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The systematics of the freshwater sculpins of British Columbia. McAllister, Don E. 1957-12-31

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THE SYSTEMATICS OF THE FRESHWATER SCULPINS OF BRITISH COLUMBIA  by D.E. McAllister  A thesis presented i n partial fulfilment of the requirements for the degree of Master of Arts. i n the Department of Zoology We accept this thesis as conforming to the required standard  The University of British Columbia April, 1957  In presenting the  t h i s t h e s i s i n p a r t i a l f u l f i l m e n t of  r e q u i r e m e n t s f o r an advanced degree at the  University  o f B r i t i s h Columbia, I agree t h a t the L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e f o r r e f e r e n c e and agree t h a t p e r m i s s i o n f o r e x t e n s i v e f o r s c h o l a r l y purposes may  study.  copying of t h i s  be g r a n t e d by the Head o f  Department o r by h i s r e p r e s e n t a t i v e .  Department  The U n i v e r s i t y of B r i t i s h Columbia, Vancouver 3, Canada.  my  be a l l o w e d w i t h o u t my w r i t t e n  of  thesis  I t i s understood  t h a t c o p y i n g or p u b l i c a t i o n o f t h i s t h e s i s g a i n s h a l l not  I further  permission.  ABSTRACT A systematic study was made of the genus Cottus, emphasizing the species of British Columbia.  Some five thousand specimens from  the Institute of Fisheries museum were used to construct distribution maps. Intensive examination before and after clearing and staining with alizarin or X-raying was made of 745 B.C. specimens and several exotic species.  Color pattern, sex body proportions, prickles and  the number of f i n rays, lateral line pores, operculomandibular  pores,  we ve  caudal vertebrae, and preopercular spines noted. A  employing these characters were constructed.  Specific descriptions  A new species found by  Bailey i s reported and described; philonips i s synonomized with cognatus.  Intraspecific variation i n meristic characters showed  modification with habitat, distance from the sea, altitude, latitude, populations and i n some cases with sex.  Interspecific comparisons  revealed differences which were evaluated and made into a key of B.C. species.  Supraspecific study showed the existence of three species  groups having different counts of caudal vertebrae and other characteristics.  A key i s given to the species groups.  1 ACKNOWLEDGEMENTS To Dr. C.C.Lindsey the author i s deeply and sincerely grateful for suggesting the problem, for his guidance, suggestions and criticism throughout the study.  His extensive collecting has aided greatly i n  the addition of new material. Dr. R.M.Bailey of the University of Michigan has kindly commented on some of my ideas, given me some of his own and sent specimens of eastern Cottus.  I am also grateful to Dr. W.B.Scott, Dr. E.C.Raney and r . D  C.Bond for collections of other species. specimens of Cottus princeps.  Dr. G.S.Myers generously loaned  Dr. C.R.Robins and Dr. C.L.Hubbs have lent  me their encouragement. The author is indebted to T.Bilton, D.R.Foskett, H.Godfrey, G.F.Hartman, J.E.Mason, R.T.Myren, P.R.Nelson, T.G.Northcote and S.Qadri for donation of specimens or aid i n collecting. Thanks are given to the X-ray technician at U.B.C. hospital for x-raying specimens. Employment as assistant curator i n the Institute of Fisheries by Dr. P.A.Larkin and H.R.MacMillan helped make this study possible.  TABLE OF CONTENTS Page INTRODUCTION  .  2  ORGANIZATION  3  LITERATURE ON MERISTIC VARIATION  3  Table 1. Experimental studies of meristic variation  ...  GEOGRAPHIC VARIATION  5 9  Table 2. Examples of latitudinal variation  11  METHODS . .  12  DESCRIPTIONS OF AND VARIATION IN INDIVIDUAL SPECIES OF B.C. SCULPINS  18  Cottus asper Richardson  18  Table 3» Mean intensity of prickling i n different habitats  22  Table 4 . Percent of individuals prickled i n each area . .  