown (New York Aquarium). SPECIMENS MEASURED: 24, USNM Helm. C o l l . Nos. 28299, 30890, 30891, 36172, 36178, 36424, 39415, 43404, 52846, 51849, 51850, 74844. TAXONOMIC CHARACTERISTICS: Body e l o n g a t e , 2.2-4.5 mm l o n g ; r a t i o of l e n g t h t o w i d t h 5.1-11.7:1 (x=7.6:1). O r a l s u c k e r 94-160 i n d i a m e t e r . Pharynx 43-78 i n d i a m e t e r ; r a t i o of o r a l s u c k e r w i d t h to pharynx w i d t h 1:0.41-0.66 (x=1:0.51). Esophagus 39-216 l o n g , 1-5% TBL. C e c a l b i f u r c a t i o n 6-19% TBL from a n t e r i o r end; ceca e x t e n d w e l l p a s t t e s t e s , 1-5% TBL from p o s t e r i o r end. Acetabulum 55-122 i n d i a m e t e r . Forebody 13-28% TBL. R a t i o of o r a l s u c k e r w i d t h t o a c e t a b u l a r w i d t h 1:0.47-0.96 (x=1:0.78). T e s t e s s p h e r i c a l t o o v o i d , tandem, c o n t i g u o u s or n o t , i n t e r c e c a l ; p o s t t e s t i c u l a r space 5-10% TBL. C i r r u s sac ends j u s t a n t e r i o r t o partway down o v e r y . G e n i t a l pore v e n t r a l , p r e a c e t a b u l a r , i n t e r c e c a l , median or s l i g h t l y l e f t of median. 19 Ovary 30-49% TBL from a n t e r i o r end, i n t e r c e c a l , s p h e r i c a l t o o v o i d . S e m i n a l r e c e p t a c l e s m a l l ; L a u r e r ' s c a n a l not o b s e r v e d ; M e h l i s ' g l a n d p r e s e n t . Space o c c u p i e d by u t e r u s 42-58% TBL; metraterm 1/2 t o 2/3 l e n g t h of c i r r u s s a c . V i t e l l i n e f o l l i c l e s c o n t i n u o u s , l a t e r a l bands; e x t e n d a n t e r i o r l y from a n t e r i o r b o r d e r of acetabulum t o a n t e r i o r of o v a r y , p o s t e r i o r l y from 3/4 d i s t a n c e ovary t o t e s t e s t o partway down t e s t e s . Eggs 31-41 l o n g by 14-20 wide. A n t e r i o r e x t e n t of e x c r e t o r y v e s i c l e midway between acetabulum and o v a r y . REMARKS: T h i s s p e c i e s has a l s o been r e p o r t e d from the f o l l o w i n g h o s t s and l o c a l i t i e s : D e i r o c h e l y s r e t i c u l a r i a L a t r e i l l e , 1801, Chrysemys m a r g i n a t a A g a s s i z , 1857, and K i n o s t e r n o n subrubrum Lacepede, 1788, no l o c a l i t y g i v e n (Wharton, 1940); Chrysemys  s c r i p t a e l e g a n s Wied, 1839 from Houston, Texas (Harwood, 1932); Thamnophis s i r t a l i s L i n n e , 1766 from C l a r k F o r k , Idaho ( W a i t z , 1960); Clemmys marmorata B a i r d and G i r a r d , 1852 from O a k l a n d , C a l i f o r n i a ( I n g l e s , 1930); C h e l y d r a s e r p e n t i n a L i n n e , 1758, Graptemys pseudogeographica and Emydoidea b l a n d i n g i H o l b r o o k , 1838 from Nebraska (Brooks and Mayes, 1975); C h e l y d r a  s e r p e n t i n a , Chrysemys s c r i p t a e l e g a n s , and Terrapene C a r o l i n a L i n n e , 1758 from s o u t h e r n I l l i n o i s ( M a r t i n , 1972); Ambystoma  t i g r i n u m Green, 1825 from Idaho ( W a t e r t o r , 1967); and S t e r n o t h e r u s o d o r a t u s L a t r e i l l e , 1801 from L o u i s i a n a (Bennett and Sharp, 1938); K i n o s t e r n o n f l a v e s c e n s from Nebraska, HWML #20212 (Brooks and Mayes, 1976). T e l o r c h i s c o r t i , w i t h ten synonyms, has been the most 20 p r o b l e m a t i c a l s p e c i e s . P a r t of the problem i s t h a t i t i s found i n many d i f f e r e n t h o s t s , and e x h i b i t s extreme v a r i a b i l i t y b o th i n h o s t s of the same s p e c i e s and i n h o s t s of d i f f e r e n t s p e c i e s . I t a l s o does not p o s s e s s any autapomorphies t h a t would make i t im m e d i a t e l y r e c o g n i z a b l e . The c h a r a c t e r i s t i c s used i n the p a s t t o d i f f e r e n t i a t e s p e c i e s a r e tho s e t h a t a re now known t o be p l a s t i c . These i n c l u d e such t r a i t s as the a n t e r i o r and p o s t e r i o r e x t e n t of the v i t e l l i n e f o l l i c l e s , p o s i t i o n of ovary r e l a t i v e t o c i r r u s s a c , suc k e r s i z e , pharynx s i z e , esophagus l e n g t h , body w i d t h , p o s t e r i o r e x t e n t of c e c a , and whether the t e s t e s a r e c o n t i g u o u s or n o t . I t i s a l s o i n t e r e s t i n g t o note t h a t i n the d e s c r i p t i o n of each of t h e s e s p e c i e s , T. c o r t i was always l i s t e d as the most s i m i l a r s p e c i e s . Examined specimens of T. d i m i n u t u s and T. angustus (MacCallum, 1921) were found t o be immature. S t u n k a r d (1915) l i s t e d l o b e d t e s t e s as b e i n g one of the d i s t i n g u i s h i n g c h a r a c t e r i s t i c s f o r T. l o b o s u s , but of the t h r e e specimens examined, o n l y one was found t o e x h i b i t t h i s t r a i t . I t appears t o have been caused by d i s t o r t i o n of the worm when i t was f i x e d or mounted on the s l i d e . T e l o r c h i s b o n n e r e n s i s has been c o n s i d e r e d most s i m i l a r t o T. c o r t i , but was s e p a r a t e d because i t was found i n salamanders, r a t h e r than t u r t l e s , and because i t d i f f e r e d i n the a n t e r i o r e x t e n t of the v i t e l l i n e f o l l i c l e s , d i s t a n c e of the ovary from the c i r r u s s a c , and i n egg s i z e ( W a i t z , 1960). W a t e r t o r (1967) found t h a t 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 21 h i g h l y v a r i a b l e , and t h a t T. b o n n e r e n s i s w i l l mature i n t u r t l e s . She c o n c l u d e d t h a t the c h a r a c t e r i s t i c s o f T. c o r t i o v e r l a p p e d t h e measurements of T. b o n n e r e n s i s d e v e l o p i n g i n the same h o s t s , i n a l l c r i t e r i a h e r e t o f o r e employed t o d i f f e r e n t i a t e t h e s e two s p e c i e s , but d i d not propose a synonymy. My study c o n f i r m s W a t e r t o r ' s c o n c l u s i o n s . I t h e r e f o r e d e s i g n a t e T. b o n n e r e n s i s a j u n i o r s u b j e c t i v e synonym of T. c o r t i . T e l o r c h i s a u r i d i s t o m i B y r d , 1937 [ f i g u r e 10] SYNONYMS: C e r c o r c h i s a u r i d i s t o m i B y r d , 1937. HOSTS: F a r a n c i a abacura H o l b r o o k , 1836, the r e d - b e l l i e d mud snake. LOCALITIES: Payne's P r a i r i e , v i c i n i t y of G a i n e s v i l l e , F l o r i d a . SPECIMENS MEASURED: 5, HWML No. 20896. TAXONOMIC CHARACTERISTICS: Body e l o n g a t e , 2.1-2.5 mm l o n g ; r a t i o of l e n g t h t o w i d t h 8-10.7:1 (X=9:1). O r a l s u c k e r w i t h a n t e r o l a t e r a l l a p p e t s ; 227-247 i n d i a m e t e r . Pharynx 67-78 i n d i a m e t e r ; r a t i o of o r a l s u c k e r w i d t h t o pharynx w i d t h 1:0.29-0.32 (x=1:0.30). Esophagus 43-47 l o n g , 2% TBL. C e c a l b i f u r c a t i o n 11-17% TBL from a n t e r i o r end; c e c a e x t e n d w e l l p a s t t e s t e s , 0.7-1.5% TBL from p o s t e r i o r end. Acetabulum 122-129 i n d i a m e t e r . Forebody 22-27% TBL. R a t i o of o r a l s u c ker w i d t h t o a c e t a b u l a r w i d t h 1:0.5-0.57 (x=1:0.53). T e s t e s s p h e r i c a l t o o v o i d , tandem, c o n t i g u o u s , i n t e r c e c a l ; p o s t t e s t i c u l a r space 3-5% TBL. C i r r u s sac ends partway down t o j u s t p o s t e r i o r t o o v a r y . G e n i t a l pore v e n t r a l , p r e a c e t a b u l a r , 22 s l i g h t l y l e f t of median. Ovary 37-43% TBL from a n t e r i o r end, i n t e r c e c a l , s p h e r i c a l t o o v o i d . Seminal r e c e p t a c l e s m a l l ; L a u r e r ' s c a n a l not ob s e r v e d ; M e h l i s ' g l a n d p r e s e n t . Space o c c u p i e d by u t e r u s 48-51% TBL; metraterm 2/3 l e n g t h of c i r r u s s a c . V i t e l l i n e f o l l i c l e s c o n t i n u o u s l a t e r a l bands; ex t e n d a n t e r i o r l y from j u s t a n t e r i o r t o . j u s t p o s t e r i o r t o o v a r y , p o s t e r i o r l y from j u s t a n t e r i o r t o partway down t e s t e s . Eggs 33-36 l o n g by 15 wide. A n t e r i o r e x t e n t of e x c r e t o r y v e s i c l e a t o v a r i a n l e v e l . REMARKS: The specimens from which 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 were c o l l e c t e d from F a r a n c i a abacura H o l b r o o k , 1836 a t Harvey, L o u i s i a n a . S t u n k a r d and Franz (1977) e r e c t e d a new genus, P a r a t e l o r c h i s , t o accommodate T. a u r i d i s t o m i . They j u s t i f i e d t h i s d e c i s i o n on the b a s i s of the a n t e r o l a t e r a l l a p p e t s on the o r a l s u c k e r , and v i t e l l i n e f o l l i c l e s t h a t o v e r l a p the c e c a . S i n c e the v i t e l l i n e f o l l i c l e s of o t h e r t e l o r c h i i d s o v e r l a p the c e c a , and the o r a l l a p p e t s a r e c o n s i d e r e d an autapomorphy f o r the s p e c i e s , a s e p a r a t e genus i s c o n s i d e r e d t o be un n e c e s s a r y . T e l o r c h i s angustus S t a f f o r d , 1905 [ f i g u r e 11] SYNONYMS: Distomum angustum S t a f f o r d , 1900; T e l o r c h i s ( P r o t e n e s ) angustus B a r k e r and Covey, 1911; T e l o r c h i s ( P r o t e n e s ) l e p t u s B a r k e r and Covey, 1911; P r o t e n e s angustus S t u n k a r d , 1915; P r o t e n e s chapmani Harwood, 1932; P r o t e n e s v i t e l l o s u s B e n n e t t , 1935. 