22  Table 5. Meristic differences between lake and stream populations . . Table 6. Percent of individuals prickled i n different areas of the body i n coastal and non-coastal populations.  23 25  Table 7. Frequency distribution of meristics of coastal and non-coastal populations.  26  Table 9. Relation of meristics to altitude i n Cottus asper  28  Table 10. Influence of temperature on meristics  29  Table 11. Latitudinal variation i n f i n ray and vertebral counts . . Cottus cognatus Richardson . Table 12. Latitudinal variation Table Sex differences i n meristics . . . . . . . . . . .  31 36 38 44  Table lij.. Comparison of Cottus philonips and C. cogndus. . .  44  Table of Contents Continued Page Cottus n.sp  .  47  Cbttus hubbsi Bailey and Dimiek  50  Table 16. Meristic differences i n Canadian and American Cottus hubbsi . . . . Cottus rhotheus (Rosa Smith) Table 15. Sex differences  52 53 55  Cottus aleuticus Gilbert . . . . . . . . . . . . . . . . . . .  57  Table 16a. Comparison of meristics of coastal and non-coastal Cottus aleuticus . . . .  59  Table 17. Latitudinal variation i n vertebrae . . . . . . . . .  59  Cottus r i c e i (Nelson) . . . . . . . . . . . . . . . . . . . . .  61  Table 19. Changes i n meristics of Cbttus r i c e i from southwest to northwest i n North America . .  64  COMPARISON OF SPECIES AND INTERSPECIFIC VARIATION  65  Table 20. Meristic comparison of Cottus r i c e i , C.sibiricus and C. spinulosus . . . Table 21. Number of chin or symphyseal pores  67 71  Table 23. Numer of individuals of various species having one or two spines on the f i r s t dorsal basal . . . . . .  73  Table 24. Number of basals below the dorsal fins . . . . . . .  75  Table 25. Variation i n minor caudal rays SUPRASPECIFIC RELATION IN COTTUS  76 88  .  Table 26 Comparative ecology of B.C. Cottus . . . . . . . . . .  89  Table 27. Range of caudal vertebrae  91  . . . . . . . .  Table 28. Dorsal spine range i n groups I and II .  92  Table 29. Ranges of dorsal rays i n groups I and II  93  Table 30. Ranges of anal rays i n group I and I I &©mU3IQJS LITERATURE CITED  94 9£ 104  ILLUSTRATIONS  Figure  Page  1.  Areas of prickling . .  15  2.  Means of ray counts of Cottus co^natus from different river systems . . . .  41  2a. Probable redispersal of Cottus cognatus from two centres following the Wisconsin glaciation . . .  41a  3.  Shapes and proportions of cottine prickles  70  4.  Shape of head and preopepcular spine  82  5*  Symphyseal pores  82  6.  Posterior nostrils  7.  Meristic variation i n B.C. Cbttus  86  8.  Distribution of B.C.species of Cottus  87  9.  Cottus asper and C.aleuticus  10. Cottus n.sp_. ,C. cognatus, C. hubbsi 11. Cottus rhotheus and °.ricei  . . . . . . .  82  101 102 103  2 INTRODUCTION  The genus Cottus i s a closely-knit group of small fish inhabiting the fresh and brackish waters of the holarctic region.  For several  reasons they have been a challenge to the systematist.  Convergent and  divergent evolution i n characters, such as dentition and number of pelvic f i n rays, have been misleading.  The variability of populations has led  to the naming of -invalid species.  Phenotypic and genotypic variation i s  so great that characters normally used i n definition of species cannot be applied. This thesis attempts to clarify the definitions of B.C. species of Cottus, to determine their relations 'with other species, and to find species groups within the genus.  A intensive study has been made of the n  variation, particularly clinal, of British Columbia species. Literature research has enabled suggestion of possible causes of variation.  Dif-  ferences between B.C. species have been determined and summarized in a key.  Some exotic species were examined and this and the literature has  allowed determination of relationships of species and species groups.  3 ORGANIZATION This thesis i s concerned with the variation of taxonomiccharacters within a single species, between species, and between groups of species. There are five main sections.  The f i r s t reviews the literature on  and vdiy meristics (serially repeated parts) vary. methods.  