23 HOSTS: Chrysemys p i c t a S c h n e i d e r , 1837, p a i n t e d t u r t l e ; Chrysemys s c r i p t a e l e g a n s Wied, 1839, r e d - e a r e d t u r t l e ; Chrysemys p i c t a m a r g i n a t a A g a s s i z , 1857, m i d l a n d p a i n t e d t u r t l e . LOCALITIES: Rosenburg, Texas; "Ohio"; Baton Rouge, L a . ; Unknown (New York Aquarium). SPECIMENS MEASURED: 9, USNM Helm. C o l l . Nos. 7318, 30893, 36179, 51810, 73769. TAXONOMIC CHARACTERISTICS: Body e l o n g a t e , 3.1-4.5 mm l o n g ; r a t i o of l e n g t h t o w i d t h 6-9.6:1 (X=7.6:1). O r a l sucker 105-176 i n d i a m e t e r . Pharynx 61-96 i n d i a m e t e r ; r a t i o of o r a l s u c k e r w i d t h t o pharynx w i d t h 1:0.5-0.75 (x=1:0.63). Esophagus 121-242 l o n g , 4-6% TBL. C e c a l b i f u r c a t i o n 11-14% TBL from a n t e r i o r end; ceca e x t e n d w e l l p a s t t e s t e s , 1-6% TBL from p o s t e r i o r end. Acetabulum 61-165 i n d i a m e t e r . Forebody 22-25% TBL. R a t i o of o r a l s u c k e r w i d t h t o a c e t a b u l a r w i d t h 1:0.58-0.94 (x=1:0.73). T e s t e s s p h e r i c a l t o e l l i p t i c a l , tandem, c o n t i g u o u s , i n t e r c e c a l ; p o s t t e s t i c u l a r space 7-13% TBL. C i r r u s sac ends j u s t a n t e r i o r t o j u s t p o s t e r i o r t o acetabulum. G e n i t a l pore d o r s a l , l a t e r a l t o l e f t cecum, j u s t p o s t e r i o r t o c e c a l b i f u r c a t i o n . Ovary 31-38% TBL from a n t e r i o r end, i n t e r c e c a l , s p h e r i c a l t o o v o i d . Seminal r e c e p t a c l e s m a l l ; L a u r e r ' s c a n a l not o b s e r v e d ; M e h l i s ' g l a n d p r e s e n t . Space o c c u p i e d by u t e r u s 62-66% TBL; metraterm 1/2 t o 3/4 l e n g t h c i r r u s s a c . V i t e l l i n e f o l l i c l e s c o n t i n u o u s l a t e r a l bands; e x t e n d a n t e r i o r l y midway between acetabulum and ovary t o j u s t p o s t e r i o r t o o v a r y , p o s t e r i o r l y 3/4 d i s t a n c e acetabulum t o ovary t o partway down 24 t e s t e s . Eggs 31-41 l o n g by 16-24 wide. A n t e r i o r e x t e n t of e x c r e t o r y v e s i c l e 1/2 t o 2/3 acetabulum t o o v a r y . REMARKS: T h i s s p e c i e s has a l s o been r e p o r t e d from Chrysemys  m a r g i n a t a a t S t . P e t e r , M i n n e s o t a ( B a r k e r and Covey, 1911) and Chrysemys p i c t a from A t k i n s o n Lake, Nebraska (Brooks'and Mayes, 1976). The f o u r p u t a t i v e s p e c i e s of P r o t e n e s have been d i f f e r e n t i a t e d on the b a s i s of the ovary p o s i t i o n , p resence or absence of a L a u r e r ' s c a n a l , s i z e , l e n g t h of c i r r u s s a c , and e x t e n t of v i t e l l i n e f o l l i c l e s . The presence or absence of a L a u r e r ' s c a n a l i s not a r e l i a b l e c h a r a c t e r i s t i c , as i t i s e x t r e m e l y d i f f i c u l t t o l o c a t e . The o t h e r c h a r a c t e r i s t i c s a r e known t o v a r y i n t r a s p e c i f i c a l l y . Wharton (1940) c o n c l u d e d t h a t t h e r e was p r o b a b l y o n l y one v a l i d s p e c i e s . The p r e s e n t a n a l y s i s s u p p o r t s t h i s c o n c l u s i o n . B a r k e r and Covey (1911) e r e c t e d the genus P r o t e n e s t o accommodate t e l o r c h i i d s p o s s e s s i n g a g e n i t a l pore t h a t i s d o r s o l a t e r a l t o the l e f t cecum, and a c i r r u s sac t h a t extends o n l y t o the a c e t a b u l a r l e v e l . S i n c e t h e r e i s o n l y one s p e c i e s , and t h e s e two unique t r a i t s can be c o n s i d e r e d autapomorphies f o r the s p e c i e s , p l a c i n g t h i s s p e c i e s i n i t s own genus seems s u p e r f l u o u s . T e l o r c h i s scabrae Macdonald and B rooks, i n p r e s s [ f i g u r e 12] HOST: Chrysemys s c r i p t a s c r i p t a S c h o e p f f , 1792, y e l l o w - b e l l i e d 25 t u r t l e . LOCALITY: Unknown (New York Aquarium). SPECIMENS MEASURED: 7, USNM Helm. C o l l . No. 36175. TAXONOMIC CHARACTERISTICS: Body e l o n g a t e , 4.8-5.6 mm l o n g ; r a t i o of l e n g t h t o w i d t h 5.6-7.2:1 (X=6.5:1). O r a l sucker 124-154 i n d i a m e t e r . Pharynx 66-77 i n d i a m e t e r ; r a t i o of o r a l s u c k e r w i d t h to pharynx w i d t h (1:0.46-0.55 (x=1:0.49). Esophagus 72-88 l o n g , 2% TBL. C e c a l b i f u r c a t i o n 6-7% TBL from a n t e r i o r end; ceca extend w e l l p a s t t e s t e s , 3-5% TBL from p o s t e r i o r end. Acetabulum 121-150 i n d i a m e t e r . Forebody 11-14% TBL. R a t i o of o r a l s u c k e r w i d t h t o a c e t a b u l a r w i d t h 1:0.85-0.97 (x=1:0.95). T e s t e s s p h e r i c a l t o s u b c i r c u l a r , tandem, not c o n t i g u o u s , i n t e r c e c a l ; p o s t t e s t i c u l a r space 6-9% TBL. C i r r u s sac 578-825 l o n g , e x t r e m e l y r o b u s t and mu s c u l a r ; e x t e n d i n g p o s t e r i o r l y about 2/3 d i s t a n c e from acetabulum t o o v a r y ; c o n t a i n i n g s l i g h t l y c o i l e d s e m i n a l v e s i c l e , e l o n g a t e p r o s t a t i c complex and e v e r s i b l e c i r r u s . G e n i t a l pore v e n t r a l t o l e f t cecum, e q u a l or a n t e r o l a t e r a l t o acetabulum. Ovary 31-36% TBL from a n t e r i o r end, ' i n t e r c e c a l , o v o i d t o e l l i p t i c a l . S eminal r e c e p t a c l e s m a l l ; L a u r e r ' s c a n a l not obs e r v e d ; M e h l i s ' g l a n d p r e s e n t . Descending and a s c e n d i n g l o o p s of u t e r u s c o n f i n e d t o a r e a between ov a r y and t e s t e s ; space o c c u p i e d by u t e r u s 45-48% TBL; metraterm e q u a l t o 1/2 l e n g t h of c i r r u s s a c . V i t e l l i n e f o l l i c l e s c o n t i n u o u s l a t e r a l bands; ext e n d from 2/3 t o 4/5 ovary t o t e s t e s t o midway between acetabulum and o v a r y . Eggs 30-31 l o n g by 14-17 wide. A n t e r i o r e x t e n t of e x c r e t o r y v e s i c l e not ob s e r v e d ; 26 e x c r e t o r y pore t e r m i n a l . REMARKS: MacCallum (1919) gave t h e s e specimens a l a b e l name, but never f o r m a l l y d e s c r i b e d them. T h i s s p e c i e s most c l o s e l y resembles T. c h e l o p i by p o s s e s s i n g a r o b u s t , muscular c i r r u s s a c , but l a c k s the prominent p h a r y n g e a l g l a n d s and t h i c k e n e d c e c a l e p i t h e l i a l l i n i n g of t h a t s p e c i e s . I t can be d i s t i n g u i s h e d from a 1.1 o t h e r t e l o r c h i i d s by the p o s i t i o n of the g e n i t a l p o r e , which i s v e n t r a l t o the l e f t cecum. No o t h e r specimens of T e l o r c h i s s c a b r a e have ever been r e p o r t e d . The h o s t o c c u r s from s o u t h e a s t e r n V i r g i n i a t o n o r t h e r n F l o r i d a (Conant, 1975), so t h i s s p e c i e s of T e l o r c h i s p r o b a b l y o c c u r s t h e r e . T e l o r c h i s c h e l o p i MacCallum, 1919 [ f i g u r e 13] SYNONYMS: T e l o r c h i s g u t t u r o s i Brooks and Mayes, 1976, new  synonym. HOSTS: Clemmys i n s c u l p t a Le Conte, 1830, wood t u r t l e ; Chrysemys  s c r i p t a s c r i p t a S c h o e p f f , 1792, y e l l o w - b e l l i e d t u r t l e ; Chrysemys  p i c t a S c h n e i d e r , 1873, p a i n t e d t u r t l e . LOCALITY: Unknown (New Yor k . A q u a r i u m ) . SPECIMENS MEASURED: 29, USNM Helm. C o l l . Nos. 25265, 35265, 36174, 36176, 73522, 73523; HWML #20231. TAXONOMIC CHARACTERISTICS: Body e l o n g a t e , 4.8-7.1 mm l o n g ; r a t i o of l e n g t h t o w i d t h 4.6-8.8:1 ( X = 5 . 7 : 1 ) . O r a l s u c k e r 209-314 i n d i a m e t e r . Pharynx w i t h prominent p h a r y n g e a l g l a n d s , 94-209 i n d i a m e t e r ; r a t i o of o r a l s u c ker w i d t h t o pharynx w i d t h 1:0.41-27 0.75 (x=1:0.59). Esophagus 11-116 l o n g , 0.7-2.6% TBL. C e c a l b i f u r c a t i o n 8-16% TBL from a n t e r i o r end; ceca e x t e n d w e l l p a s t t e s t e s , 1.5-6% TBL from p o s t e r i o r end; c e c a l e p i t h e l i u m t h i c k e n e d a t b i f u r c a t i o n . Acetabulum 132-220 i n d i a m e t e r . Forebody 15-29% TBL. R a t i o of o r a l s u c k er w i d t h t o a c e t a b u l a r w i d t h 1:0.55-0.9 (x=1:0.73). T e s t e s s p h e r i c a l t o e l l i p t i c a l , tandem, c o n t i g u o u s , i n t e r c e c a l ; p o s t t e s t i c u l a r space 7-16% TBL. c i r r u s sac e x t r e m e l y r o b u s t and m u s c u l a r ; ends partway down t o j u s t p o s t e r i o r t o o v a r y . G e n i t a l pore v e n t r a l , p r e a c e t a b u l a r , i n t e r c e c a l ; median or s l i g h t l y l e f t of median. Ovary 26-41% TBL from a n t e r i o r end, i n t e r c e c a l , s p h e r i c a l t o o v o i d . S eminal r e c e p t a c l e and L a u r e r ' s c a n a l not o b s e r v e d ; M e h l i s ' g l a n d p r e s e n t . Space o c c u p i e d by u t e r u s 44-52% TBL; metraterm 2/3 l e n g t h of c i r r u s s a c . V i t e l l i n e f o l l i c l e s c o n t i n u o u s l a t e r a l bands; e x t e n d a n t e r i o r l y from p o s t e r i o r of ovary t o j u s t a n t e r i o r t o o v a r y , p o s t e r i o r l y 4/5 d i s t a n c e from ovary t o t e s t e s t o partway down a n t e r i o r t e s t i s . Eggs 32-40 l o n g by 12-20 wide. A n t e r i o r e x t e n t of e x c r e t o r y v e s i c l e from o v a r i a n l e v e l t o between acetabulum and o v a r y . REMARKS: Wharton (1940) synonymized T e l o r c h i s c h e l o p i w i t h T. c o r t i . However, not o n l y i s T. c h e l o p i c o n s i d e r a b l y l a r g e r , i t p o s s e s s e s two autapomorphies, prominent p h a r y n g e a l g l a n d s and a t h i c k e n e d e p i t h e l i u m , t h a t a r e q u i t e d i s t i n c t i v e . I t a l s o p o s s e s s e s a r o b u s t , muscular c i r r u s s a c , which T. c o r t i does n o t . 28 Brooks and Mayes (1976) d e s c r i b e d T. g u t t u r o s i from Graptemys pseudogeographica c o l l e c t e d a t A t k i n s o n Lake i n Nebraska. Type specimens of T. g u t t u r o s i appear t o be l e s s than f u l l y mature T. c h e l o p i . T e l o r c h i s r o b u s t u s G o l d b e r g e r , 1911 [ f i g u r e 14] SYNONYMS: C e r c o r c h i s r o b u s t u s G o l d b e r g e r , 1911. HOSTS: Terrapene C a r o l i n a L i n n e , 1758, box t u r t l e . LOCALITIES: G r e a t F a l l s , Md.; Wood's H o l e , Mass.; P i s c a t a w a , Md.; Mount Vernon, Va.; " L o u i s i a n a " . SPECIMENS MEASURED: 22, USNM Helm. C o l l . Nos. 28300, 32411, 36180, 40204, 43402, 71429. TAXONOMIC CHARACTERISTICS: Body e l o n g a t e , 6.6-15.1 mm l o n g ; r a t i o of l e n g t h t o w i d t h 5.1-9.5:1 ( X = 7 . 6 : 1 ) . O r a l s u c k e r 209-407 i n d i a m e t e r . Pharynx 110-209 i n d i a m e t e r ; r a t i o of o r a l s u c k e r w i d t h t o pharynx w i d t h 1:0.44-0.70 (x=1:0.55). Esophagus a b s e n t . C e c a l b i f u r c a t i o n 3-6% TBL from a n t e r i o r end; ce c a e x t e n d w e l l p a s t t e s t e s , 0.7-2% TBL from p o s t e r i o r end. Acetabulum 132-319 i n d i a m e t e r . Forebody 14-32% TBL. R a t i o of o r a l s u c ker w i d t h t o a c e t a b u l a r w i d t h 1:0.63-0.91 (x=1:0.79). T e s t e s s p h e r i c a l t o e l l i p t i c a l , tandem, not c o n t i g u o u s , i n t e r c e c a l ; p o s t t e s t i c u l a r space 3-7% TBL. C i r r u s sac ends j u s t a n t e r i o r t o partway down o v a r y . G e n i t a l pore v e n t r a l , p r e a c e t a b u l a r , i n t e r c e c a l , s l i g h t l y l e f t of median. Ovary 45-58% TBL from a n t e r i o r end, i n t e r c e c a l , s p h e r i c a l t o e l l i p t i c a l . S eminal r e c e p t a c l e s m a l l ; L a u r e r ' s c a n a l not 29 o b s e r v e d ; M e h l i s ' g l a n d p r e s e n t . Space o c c u p i e d by u t e r u s 43-56% TBL; metraterm 1/2 t o 2/3 l e n g t h of c i r r u s s a c . V i t e l l i n e f o l l i c l e s c o n t i n u o u s l a t e r a l bands; ex t e n d a n t e r i o r l y from j u s t a n t e r i o r t o acetabulum t o 4/5 d i s t a n c e acetabulum t o ov a r y , p o s t e r i o r l y from midway between ovary and t e s t e s t o j u s t a n t e r i o r t o t e s t e s . Eggs 24-30 l o n g by 11-16 wide. A n t e r i o r e x t e n t of e x c r e t o r y v e s i c l e a t a c e t a b u l a r l e v e l . REMARKS: Bennett and Sharp (1938) r e p o r t e d t h i s s p e c i e s from S t e r n o t h e r u s o d o r a t u s i n L o u i s i a n a . I t was a l s o r e p o r t e d by Brooks (1979b) from S t e r n o t h e r u s c a r i n a t u s Gray, 1856 a t R i c h l a n d P a r i s h , L o u i s i a n a . T e l o r c h i s s i n g u l a r i s B e n n e t t , 1935 [ f i g u r e 15] SYNONYMS: C e r c o r c h i s s i n g u l a r i s B e n n e t t , 1935. HOSTS: Chrysemys s c r i p t a e l e g a n s Wied, 1839, r e d - e a r e d t u r t l e ; Chrysemys s c r i p t a s c r i p t a S c h o e p f f , 1792, y e l l o w - b e l l i e d t u r t l e . LOCALITIES: Baton Rouge, L a . ; Lake Conway, A r k a n s a s . SPECIMENS MEASURED: 3, USNM Helm. C o l l . Nos. 51489, 74843. TAXONOMIC CHARACTERISTICS: Body f i l i f o r m , 8.7-9.8 mm l o n g ; r a t i o of l e n g t h t o w i d t h 8.7-9.8:1 ( X = 7 . 8 : 1 ) . O r a l s u c k e r 154-220 i n d i a m e t e r . Pharynx 110-143 i n d i a m e t e r ; r a t i o of o r a l sucker w i d t h t o pharynx w i d t h 1:0.65-0.86 (x=1:0.74). Esophagus 77 l o n g , 1% TBL. C e c a l b i f u r c a t i o n 6% TBL from a n t e r i o r end; ceca e x t e n d w e l l p a s t t e s t e s , 1% TBL from p o s t e r i o r end. Acetabulum 143-198 i n d i a m e t e r . Forebody 18-28% TBL. R a t i o of o r a l sucker w i d t h t o a c e t a b u l a r w i d t h 1:0.9-0.93 (X = 1 : 0 . 9 1 ) . 30 T e s t e s o v o i d t o e l l i p t i c a l , tandem, not c o n t i g u o u s , i n t e r c e c a l ; p o s t t e s t i c u l a r space 2-5% TBL. C i r r u s sac ends j u s t a n t e r i o r t o partway down ov a r y . G e n i t a l pore v e n t r a l , p r e a c e t a b u l a r , i n t e r c e c a l , median or s l i g h t l y l e f t of median. Common g e n i t a l a t r i u m p r e s e n t . Ovary 57-59% TBL from a n t e r i o r end, i n t e r c e c a l , s p h e r i c a l t o e l l i p t i c a l . Seminal r e c e p t a c l e and L a u r e r ' s c a n a l not obs e r v e d ; M e h l i s ' g l a n d p r e s e n t . Space o c c u p i e d by u t e r u s 43-48% TBL; metraterm 1/2 l e n g t h of c i r r u s s a c ; p o s s e s s i n g a muscular b u l b . V i t e l l i n e f o l l i c l e s c o n t i n u o u s l a t e r a l bands; ext e n d a n t e r i o r l y 1/3 t o 1/2 d i s t a n c e acetabulum t o o v a r y , p o s t e r i o r l y j u s t a n t e r i o r t o partway down t e s t e s . Eggs 24 l o n g by 16 wide. A n t e r i o r e x t e n t of e x c r e t o r y v e s i c l e t o M e h l i s ' g l a n d . T e l o r c h i s a t t e n u a t u s G o l d b e r g e r , 1911 [ f i g u r e 16] SYNONYMS: C e r c o r c h i s a t t e n u a t u s G o l d b e r g e r , 1911. HOSTS: Chrysemys p i c t a S c h n e i d e r , 1873, p a i n t e d t u r t l e . LOCALITIES: Lake Maxinkuckee, I n d i a n a ; A t k i n s o n Lake, Nebraska. SPECIMENS MEASURED: 7, USNM Helm. C o l l . No. 10523; D.R. Brooks' p e r s o n a l c o l l e c t i o n . TAXONOMIC CHARACTERISTICS: Body f i l i f o r m , 10.2-11.6 mm l o n g ; r a t i o of l e n g t h t o w i d t h 11.4-17.2:1 (X=15.8:1). O r a l s u c k e r 143-185 i n d i a m e t e r . Pharynx 88-102 i n d i a m e t e r ; r a t i o of o r a l s u c k er w i d t h t o pharynx w i d t h 1:0.49-0.62 (x=1:0.56). Esophagus 90-123 l o n g , 0.8-1.2% TBL. C e c a l b i f u r c a t i o n 4% TBL from 31 a n t e r i o r end; c e c a e x t e n d w e l l p a s t t e s t e s , 0.34-1.4% TBL from p o s t e r i o r end. Acetabulum 118-165 i n d i a m e t e r . Forebody 14-19% TBL. R a t i o of o r a l s u c k e r w i d t h t o a c e t a b u l a r w i d t h 1:0.66-0.88 (x=1:0.75). T e s t e s s p h e r i c a l t o o v o i d , tandem, not c o n t i g u o u s , i n t e r c e c a l ; p o s t t e s t i c u l a r space 3-5% TBL. C i r r u s sac ends 1/2 t o 2/3 d i s t a n c e acetabulum t o o v a r y . G e n i t a l pore v e n t r a l , p r e a c e t a b u l a r , i n t e r c e c a l , s l i g h t l y l e f t of median. Ovary 50-55% TBL from a n t e r i o r end, i n t e r c e c a l , s p h e r i c a l t o o v o i d . Seminal r e c e p t a c l e p r e s e n t ; L a u r e r ' s c a n a l not o b s e r v e d ; M e h l i s ' g l a n d p r e s e n t . Space o c c u p i e d by u t e r u s 63-66% TBL; metraterm 2/5 t o 1/2 l e n g t h of c i r r u s s a c . V i t e l l i n e f o l l i c l e s c o n t i n u o u s l a t e r a l bands; e x t e n d a n t e r i o r l y 1/3 t o 4/5 d i s t a n c e acetabulum t o o v a r y , p o s t e r i o r l y 3/4 t o 5/6 d i s t a n c e o v a r y t o t e s t e s . A n t e r i o r e x t e n t of e x c r e t o r y v e s i c l e t o 1/3 d i s t a n c e acetabulum t o o v a r y . SPECIES INQUIRENDA T e l o r c h i s compactus C a b l e and Sanborn , 1970 [ f i g u r e 17], d e s c r i b e d from Emydoidea b l a n d i n g i , i s of