how  The second describes  The third section describes each B.C. species and i t s variation.  The fourth deals with interspecific differences and the relations of B.C. species, and presents a key to B.C. species.  The last section discusses  the species groups i n Cottus - a l l species, and terminates i n a key.  LITERATURE ON MERISTIC VARIATION One of the problems i n taxonomy of Cottus has been the lack of knowledge of the variability, and the causes of variability i n taxonomic characters.  Since experiments on raising sculpins under different con-  ditions failed, the possible causes of variation must be derived mainly from the literature on other genera.  The discussion which follows i s  limited to serially repeated or meristic characters. Experiments on Variation The raising of fish eggs under constant environmental conditions has revealed two major controls of meristics.  Environmental differences  during development may modify meristic characters.  Differences i n fac-  tors such as temperature may result in different numbers of f i n rays i n lots of young from the same parent., heredity may influence  the number of parts in the progeny, for when offspring from different parents are raised under identical conditions the characters of the progeny are found to be similar to those of their parents.  Literature  on experiments on meristic variation i s summarized i n Table I. Heredity . Schmidt (1917, 1919) (see Table I) showed that the tendency for the number of dorsal f i n rays can be inherited. Gabriel (1944) found that high parental numbers of vertebrae were associated with high vertebral numbers i n the offspring. According to Taning (1952) late determined characters - dorsal and pectoral rays ape less subject to genetic control than are early determined characters such as vertebrae. Lindsey (1952) stated that every meristic character'studied in Gasterosteus aculeatus showed genetic differences. Environmental Effects Table I l i s t s the species in which certain environmental factors have been shown to produce differences i n the serial characters.  It  is evident that average temperature, changes i n temperature, salinity, oxygen and carbon dioxide pressure and light intensity have been able to modify certain characters during development.  Scales, total verte-  brae, caudal vertebrae, dorsal, anal, caudal and pectoral f i n rays, dorsal and anal spines, the basals of dorsal and anal rays have shown themselves modifiable. Temperature Most investigators have reared f i s h at only two temperatures.  TABLE I EXPERIMENTAL STUDIES OF MERISTIC VARIATION AUTHOR  SPECIES  MERISTIC  OBSERVED CORRELATION  Temperature Bailey and Gosline, 1955  Etheo stoma nigrum  Vert.  Negative  Dannevig, A. 1950  Pleuronectes platessa  Vert.  Negative  Fox, W. 1948  Snake - Thamno- Several phis elegans • scale atratus series  Gabriel,M.L. 1944  Fundulus heteroclitus  Vert.  Negative, hereditary  Heuts, M.J. 1947b  Gasterosteus aculeatus Marine and freshwater populations  D, A, P.  Modified differently i n two groups and at different salinitie s  Lindsey,C.C. 1952  Gasterosteus aculeatus  D-jbasals, D and A basals, C Vert., P.  Positive Negative Lowest at intermediate temp. A l l hereditary  Pygosteus pungitius  T>2 and A  Positive  basals Vert.  Lowest at intermediate temp.  Macropterus opercularus  A Vert., A and D basals, A spines  2  2  Positive  Negative Negative  Mottley,C.M. 1934  Salmo jgairdneri  Negative Lateral line scales  ibid 1937  Salmo gairdneri  Vert.  Positive and negative  6 TABLE I (continued) AUTHOR  SPECIES  MERISTIC  OBSERVED CORRELATION  Temperature Positive and hereditary-  Schmidt, J 1917, 1919  Lebistes reticulatus  ibid 1920  Zoarces viviparous  Vert.  Modified by salinity of temperature.  Tailing, A. 1952  Salmo trutta  Vert. D,A,P."  Lowest at intermediate temp. Highest at intermediate temp. A l l hereditary.  Salmo trutta  Vert.  Radical effect at 100 day-degrees  McHugh, J.L. 1954  Leuresthes tennuis  Vert.  