u n c e r t a i n s t a t u s a t t h i s t i m e . F i v e m o r p h o l o g i c a l f e a t u r e s t h a t a r e p a r t i a l l y d i a g n o s t i c of the genus T e l o r c h i s a r e the u t e r i n e c o n f i g u r a t i o n , the shape of the o v a r y , the p o s i t i o n of the o v a r y r e l a t i v e t o the acetabulum, the shape of the t e s t e s , and the p o s i t i o n of the t e s t e s . T e l o r c h i s compactus does not conform t o the d i a g n o s i s of T e l o r c h i s i n any of these c h a r a c t e r t r a i t s ; f u r t h e r m o r e , i t 32 d i f f e r s by l i v i n g i n the o v i d u c t s r a t h e r than the i n t e s t i n e of the t u r t l e h o s t . What needs t o be d e t e r m i n e d , t h e n , i s whether T. compactus c o u l d be an a b e r r a n t t e l o r c h i i d (as suggested by Ca b l e and Sanborn, 1970) , or i f i t b e l o n g s i n a s e p a r a t e genus. One way t o d e c i d e w i l l be t o l o o k f o r e v i d e n c e of r e l a t i o n s h i p from l i f e h i s t o r y s t u d i e s , which i s beyond the scope of t h i s s t u d y . KEY TO THE SPECIES OF TELORCHIS 1a. V i t e l l i n e f o l l i c l e s c l u s t e r e d i n groups; acetabulum l a r g e r than o r a l s u c k er 2 1b. V i t e l l i n e f o l l i c l e s i n c o n t i n u o u s l a t e r a l bands; acetabulum s m a l l e r than or e q u a l t o o r a l s u c k e r 3 2a. R a t i o of body l e n g t h t o body w i d t h l e s s than 4:1 T. s i r e n i s 2b. R a t i o of body l e n g t h t o body w i d t h g r e a t e r than 4:1 T. s t u n k a r d i 3a. Ovary c l o s e r t o acetabulum than t e s t e s ... 4 3b. Ovary c l o s e r t o t e s t e s than acetabulum 9 4a. O r a l s u c k e r l a c k i n g a n t e r o l a t e r a l l a p p e t s 5 4b. O r a l s u c k e r w i t h a n t e r o l a t e r a l l a p p e t s T. a u r i d i s t o m i 5a. G e n i t a l pore p r e a c e t a b u l a r , median or s l i g h t l y l e f t . . . . . 6 5b. G e n i t a l pore v e n t r a l or d o r s o l a t e r a l t o l e f t cecum 7 6a. O v i g e r o u s specimens 4.8 mm or more i n body l e n g t h 8 6b. O v i g e r o u s specimens 4.5 mm or l e s s i n body l e n g t h T. c o r t i 33 7a. G e n i t a l pore d o r s a l , l a t e r a l t o l e f t cecum.... T. angustus 7b. G e n i t a l pore v e n t r a l t o l e f t cecum T. scabrae 8a. Esophagus p r e s e n t T. c h e l o p i 8b. Esophagus l a c k i n g T. r o b u s t u s 9a. M e t r a t e r m w i t h muscular b u l b T. s i n g u l a r i s 9b. M e t r a t e r m l a c k i n g muscular b u l b T. a t t e n u a t u s PHYLOGENETIC ANALYSIS A p h y l o g e n e t i c a n a l y s i s based on 22 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 20 homologous s e r i e s produced a s i n g l e t r e e [ f i g u r e 18]. T h i s p h y l o g e n e t i c t r e e r e p r e s e n t s 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 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 among N o r t h American t e l o r c h i i d s . The c o n s i s t e n c y index (Kluge and F a r r i s , 1969), a goodness of f i t measure, i s 95%, i n d i c a t i n g a low l e v e l of p a r a l l e l and conv e r g e n t e v o l u t i o n among the c h a r a c t e r s used. There i s o n l y one homoplasious c h a r a c t e r i s t i c i n the a n a l y s i s , a p a r a l l e l i s m i n c h a r a c t e r s 12 and 13. The o c c u r r e n c e of T. an g u s t u s and T. a u r i d i s t o m i i n a polytomy w i t h T. c o r t i i s a f u r t h e r i n d i c a t i o n t h a t they a r e t e l o r c h i i d s , and s h o u l d t h e r e f o r e not be p l a c e d i n s e p a r a t e genera. I t i s d e s i r a b l e f o r the c l a s s i f i c a t i o n of a group t o 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 , or h i s t o r y of d e s c e n t , of t h a t group. The p h y l o g e n e t i c t r e e i n d i c a t e s t h a t these two s p e c i e s and the r e s t of the t e l o r c h i i d s e v o l v e d from a common a n c e s t o r . I f T. angustus and T. a u r i d i s t o m i a r e p l a c e d i n s e p a r a t e g e n e r a, the genus T e l o r c h i s w i l l be ren d e r e d p a r a p h y l e t i c , and thus not c o n t a i n a l l of the descendents of the 34 common t e l o r c h i i d a n c e s t o r . In orde r f o r the c l a s s i f i c a t i o n t o r e f l e c t t he phylogeny, the genera P r o t e n e s and P a r a t e l o r c h i s must not be used. DISCUSSION CLASSIFICATION The r e s u l t s of t h i s study support the placement of the N o r t h American t e l o r c h i i d s p e c i e s i n the s i n g l e genus T e l o r c h i s . C h a r a c t e r s p r e v i o u s l y used t o d i v i d e the group i n t o two s e p a r a t e genera, T e l o r c h i s and C e r c o r c h i s , have been shown t o e x h i b i t pronounced m o r p h o l o g i c a l v a r i a t i o n . S i n c e i n d i v i d u a l s from a s i n g l e s p e c i e s may p o s s e s s the " T e l o r c h i s " morphology f o r one c h a r a c t e r i s t i c , and the " C e r c o r c h i s " morphology f o r a n o t h e r , t h e r e i s no j u s t i f i c a t i o n f o r s e p a r a t e g e n e r a . There i s a l s o no su p p o r t f o r the monotypic genera P r o t e n e s , f o r P r o t e n e s a n g u s t u s , and P a r a t e l o r c h i s , f o r P a r a t e l o r c h i s  a u r i d i s t o m i . A l t h o u g h t h e s e s p e c i e s p o s s e s s c h a r a c t e r i s t i c s t h a t a r e d i s t i n c t i v e and u n i q u e , they also, p o s s e s s a l l of the c h a r a c t e r i s t i c s t h a t a r e d i a g n o s t i c of the genus T e l o r c h i s . T h e i r p o s s e s s i o n of autapomorphies does not r e q u i r e them t o be p l a c e d i n a s e p a r a t e genus. F u r t h e r m o r e , t h e i r placement i n the middle of the p h y l o g e n e t i c t r e e s u p p o r t s t h e i r membership i n T e l o r c h i s . I f they a r e g i v e n g e n e r i c s t a t u s , T e l o r c h i s would have t o be broken down i n t o many s m a l l genera. 35 EVOLUTIONARY HISTORY There a r e t h r e e main a s p e c t s of the e v o l u t i o n a r y h i s t o r y of p a r a s i t e s t h a t can be examined once a p h y l o g e n e t i c study has been done. These q u e s t i o n s a r e : (a) "Where do the p a r a s i t e s o c c u r ? " , which i s a study of the biogeography of the organisms; (b) " I n what h o s t s a r e they found?", which examines h o s t -p a r a s i t e r e l a t i o n s h i p s and c o e v o l u t i o n ; and (c) "What f u n c t i o n a l and/or s t r u c t u r a l a t t r i b u t e s a r e r e l e v a n t t o the h o s t - p a r a s i t e r e l a t i o n s h i p ? " , which may h e l p t o e x p l a i n unique or u n u s u a l r e l a t i o n s h i p s . A. BIOGEOGRAPHY The b i o l o g i c a l h i s t o r y of organisms and the g e o l o g i c a l h i s t o r y of the a r e a s i n which they occur can be examined f o r congruence i n t h e i r e v o l u t i o n a r y t r e e s . T h i s t y p e of a n a l y s i s , c a l l e d v i c a r i a n c e biogeography (see C r o i z a t e_t a _ l . , 1974; N e l s o n and P l a t n i c k , 1981; C r a c r a f t , 1983), has been u t i l i z e d f o r a number of h e l m i n t h groups (see B r o o k s , 1985a f o r a r e v i e w ; a l s o Bandoni and B r o o k s , i n p r e s s ) . A b i o g e o g r a p h i c a n a l y s i s of T e l o r c h i s i s not f e a s i b l e a t t h i s t i m e . Incomplete c o l l e c t i n g and a l a c k of voucher specimens make t h i s type of a n a l y s i s d i f f i c u l t . For example, a map of c o n f i r m e d l o c a l i t i e s f o r T. c o r t i i s shown i n f i g u r e 19. A l l r e p o r t e d l o c a l i t i e s , many of which cannot be c o n f i r m e d , are shown i n f i g u r e 20. In a d d i t i o n , about h a l f of the specimens examined were taken from t u r t l e s a t the New York Aquarium; the 36 e x a c t l o c a l i t i e s f o r t h e s e specimens a r e unknown. U n t i l more e x t e n s i v e , c a r e f u l l y documented c o l l e c t i n g i s c a r r i e d o u t , t h e r e i s not enough i n f o r m a t i o n t o conduct v i c a r i a n c e s t u d i e s . B. HOST-PARASITE RELATIONSHIPS U s i n g p h y l o g e n e t i c s y s t e m a t i c s , i t i s p o s s i b l e t o d etermine the degree t o which contemporaneous h o s t - p a r a s i t e r e l a t i o n s h i p s r e f l e c t l o n g - s t a n d i n g a s s o c i a t i o n s between the h o s t group and the p a r a s i t e group. T h i s methodology has been employed f o r a number of c o e v o l u t i o n s t u d i e s ( f o r a r e v i e w see B r o o k s , 1985a). The term c o e v o l u t i o n encompasses two phenomena, co-s p e c i a t i o n and co-accommodation. C o - s p e c i a t i o n r e f