Negative  Vibert, R. 1953  Salmo salar  Vert.  Partial darkness produced most  Gasterosteus aculeatus" Marine and freshwater populations  D A,P.  Modified differently i n two groups and at different temperatures.  2  2  Temperature Change Taning, A. 1946 Light Intensity  Salinity Heuts, M.J. 1947b  2  Other Factors Oxygen concentration Salmo trutta Vert. Taning, A 1952 Carbon dioxide concentration Vert. Salmo trutta Taning, A 1952 D^ = dorsal spines D2 = dorsal rays A - anal rays  Negative Positive P = pectoral rays Negative negative correlation with factor =  7 Frequently unwarranted conclusions have been drawn; e.g., that vertebrae increase with developmental temperature.  Schmidt, Taxiing, and  Lindsey have shown, using three or more temperatures, that the relationship between temperature and vertebrae i s "V" shaped, with the highest or lowest vertebral number at intermediate temperatures. Furthermore, Taning (1952) found that moderate temperature changes during a certain sensitive period of development could cause large d i f ferences in the number of vertebrae.  This effect and the effects of  sustained temperature during development suggest great caution be used i n the application of meristic characters i n taxonomy.  If populations  from locals of quite different temperatures are meristically different, i t should not be assumed that the difference is genetic.  Ideally, eggs  from the two populations i n question should be raised under identical conditions before they are declared to be taxonomically distinct. Salinity Experiments by several workers (see Table I) have shown that salinity may modify meristic characters. and phosphates had no effect.  Heuts found that nitrates  It seems likely that the chlorides are  the ingrediant causing the differences. Freshwater species might possibly be affected similarly by other dissolved solids. Light McHugh (1954) found that light intensity could influence the number of vertebrae i n the grunion, Leuresthes tennuis.  Light was found to be  more important i n determining vertebrae than were temperature and  8 temperature and salinity, the results of which were too variable to analyze.  Work done by the author under C.C.Lindsey indicated that the rate  at -which the vertebrae were ossified could be influenced by the intensity of light i n Catostomus catostomus, and the number of somites was affected by light-duration. These experiments are significant because they determine the effect of two factors (day-length and light intensity) which change with latitude.  Latitudinal clines i n meristic characters, often  observed i n fish, might be the result of change northward i n either of these two factors or both. Interaction It i s quite probable that the number of parts a fish has are not the result of the single effect heredity, or temperature, or salinity, or light or other factors. Probably variability and clines are the products of interaction of two or more of these factors. that temperature modified the effect of salinity.  Lindsey (1952) found Other factors also  probably interact. Biological Complications Generally speaking, i t becomes colder away from the equator.  It i s  quite possible, however, that f i s h at different latitudes spawn at the same temperature rather than at the same time of the year. would be exposed to different light conditions.  These fish  The conditions i n which  fish "select" to spawn may have a large influence upon the environment to -which the developing egg i s exposed.  9 It may inally.  be seen that a changing complex of factors change l a t i t u d -  The effect of b i o l o g i c a l factors, genetic characters and  environmental influences need to be determined before meristic c l i n e s are understood. GEOGRAPHIC VARIATION Meristic characters can be correlated with several geographic features.  M e r i s t i c characters have been shown to change with a l t i t u d e ,  l a t i t u d e , distance from the sea, s a l i n i t y and habitat. do not necessarily cause the differences, which may associated environmental factors (such as  These features  be the r e s u l t of  temperature).  