e r s t o the e x i s t e n c e of congruence between ho s t and p a r a s i t e p h y l o g e n i e s as a r e s u l t of c o n c o m i t a n t s p e c i a t i o n ( B r o o k s , 1979a). T h i s i m p l i e s t h a t c l a d o g e n e s i s of the p a r a s i t e s p e c i e s o c c u r r e d as a r e s u l t o f , or c o n c o m i t a n t w i t h , h o s t c l a d o g e n e s i s . What you would expect t o f i n d , t h e n , i f c o - s p e c i a t i o n p l a y s a major r o l e i n t h e s e r e l a t i o n s h i p s , i s congruence between h o s t phylogeny and p a r a s i t e p h y logeny. Co-accommodation r e f e r s t o the r e l a t i o n s h i p between a p a r a s i t e s p e c i e s and i t s h o s t d u r i n g the p e r i o d i n which the p a r a s i t e e x h i b i t s no c l a d o g e n e s i s ( B r o o k s , 1979a). Both c o - s p e c i a t i o n and co-accommodation w i l l be a d d r e s s e d w i t h r e p s e c t t o T e l o r c h i s phylogeny. A p a r a s i t e may occur i n a p a r t i c u l a r h o s t as a r e s u l t of one of two p r o c e s s e s : c o l o n i z a t i o n , which would i n d i c a t e a r e c e n t a s s o c i a t i o n , or c o e v o l u t i o n , which i s i n d i c a t i v e of an a n c i e n t a s s o c i a t i o n ( B r o o k s , 1980). In c o l o n i z a t i o n , or h o s t -37 s w i t c h i n g , a s s o c i a t i o n s a r i s e by chance. Such a p a t t e r n i s i n c o n s i s t e n t w i t h the non-random a s s o c i a t i o n s t h a t a r e g e n e r a l l y o b s e r v e d ( B r o o k s , 1981). T h i s i s not t o say t h a t c o l o n i z a t i o n does not o c c u r ; i n d e e d , many contemporaneous h o s t - p a r a s i t e a s s o c i a t i o n s can o n l y be e x p l a i n e d i n terms of a h o s t - s w i t c h . A l s o , any i n s t a n c e of h o s t - p a r a s i t e c o e v o l u t i o n must have begun w i t h a c o l o n i z a t i o n of the h o s t ' s a n c e s t o r by the p a r a s i t e ' s a n c e s t o r . N e v e r t h e l e s s , the congruence between host and p a r a s i t e p h y l o g e n i e s p r o v i d e s e v i d e n c e t h a t h o s t s and t h e i r p a r a s i t e s have e v o l v e d t o g e t h e r ( B r o o k s , 1979a, 1980, 1981). The two most p l e s i o m o r p h i c N o r t h American t e l o r c h i i d s p e c i e s a r e T e l o r c h i s s i r e n i s and T. s t u n k a r d i . These s p e c i e s u s u a l l y u t i l i z e salamanders r a t h e r than t u r t l e s as h o s t s , a l t h o u g h T. s t u n k a r d i has been r e p o r t e d from t u r t l e s . Even though t e l o r c h i i d s are g e n e r a l l y c o n s i d e r e d t o be t u r t l e p a r a s i t e s , the o c c u r r e n c e of the most p l e s i o m o r p h i c s p e c i e s i n amphibians i s not i n c o n s i s t e n t w i t h a c o e v o l u t i o n a r y h y p o t h e s i s . A p a r t i a l p h y l o g e n e t i c t r e e of N o r t h American f r e s h w a t e r t u r t l e s , i n c l u d i n g o n l y t h o s e t a x a from which t e l o r c h i i d s have been r e p o r t e d , i s shown i n f i g u r e 21. When the p a r a s i t e s p e c i e s a r e mapped onto t h i s host p h y l o g e n y , f i v e of t h e e i g h t s p e c i e s found i n amniotes show p h y l o g e n e t i c congruence [ f i g u r e 2 2 ] , These s p e c i e s a r e c o n s i d e r e d t o have c o - s p e c i a t e d . The c o n s i s t e n c y index f o r the t r e e i n f i g u r e 22a i s o n l y 83% ( 5 / 6 ) . The reason t h a t the c o n s i s t e n c y index i s not 100%, as might be e x p e c t e d , i s t h a t T e l o r c h i s r o b u s t u s [C i n f i g u r e 22a] appears t o have e v o l v e d by c o - s p e c i a t i o n , and then 38 c o l o n i z e d a nother h o s t . A l t h o u g h T e l o r c h i s r o b u s t u s i s u s u a l l y found i n Terrapene C a r o l i n a , i t has been r e p o r t e d from S t e r n o t h e r u s c a r i n a t u s ( B r o o k s , 1979b) and S. o d o r a t u s (Bennett and Sharp, 1938) [ I I i n f i g u r e 2 2 a ] ; t h e s e h o s t s a r e i n c o n s i s t e n t w i t h the c o - s p e c i a t i o n h y p o t h e s i s . However, c o n s i d e r i n g t h a t a l l t h r e e host s p e c i e s e x h i b i t h a b i t a t o v e r l a p , the most l i k e l y e x p l a n a t i o n f o r t h i s phenomenon i s t h a t T. r o b u s t u s c o e v o l v e d w i t h Terrapene C a r o l i n a , and has s i n c e c o l o n i z e d S t e r n o t h e r u s c a r i n a t u s and S. o d o r a t u s . The o t h e r t h r e e s p e c i e s a r e not congruent w i t h an h y p o t h e s i s of c o - s p e c i a t i o n [see f i g u r e 23']. One of these s p e c i e s , T. a u r i d i s t o m i , i s p o s t u l a t e d t o have a r i s e n v i a a h o s t - s w i t c h from t u r t l e s t o snakes. T. s c a b r a e and T. angustus a r e p o s t u l a t e d t o have e v o l v e d v i a s y m p a t r i c s p e c i a t i o n . The hypotheses of e v o l u t i o n f o r t h e s e s p e c i e s w i l l be d i s c u s s e d i n more d e t a i l l a t e r . Brooks (1979a) d e f i n e d co-accommodation as the r e l a t i o n s h i p between a p a r a s i t e s p e c i e s and i t s h o s t d u r i n g the p e r i o d i n which the p a r a s i t e l i n e a g e e x h i b i t s no c l a d o g e n e s i s . T h i s i n v o l v e s p r i m a r i l y the phenomenon of h o s t s p e c i f i c i t y . P r i c e (1980) and Rohde (1982) d i v i d e h o s t s p e c i f i c i t y i n t o two d i s t i n c t a r e a s , the h o s t range of a p a r a s i t e , and the s p e c i f i c i t y of a p a r a s i t e . Host range i s d e f i n e d as the number of h o s t s p e c i e s f o r a c e r t a i n p a r a s i t e s p e c i e s i r r e s p e c t i v e of the f r e q u e n c y or i n t e n s i t y of i n f e c t i o n (Rohde, 1982). Many p a r a s i t e s e x h i b i t r a t h e r g e n e r a l host r e q u i r e m e n t s , and may become e s t a b l i s h e d i n 39 a wide v a r i e t y of h o s t s w i t h o u t u n d e r g o i n g s p e c i a t i o n (broad co-accommodation or broad h o s t r a n g e ) . A l t e r n a t i v e l y , o t h e r p a r a s i t e s have v e r y s p e c i f i c h o s t r e q u i r e m e n t s , and can s u r v i v e o n l y i n the h o s t s w i t h which they have c o - s p e c i a t e d (narrow co-accommodation or narrow ho s t range) ( B r o o k s , 1979a). S p e c i f i c i t y i s d e f i n e d as the f r e q u e n c y w i t h which a p a r t i c u l a r h o s t s p e c i e s i s . i n f e c t e d (Rohde, 1982). Even p a r a s i t e s found i n many host s p e c i e s u s u a l l y i n f e c t one or a few s p e c i e s more h e a v i l y than o t h e r s . For example, even though T e l o r c h i s c o r t i has been r e p o r t e d from t u r t l e s , snakes, and salamanders, i t i s c o l l e c t e d most f r e q u e n t l y from, and i s c o n s i d e r e d t o be p r i m a r i l y a p a r a s i t e o f , t u r t l e s . There a r e t h r e e p r e d i c t i o n s t h a t can be made about the r e l a t i o n s h i p between hos t s p e c i f i c i t y and e v o l u t i o n a r y h i s t o r y . The t r a d i t i o n a l view p r e d i c t s t h a t as p r i m a r i l y c o e v o l v e d p a r a s i t e s become more h i g h l y d e r i v e d , t h e i r host s p e c i f i c i t y w i l l become more pronounced ( B r o o k s , 1979a, 1985b). When h o s t s p e c i f i c i t y i s s a i d t o be pronounced, s p e c i f i c i t y i n c r e a s e s as the h o s t range narrows. T h i s does not n e c e s s a r i l y mean t h a t h o s t range and s p e c i f i c i t y a r e always i n v e r s e l y p r o p o r t i o n a l [see f i g u r e 2 5 ] , a l t h o u g h t h i s does seem t o be the predominant o b s e r v a t i o n . There i s a l s o the p o s s i b i l i t y t h a t as p a r a s i t e s become more h i g h l y d e r i v e d , s p e c i f i c i t y becomes l e s s pronounced; t h i s p a r t i c u l a r s i t u a t i o n does not seem t o have ever been ob s e r v e d . The t h i r d p r e d i c t i o n i s t h a t host s p e c i f i c i t y has no c o r r e l a t i o n w i t h h i s t o r y . The p r e s e n t a n a l y s i s s u p p o r t s the t r a d i t i o n a l view of host 40 s p e c i f i c i t y ; as p r i m a r i l y c o e v o l v e d t e l o r c h i i d s become more h i g h l y d e r i v e d , h o s t s p e c i f i c i t y becomes more pronounced [see f i g u r e 2 6 ] . T e l o r c h i s c o r t i , which i s c o n s i d e r e d t o be the r e l a t i v e l y most p l e s i o m o r p h i c s p e c i e s among thos e i n h a b i t i n g a m n i o t e s , has the g r e a t e s t h o s t range. I t has been r e p o r t e d from 15 d i f f e r e n t h o s t s p e c i e s , i n c l u d i n g two s p e c i e s of salamander and one s p e c i e s of snake. T h i s p a r t i c u l a r s p e c i e s a l s o e x h i b i t s low s p e c i f i c i t y ; even though i t seems t o occur most f r e q u e n t l y i n t u r t l e h o s t s , t h e r e does not seem t o be one p a r t i c u l a r s p e c i e s of t u r t l e t h a t i s p r e f e r e n t i a l l y i n f e c t e d . E lsewhere on the t r e e , T e l o r c h i s a t t e n u a t u s , one of the r e l a t i v e l y most d e r i v e d s p e c i e s , e x h i b i t s the most pronounced h o s t s p e c i f i c i t y , o c c u r r i n g i n o n l y one h o s t s p e c i e s , Chrysemys  p i c t a . In t h i s c a s e , the h o s t range i s v e r y narrow and the s p e c i f i c i t y i s v e r y pronounced. The g e n e r a l t r e n d i n the t e l o r c h i i d s , t h e n , has been an i n c r e a s e i n s p e c i f i c i t y as the 9 p a r a s i t e s become more h i g h l y d e r i v e d , w i t h a subsequent d e c r e a s e i n host range. T. a u r i d i s t o m i , T. a n g u s t u s , and T. s c a b r a e , because they d i d not c o e v o l v e w i t h t h e i r h o s t s , do not f o l l o w t h i s p a t t e r n . C. FUNCTIONAL/STRUCTURAL ATTRIBUTES T e l o r c h i s a u r i d i s t o m i i s g e o g r a p h i c a l l y s y m p a t r i c w i t h o t h e r t e l o r c h i i d s , but i s not found i n any t u r t l e h o s t s ( i . e . i t i s a l l o h o s p i t a l i c w i t h o t h e r t e l o r c h i i d s ) . T h i s s p e c i e s has been c o l l e c t e d e x c l u s i v e l y from F a r a n c i a a b a c u r a , the mud snake, y e t i t i s c l o s e l y r e l a t e d t o t e l o r c h i i d s p e c i e s found i n 41 t u r t l e s . The presence of T. a u r i d i s t o m i i n a snake h o s t cannot be e x p l a i n e d i n ' terms of c o e v o l u t i o n . I t i s t h e r e f o r e p o s t u l a t e d t o have a r i s e n v i a a h o s t - s w i t c h from t u r t l e s t o snakes. The c l o s e s t r e l a t i v e s of T. a u r i d i s t o m i a r e T. c o r t i and T. a n g u s t u s . A l t h o u g h T. c o r t i i s p r e d o m i n a n t l y a t u r t l e p a r a s i t e , i t has been c o l l e c t e d i n Thamnophis s i r t a l i s , the common g a r t e r snake ( W a i t z , 1960). In a d d i t i o n , the g e o g r a p h i c a l ranges of F a r a n c i a a b a c u r a , Thamnophis s i r t a l i s , and some of the t u r t l e h o s t s o v e r l a p t o some e x t e n t (Conant, 1975). S i n c e the g e o g r a p h i c a l ranges of the v a r i o u s host s p e c i e s o v e r l a p t o some e x t e n t , they would most c e r t a i n l y come i n c o n t a c t w i t h one a n o t h e r . I t seems l i k e l y , t h e n , t h a t a t some time i n the p a s t , the a n c e s t o r of T. a u r i d i s t o m i was a b l e t o c o l o n i z e snakes from t u r t l e s , v i a a h o s t - s w i t c h . Whether or not t h i s a n c e s t o r i s T. c o r t i i s unknown. The contemporary morphology of T. a u r i d i s t o m i i s a r e s u l t of subsequent s p e c i a t i o n w i t h the c o l o n i z e d h o s t . Both T e l o r c h i s scabrae and T. angustus o c c u r i n h o s t s t h a t a r e a l s o i n h a b i t e d by t h e i r c l o s e s t r e l a t i v e s . T. sc a b r a e i s most c l o s e l y r e l a t e d t o T. c h e l o p i ; both a r e found i n Chrysemys  s c r i p t a s c r i p t a . T. angustus i s a s i s t e r s p e c i e s of T. c o r t i ; t h ese s p e c i e s have two common h o s t s , Chrysemys p i c t a and Chrysemys s c r i p t a e l e g a n s . P a r a s i t e s t h a t e x h i b i t t h i s type of r e l a t i o n s h i p a r e s a i d t o be s y n h o s p i t a l i c . When a host s p e c i e s i s i n f e c t e d by two or more s i s t e r -42 species of parasites, i t is possible that the co-occurrence of the parasite species i s the result of sympatric speciation from some ancestral species, unless all o p a t r y and vicariance can be shown (Brooks, 1979a). In t h i s case, the sister-species are sympatric and synhospitalic. This implies that the parasite has speciated but the host has not. The major difference between T. scabrae and T. angustus and their s i s t er-species i s t h e i r genital pore morphology. Hermaphroditic digeneans mate by aligning their genital pores and exchanging gametes. Most t e l o r c h i i d s possess a genital pore that i s preacetabular and median or s l i g h t l y l e f t of median. The genital pore of T. scabrae i s ventral to the l e f t cecum, while that of T. angustus i s dorsolateral to the l e f t cecum. These changes in genital pore position make i t d i f f i c u l t to a l i g n genital pores with other t e l o r c h i i d s and could lead to mechanical pre-mating i s o l a t i o n . Subsequently, T. scabrae and T. angustus could have evolved independently from their closest r e l a t i v e s while inhabiting the same host. CONCLUSIONS The hypothesis of the evolutionary history of the North American species of Telorchis i s summarized in figure 27. T. s i r e n i s and T. stunkardi, the two most r e l a t i v e l y plesiomorphic species, are found in salamanders. T. c o r t i , T. chelopi, T. robustus, T. s i n g u l a r i s , and T. attenuatus are believed to have co-speciated with North American freshwater chelonians. The more highly derived a species i s in t h i s group, the more 43 pronounced the host s p e c i f i c i t y . T. a u r i d i s t o m i i s p o s t u l a t e d to have e v o l v e d v i a sympatric s p e c i a t i o n due to a h o s t - s w i t c h from t u r t l e s to snakes. T. scabrae and T. angustus appear to be the r e s u l t of sympatric s p e c i a t i o n due to the e v o l u t i o n of autapomorphies causing mechanical pre-mating i s o l a t i o n . There i s a need f o r a d d i t i o n a l taxonomic and experimental s t u d i e s of t e l o r c h i i d s . F u r t h e r experimental work on host-induced v a r i a t i o n and h o s t - s p e c i f i c i t y would enhance the present a n a l y s i s . H y b r i d i z a t i o n experiments might p r o v i d e some a d d i t i o n a l i n f o r m a t i o n on the sympatric s p e c i e s . F i n a l l y , more thorough c o l l e c t i n g of North American and worldwide T e l o r c h i s s p e c i e s would supply the i n f o r m a t i o n on d i s t r i b u t i o n p a t t e r n s that would make v i c a r i a n c e s t u d i e s p o s s i b l e , thus p r o v i d i n g a f u r t h e r t e s t of the r e l a t i o n s h i p between t e l o r c h i i d s and t h e i r h o s t s . 44 REFERENCES CITED Ban d o n i , S.M.; Br o o k s , D.R. In p r e s s . R e v i s i o n and 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 Poche, 1922 ( 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 : Cercomeromorpha). Can. J . Z o o l . B a r k e r , F.D.; Covey, G.W. 1911. A new s p e c i e s of trematode from the p a i n t e d t e r r a p i n , Chrysemys m a r g i n a t a A g a s s i z . U n i v . S t u d i e s , U n i v . Nebraska. 11:193-218. B e n n e t t , H.J. 1935. Four new trematodes from r e p t i l e s . J . P a r a s i t o l . 21:83-90. B e n n e t t , H.J. 1938. A p a r t i a l c h e c k l i s t of the trematodes of L o u i s i a n a v e r t e b r a t e s . P r o c . L o u i s i a n a Acad. S c i . 4:178-181. B e n n e t t , H.J.; Sharp, C.H. 1938. H e l m i n t h p a r a s i t e s of S t e r n o t h e r u s o d o r a t u s and Terrapene C a r o l i n a t r i u n g u i s from L o u i s i a n a . P r o c . L o u i s i a n a Acad. S c i . 4:241-242. B e n n e t t , H.J.; T o b i e , J.E. 1936. New r e c o r d s of the p r e v a l e n c e and d i s t r i b u t i o n of some T e l o r c h i i n a e from Pseudemys  e l e g a n s Wied. P r o c . H e l m i n t h o l . Soc. Wash. 3:63-63. B r o o k s , D.R. 1979a. 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 . 28:299-307. B r o o k s , D.R. 1979b. New r e c o r d s f o r amphibian and r e p t i l e t r e m a t o d e s . P r o c . H e l m i n t h . Soc. Wash. 46:286-289. B r o o k s , D.R. 1980. A l l o p a t r i c s p e c i a t i o n and n o n - i n t e r a c t i v e p a r a s i t e community s t r u c t u r e . S y s t . Z o o l . 29: 192-203. 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 . 30:229-249. B r o o k s , D.R. 1985a. P h y l o g e n e t i c s and the f u t u r e of h e l m i n t h s y s t e m a t i c s . J . P a r a s i t o l . 71:719-727. B r o o k s , D.R. 1985b. H i s t o r i c a l e c o l o g y : a new approach t o s t u d y i n g the e v o l u t i o n of e c o l o g i c a l a s s o c i a t i o n s . Ann. M i s s o u r i B o t . Gard. 72:660-680. B r o o k s , D.R.; Buckner, R.L. 1976. Some P l a t y h e l m i n t h p a r a s i t e s of S i r e n s (Amphibia: S i r e n i d a e ) from N o r t h A m e r i c a . J . P a r a s i t o l . 62:906-909. B r o o k s , D.R.; Fus c o , A.C. 1978. Some D i g e n e t i c trematodes from caudate amphibians i n the s o u t h e a s t e r n U n i t e d S t a t e s . J . M i s s i s s i p p i Acad. S c i . 23:95-99. 45 B r o o k s , D.R.; Mayes, M.A. 1975. P l a t y h e l m i n t h s of Nebraska t u r t l e s w i t h d e s c r i p t i o n s of two new s p e c i e s of S p i r o r c h i d s (Trematoda: S p i r o r c h i i d a e ) . J . P a r a s i t o l . 61:403-406. B r o o k s , D.R.; Mayes, M.A. 1976. T e l o r c h i s g u t t u r o s i sp. n. ( T r e m a t o d a : T e l o r c h i i d a e ) from Graptemys pseudogeographica Gray i n Nebraska, w i t h r e p o r t s of a d d i t i o n a l s p e c i e s of trematodes from Nebraska t u r t l e s . J . P a r a s i t o l . 62:901-905. B r o o k s , D.R.; O'Grady, R.T.; G l e n , D.R. 1985. P h y l o g e n e t i c a n a l y s i s of the Digenea ( P l a t y h e l m i n t h e s : Cercomeria) 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 y r d , E.E. 1937. The trematode p a r a s i t e s from a r e d - b e l l i e d water snake, F a r a n c i a a b a c u r a . P a r a s i t o l o g y 29:359-364. B y r d , E.E.; Denton, J.F. 1938. New trematodes of the s u b f a m i l y R e n i f e r i n a e , w i t h a d i s c u s s i o n of the s y s t e m a t i c s of the genera and s p e c i e s a s s i g n e d t o the s u b f a m i l y group. J . P a r a s i t o l . 24:379-401. C a b l e , R.M.; Sanborn, C.R. 1970. Two o v i d u c t f l u k e s from r e p t i l e s i n I n d i a n a : T e l o r c h i s compactus sp. n. and a p r e v i o u s l y d e s c r i b e d s p e c i e s . P r o c . H e l m i n t h o l . Soc. Wash. 37:211-215. C h a n d l e r , A.C. 1923. Three new trematodes from Amphiuma means. P r o c . U.S. Nat. Mus. 63:1-7. Conant, R. 1975. A f i e l d g u ide t o r e p t i l e s and amphibians of e a s t e r n / c e n t r a l N o r t h American. Houghton M i f f l i n Co., B o s t o n . 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 e o g r a p h y : 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 71:273-281. C r o i z a t , L.; N e l s o n , G.; Rosen, D.E. . 1974. C e n t e r s of o r i g i n and r e l a t e d c o n c e p t s . S y s t . Z o o l . 3:265-287. D o l l f u s , R.P. 1929. Sur l a genre T e l o r c h i s . Ann. P a r a s i t o l . 7:30-132. Dougherty, E.C. 1949. The phylogeny of the nematode f a m i l y M e t a s t r o n g y l i d a e L e i p e r (1909): a c o r r e l a t i o n of host and symbiote e v o l u t i o n . P a r a s i t o l o g y 39:222-234. F a r r i s , J.S. 1970. Methods of computing Wagner t r e e s . S y s t . Z o o l . 19:83-92. F i n k , W.L. 1982. The c o n c e p t u a l r e l a t i o n s h i p between ontogeny and phylogeny. P a l e o b i o l o g y 8:254-264. 46 F u t u y m a , D . J . ; S l a t k i n , M. 1 9 8 3 . C o e v o l u t i o n . S i n a u e r a n d A s s o c i a t e s I n c . , M a s s a c h u s e t t s . G o l d b e r g e r , J . 1 9 1 1 . On some new p a r a s i t i c t r e m a t o d e s o f t h e g e n u s T e l o r c h i s . H y g . L a b . B u l l . 7 1 : 3 6 - 4 8 . H a r r i s o n , L . 1 9 1 4 . T h e M a l l o p h a g a a s a p o s s i b l e c l u e t o b i r d p h y l o g e n y . A u s t r a l i a n Z o o l . 1 : 7 - 1 1 . H a r w o o d , P.D. 1 9 3 2 . T h e h e l m i n t h s p a r a s i t i c i n t h e a m p h i b i a a n d r e p t i l e s o f H o u s t o n , T e x a s a n d v i c i n i t y . P r o c . U.S. N a t . M u s . 8 1 : 1 - 7 1 . H e n n i g , W. 1 9 6 6 . 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 , U r b a n a . H o p k i n s , G.H.E. 1 9 4 2 . T h e M a l l o p h a g a a s a n a i d t o t h e c l a s s i f i c a t i o n o f b i r d s . I b i s 6 : 9 4 - 1 0 6 . I n g l e s , L . G . 1 9 3 0 . A new s p e c i e s o f T e l o r c h i s f r o m t h e i n t e s t i n e o f C l e m m y s m a r m o r a t a . J . P a r a s i t o l . 1 7 : 1 0 1 -1 0 3 . K l u g e , A.G.; F a r r i s , J . S . 1 9 6 9 . Q u a n t i t a t i v e p h y l e t i c s a n d t h e e v o l u t i o n o f A n u r a n s . S y s t . Z o o l . 1 8 : 1 - 3 2 . L o o s s , A. 1 8 9 9 . W e i t e r e b e i t r a g e z u r k e n n t n i s d e r t r e m a t o d e n f a u n a A e g y p t e n s . Z o o l . J a h b r . S y s t . 1 2 : 5 2 1 - 7 8 4 . L u e h e , M. 1 8 9 9 . Z u r k e n n t n i s e i n i g e r D i s t o m e n . Z o o l . A n z . 2 2 : 5 2 4 - 5 3 9 . L u e h e , M. 1 9 0 0 . U b e r e i n i g e r D i s t o m e n u a s s c h l a n g e n u n d e i d e c h s e n . C e n t r . B a k t . 2 8 : 5 5 6 - 5 6 6 . L u n d b e r g , J . G . 1 9 7 2 . W a g n e r n e t w o r k s a n d a n c e s t o r s . S y s t . Z o o l . 2 1 : 3 9 8 - 4 1 3 . M a c C a l l u m , G.A. 1 9 1 9 . N o t e s o n t h e g e n u s T e l o r c h i s a n d o t h e r t r e m a t o d e s . Z o o p a t h o l o g i c a , N.Y. 1 : 7 7 - 9 8 . M a c C a l l u m , G.A. 1 9 2 1 . S t u d i e s i n H e l m i n t h o l o g y . Z o o p a t h o l o g i c a , N.Y. 1 : 1 3 7 - 2 8 4 . M a c d o n a l d , C.A.; B r o o k s , D.R. I n p r e s s . A new s p e c i e s o f T e l o r c h i s L u e h e , 1 8 9 9 ( D i g e n e a : T e l o r c h i i d a e ) f r o m t h e y e l l o w - b e l l i e d t u r t l e , C h r y s e m y s s c r i p t a s c r i p t a S c h o e p f f , 1 7 9 2 . C a n . J . Z o o l . M a r t i n , D.R. 1 9 7 2 . D i s t r i b u t i o n o f h e l m i n t h p a r a s i t e s i n t u r t l e s . n a t i v e t o s o u t h e r n I l l i n o i s . T r a n s . I l l i n o i s S t a t e A c a d . S c i . 6 5 : 6 1 - 6 7 . 47 McMullen, D.B. 1934. The l i f e h i s t o r y of the t u r t l e trematode, C e r c o r c h i s medius. J . P a r a s i t o l . 20:249-250. McMullen, D.B.; Roudabush, R.L. 1936. A new s p e c i e s of trematode C e r c o r c h i s c r y p t o b r a n c h i from C r y p t o b r a n c h u s  a l l e g a n i e n s i s . J . P a r a s i t o l . 22:516-517. M e t c a l f , M.M. 1929. P a r a s i t e s and the a i d they g i v e i n problems of taxonomy, g e o g r a p h i c a l d i s t r i b u t i o n , and pale o g e o g r a p h y . Smith. M i s c . C o l l . 81:1-36. N a s i r , P. 1974. R e v i s i o n of genera Acanthostomum L o o s s , 1899 and T e l o r c h i s Luehe, 1899 (Trematoda: Digenea) w i t h r e d e s c r i p t i o n of Acanthostomum (Acanthostomum) scyphocephalum (Braun, 1899) and T e l o r c h i s a c u l e a t u s (von L i n s t o w , 1879) Braun, 1901. R i v . P a r a s s i t . 35:1-22. 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 York. P e r k i n s , M. 1928. A re v i e w of the T e l o r c h i i n a e , a group of d i s t o m i d t r e m atodes. P a r a s i t o l o g y . 20:336-356. P r i c e , P.W. 1980. E v o l u t i o n a r y B i o l o g y of P a r a s i t e s . P r i n c e t o n U n i v e r s i t y P r e s s , P r i n c e t o n , New J e r s e y . Rohde, K. 1982. E c o l o g y of Ma r i n e P a r a s i t e s . U n i v e r s i t y of Queensland P r e s s , S t . L u c i a , A u s t r a l i a . S c h e l l , S.C. 1970. How t o know the trematodes. Wm. C. Brown Co., Iowa. S t a f f o r d , J . 1900. Some u n d e s c r i b e d trematodes. Z o o l . J a h r b . S y s t . 13:399-414. S t a f f o r d , J . 1905. Trematodes from Canadian v e r t e b r a t e s . Z o o l . Anz. 28:681-694. S t u n k a r d , H.W. 1915. Notes on the trematode genus T e l o r c h i s w i t h d e s c r i p t i o n s of new s p e c i e s . J . P a r a s i t o l . 2:57-66. S t u n k a r d , H.W.; F r a n z , R. 1977. P a r a t e l o r c h i s d o l l f u s i n. g., n. s p . , a d i g e n e t i c trematode from the s t r i p e d swamp snake, Regina a l l e n i : s y s t e m a t i c and taxonomic c o n s i d e r a t i o n s . T r a n s . Amer. M i c r o s . Soc. 96:381-389. W a i t z , J.A. 1960. T e l o r c h i s b o n n e r e n s i s n. sp. (Trematoda: Digenea) from the i n t e s t i n e of l a r v a l Ambystoma  macrodactylum B a i r d , from n o r t h e r n Idaho. J . P a r a s i t o l . 46:815-818. 48 W a t e r t o r , J.L. 1967. I n t r a s p e c i f i c v a r i a t i o n of a d u l t T e l o r c h i s b o n n e r e n s i s (Trematoda: T e l o r c h i i d a e ) i n amphibian and r e p t i l e h o s t s . J . P a r a s i t o l . 53:962-968. Watrous, L.E.; Wheeler, Q.D. 1981. The out-group comparison method of a n a l y s i s . S y s t . Z o o l . 30:1-11. Wharton, G.W. 1940. The genera T e l o r c h i s , P r o t e n e s , and A u r i d i s t o m u m (Trematoda: R e n i f e r i d a e ) . J . P a r a s i t o l . 26:497-518. Wheeler, Q.D.; B l a c k w e l l , M. 1984. F u n g u s - I n s e c t R e l a t i o n s h i p s . Columbia U n i v . P r e s s . W i l e y , E.O. 1981. P h y l o g e n e t i e 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. Yamaguti, S. 1958. Systema Helminthum. I n t e r s c i e n c e P u b l i s h e r s , New York, N.Y. Yamaguti, S. 1971. S y n o p s i s of d i g e n e t i c trematodes of v e r t e b r a t e s . Two volumes. Tokyo: K e i g a k u P u b l i s h i n g Co. Z e l i f f , C C . 1937. A new s p e c i e s of trematode from the mud-eel ( S i r e n l a c e r t i n a ) . P r o c . U.S. Nat. Mus. 84:223-226. 49 APPENDIX A T a b l e I - C h a r a c t e r d a t a f o r T e l o r c h i s s p e c i e s Codes 0, 1, and 2 i d e n t i f y p a r t i c u l a r c h a r a c t e r s . Code 0 i n d i c a t e s the p l e s i o m o r p h i c , or p r i m i t i v e s t a t e . Code 1 i n d i c a t e s a t r a i t d e r i v e d from 0; code 2 i n d i c a t e s a t r a i t d e r i v e d from 1. , . . 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 T. , . . 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 0 T, , . . 1 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 0 T. , . . 1 0 1 0 0 0 0 0 1 1 0 0 0 0 0 0 1 0 0 1 T. a u r i d i s t o m i . , . . 1 0 1 1 0 0 0 0 1 1 0 0 0 0 0 0 1 0 0 1 T. , . . 1 0 1 0 0 0 0 0 1 1 0 1 0 1 0 0 1 0 0 1 T. . . . 1 1 1 0 0 0 0 0 1 1 1 0 1 0 1 0 1 0 0 1 T. . . . 1 1 1 0 1 0 0 1 1 1 1 0 0 0 0 0 1 0 0 1 T. ... 1 1 1 001 1 01 1 0 0 0 0 0 0 1 001 T. s i n g u l a r i s .. , . . 2 1 1 0 0 0 1 0 1 1 0 0 0 0 0 1 1 1 1 1 T. a t t e n u a t u s .. , . . 2 1 1 0 0 0 1 0 1 1 0 0 1 0 0 1 1 0 0 1 50 Tab l e I I - Ranges of sucker t o pharynx r a t i o f o r T e l o r c h i s s p e c i e s LEGEND: Os=Oral s u c k e r ; V s = V e n t r a l s u c k e r ; Ph=Pharynx.  Os: Ph Vs=Ph 1- s i r e n i s 1 :0 .42- 0.43 1 :0 .37-0.43 T. s t u n k a r d i 1 :0 .32- 0.37 1 :0 .28-0.52 T. c o r t i 1 :0 .41- 0.66 1 :0 .48-0.88 T. a u r i d i s t o m i 1 :0 .29- 0.32 1 :0 .52-0.64 1 ' anqustus 1 :0 .50- 0.75 1 :0 .53-1.00 1 - s c a b r a e 1 :0 .46- 0.55 1 :0 .48-0.56 T. c h e l o p i 1 :0 .41- 0.75 1 :0 .49-0.92 T. r o b u s t u s 1 :0 .44- 0.70 1 :0 .46-1.00 T. s i n q u l a r i s 1 :0 .65- 0.86 1 :0 .70-0.77 T. a t t e n u a t u s 1 :0 .49- 0.62 1 :0 .53-0.84 51 F i g u r e 1 - Body shapes of t e l o r c h i i d s (a) o v a l body; (b) l i n g u i f o r m body; (c) elongate body; f i l i f o r m body (redrawn from S c h e l l , 1970). 51a d 52 F i g u r e 2 - M u s c u l a r i t y of c i r r u s sac (a) m u s c u l a r , r o b u s t c i r r u s s a c ; (b) l o n g , t h i n c i r r u s s a c . 52a 53 F i g u r e 3 - P o s i t i o n of c i r r u s sac (a) a t o v a r i a n l e v e l ; (b) midway between acetabulum and o v a r y ; (c) a t a c e t a b u l a r l e v e l . 53a 5 4 F i g u r e 4 - P o s i t i o n of g e n i t a l pore (a) p r e a c e t a b u l a r , s l i g h t l y l e f t of median; (b) v e n t r a l t o l e f t cecum; (c) d o r s o l a t e r a l t o l e f t cecum. 54a g-pore 55 F i g u r e 5 - U t e r i n e c o n f i g u r a t i o n (a) i r r e g u l a r l y c o i l e d ; (b) c o i l e d a s c e n d i n g and d e s c e n d i n g l o o p s . 55a 56 F i g u r e 6 - S t r u c t u r e of v i t e l l i n e f o l l i c l e s (a) l a t e r a l , c l u s t e r e d groups; (b) c o n t i n u o u s l a t e r a l bands. 56a vitelline follicles 57 F i g u r e 7 - T e l o r c h i s s i r e n i s , v e n t r a l view F i g u r e 8 - T e l o r c h i s s t u n k a r d i , v e n t r a l view 57a 58 F i g u r e 9 - T e l o r c h i s F i g u r e 1 0 - T e l o r c h i s F i g u r e 11 - T e l o r c h i s c o r t i , v e n t r a l view a u r i d i s t o m i , v e n t r a l view a n g u s t u s , v e n t r a l view 58a 59 F i g u r e 12 - T e l o r c h i s s c a b r a e , v e n t r a l view F i g u r e 13 - T e l o r c h i s c h e l o p i , v e n t r a l view F i g u r e 14 - T e l o r c h i s r o b u s t u s , v e n t r a l view 59a 60 F i g u r e 15 - T e l o r c h i s s i n g u l a r i s , v e n t r a l view F i g u r e 16 - T e l o r c h i s a t t e n u a t u s , v e n t r a l view 60a 61 F i g u r e 17 - T e l o r c h i s compactus, v e n t r a l view 61a 62 F i g u r e 18 - P h y l o g e n e t i c t r e e of N o r t h American T e l o r c h i s LEGEND: (1) t e s t e s a t p o s t e r i o r of body, tandem; (2) u t e r u s c o i l e d a s c e n d i n g and d e s c e n d i n g l o o p s ; (3) body e l o n g a t e ; (4) r a t i o of body l e n g t h t o body w i d t h g r e a t e r than 4:1; (5) a c e t a b u l a r w i d t h l e s s than o r a l s u c k e r w i d t h ; (6) v i t e l l i n e f o l l i c l e s i n c o n t i n u o u s l a t e r a l bands; (7) o r a l s u c k er w i t h a n t e r o l a t e r a l l a p p e t s ; (8) c i r r u s sac ends a t a c e t a b u l a r l e v e l ; (9) g e n i t a l pore d o r s o l a t e r a l t o l e f t cecum; (10) body l e n g t h g r e a t e r than 4.8 mm; (11) c i r r u s sac t h i c k , m u s c u l a r ; (12) c i r r u s sac ends midway between acetabulum and o v a r y ; (13) g e n i t a l pore v e n t r a l t o l e f t cecum; (14) prominent p h a r y n g e a l g l a n d s ; (15) t h i c k e n e d c e c a l e p i t h e l i u m a t p o i n t of b i f u r c a t i o n ; ( 1 6 ) c e c a l b i f u r c a t i o n l e s s than 6% TBL from a n t e r i o r end; (17) esophagus l a c k i n g ; (18) body f i l i f o r m ; (19) ovary c l o s e r t o t e s t e s than acetabulum; (20) metraterm w i t h muscular b u l b ; (21) g e n i t a l a t r i u m p r e s e n t ; (22) c i r r u s sac ends midway between acetabulum and ovary ( t h e a s t e r i s k [*] i n d i c a t e s t h a t t h i s i s a homoplasious c h a r a c t e r ) . T sirenis T. stunkordi T corti T. auridistomi T angustus T. scobroe oi oi T chelopi T. robustus T. singuloris ro ro — .9 r o x T . attenuatus 63 F i g u r e 19 - Map of c o n f i r m e d l o c a l i t i e s f o r T e l o r c h i s c o r t i 63a • •reported localities 64 F i g u r e 20 - Map of r e p o r t e d l o c a l i t i e s f o r T e l o r c h i s c o r t i 64a 65 F i g u r e 21 - P a r t i a l p h y l o g e n e t i c t r e e of t u r t l e t a x a (Used w i t h p e r m i s s i o n from L i n d a Dryden, U n i v . pf K a n s a s ) . Kinosternon Sternotherus Chelydro Clemmys Terrapene Emydoidea Deirochelys Groptemys Chrysemys scripto scripta Chrysemys scripta elegans Chrysemys ptcta 66 F i g u r e 22 - H y p o t h e s i s of h o s t - p a r a s i t e c o e v o l u t i o n (a) P a r t i a l p h y l o g e n e t i c t r e e of t u r t l e t a x a , w i t h the congruent (100% f i t ) p a r a s i t e s p e c i e s mapped on. LEGEND: 1= K i n o s t e r n o n ; 11= S t e r n o t h e r u s ; 111= C h e l y d r a ; IV= Clemmys; V= Te r r a p e n e ; VI= D e i r o c h e l y s ; VII= Emydoidea; V I I I = Graptemys; IX= Chrysemys  s c r i p t a s c r i p t a ; X= Chrysemys s c r i p t a e l e g a n s ; XI= Chrysemys  p i c t a . (b) P h y l o g e n e t i c t r e e of congruent p a r a s i t e s p e c i e s 66a 67 F i g u r e 23 - P a r t i a l p h y l o g e n e t i c t r e e of host t a x a w i t h s e c o n d a r i l y e v o l v e d p a r a s i t e s p e c i e s mapped on LEGEND: 1= K i n o s t e r n o n ; 11= S t e r n o t h e r u s ; 111= C h e l y d r a ; IV= Clemmys; V= Terra p e n e ; VI= D e i r o c h e l y s ; VII= Emydoidea; VI11 = Graptemys; IX= Chrysemys s c r i p t a s c r i p t a ; X= Chrysemys s c r i p t a e l e g a n s ; XI= Chrysemys p i c t a ; XII= F a r a n c i a a b a c u r a . 67a 68 F i g u r e 24 - P h y l o g e n e t i c t r e e of T e l o r c h i s s p e c i e s i n amniotes The broken l i n e s i n d i c a t e s e c o n d a r i l y e v o l v e d s p e c i e s . T corti T ouridistomi T onqustus T. scabrae T chelopi T robustus T singuloris T attenuatus 69 F i g u r e 25 - P o s s i b l e c o m b i n a t i o n s of host range and s p e c i f i c i t y Each box r e p r e s e n t s a d i f f e r e n t t y pe of h o s t ; each dot i s p a r a s i t e of the same s p e c i e s . 69a broad host range low specificity • broad host range high specificity • • m • narrow host range low specificity • • narrow host range high specificity • • m • 70 F i g u r e 26 - Host s p e c i f i c i t y of T e l o r c h i s s p e c i e s i n amniotes Numbers i n p a r e n t h e s e s i n d i c a t e the number of h o s t s t h a t each s p e c i e s has been r e p o r t e d from. Note i n c r e a s i n g host s p e c i f i c i t y among p r i m a r i l y c o e v o l v e d s p e c i e s ( I , V - V I I I ) . LEGEND: 1= T e l o r c h i s c o r t i ; 11= T e l o r c h i s a u r i d i s t o m i ; 111= T e l o r c h i s a n g u s t u s ; IV= T e l o r c h i s s c a b r a e ; V= T e l o r c h i s c h e l o p i ; VI= T e l o r c h i s r o b u s t u s ; V I I = T e l o r c h i s s i n g u l a r i s ; V I I I = T e l o r c h i s a t t e n u a t u s . 70a 71 F i g u r e 27 - Summary cladogram of the h y p o t h e s i z e d e v o l u t i o n a r y h i s t o r y of the' N o r t h American s p e c i e s of T e l o r c h i s T sirenis (2) T. stunkardi (6) T. corti (15) • X ouridistomi (I) T angustus (2) .•J. scobroe (I) T chelopi (4) T robustus (3) _. singuloris (2) T ottenuotus (I) 

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