L a t i t u d i n a l Variation Clines i n meristic characters with l a t i t u d e are shown to occur i n several species of several f a m i l i e s of t e l e o s t s i n Table 2.  These are  merely a sample of numerous instances i n the L i t e r a t u r e . Clines exist i n several m e r i s t i c characters such as dorsal spines, dorsal, anal and pectoral rays, vertebrae and caudal vertebrae.  In the majority of  cases there i s an increase i n m e r i s t i c parts away from the equator (see Vladykov, 1934  and Hubbs, 1926).  Clines may  also occur i n which  parts increase towards the equator or i n which they may increase both north and south.  Bailey and Gosline (1955) have found increases i n ver-  tebrae from east to west.  Some workers, such as Sato and Kato (1951)  and Egami (1954), have found no r e l a t i o n s h i p between m e r i s t i c characters i n f i s h and l a t i t u d e .  TABLE 2 11 EXAMPLES OF LATITUDINAL VARIATION IN MERISTIC CHARACTERS CLASSIFICATION CLASS TELEOSTOffl Clupeidae Clupea pallasi Engraulidae EngrauLis mordax Salmonidae Oncorhynchus tshawytscha Osmeridae Thaleichthys pacificus Cyprinidae Notemigonus crysoleucas Richardsonius balteatus Ictaluridae Ictalurus nebulosus Gadidae Cheragra chalcogramma Syngnathidae mathus californiensis Atherinidae Menidia beryllina Percxdae .several species Clinidae Gibbonsia elegans Stichaeidae Anoplarchus purpurescens Cottidae Leptocottus armatus Cottus asper Cottus rhotheus Cyclopt eridae Liparis l i p a r i s Pleuronectidae Platichthys stellatus CLASS REPTLLIA Thamnophis megalops Opheodrys vernalis Thaleophis 4 sp. Cnemidophorus sexlineatus  CHARACTER CLINE vert. A & P vert. D & A  4-  LOCALITY 35-60°;sw west NA. 30-50°;sw west N.A. 38-41 jfw west N.A. 49-56°;fw west N.A. 28-43 jfw east N.A. 49-55°;fw west N.A. w  vert. vert. anal rays anal rays  f  anal rays D 1, 2 & 3 A 1 & 2 452_  vert. A & D spines D spines 0D & A 4, D & caud.vert. ^ 2  D & caud.vert.  r  east N.A. 49-60°;sw west N.A. 28-60°; sw west N.A. 26-41°;aw. east N.A. fw; east N.A. sw; west N.A. sw; west N.A. sw; west NA. 37-50°;fw west N.A.  11  McHugh,J.L. 1954 McHugh,J.L. 1941 McGregor,E.A* 1924 Hart & McHugh 1944 Schultz, L.P. 1926 Lindsey, C.C. 1953 Hubbs, C.L. 1940 Schultz & Welander 1935 Herald, E.S. 1941 Gosline, W.A.  1248  Bailey & Gosline 1955 Hubbs, C.L. 1927 Hubbs, C.L. 1927 Hubbs, C.L. 1921b Northcote,T.G. 1950  11  Spitzbergen Vladykov, V. to Norway;sw 1224 sw;Alaska to Townsend,L.D. California 1937  D scales ^ caudal scale s -f ventral scales ^ parietal " ^  Arrow points in direction of decrease of character, north being top, south bottom of page.  SOURCE  vert.= vertebrae caud.= caudal D = dorsal rays A - anal rays P = pectoral rays  Ruthven,A.1908 Grobman,A.1941 Oliver,J.1949 Hoffman,R.1949 fw = breed i n fresh, sw, i n salt water. N.A. = North America 35-60° = degrees of latitude north of the equator.  12 a l l differ geographically and i t is possible that they are the cause of geographic variation i n meristics.  Geographic clines might well be ex-  plained i n terms of environmental clines.  Average temperature, rate of  change of temperature, light intensity, day-length, and light quality a l l change with latitude. A l l could theoretically affect meristics. It i s also possible that geographic clines are hereditary.  Lindsey  (1953) believed that the latitudinal clines i n anal rays of Richardsonius balteatus were genetic.  Clines couldbe^due to change i n gene composition  from one end of the range to the other.  These genetic clines could be  due to chance mutation and slow transmission of hereditary factors from one end of the distribution to the other.  Because of their frequency  and because they are usually in the same direction i n different groups, i t is likely that they are the result of selection, rather than chance. For instance, i t might be advantageous to have more f i n rays i n colder water because of i t s greater density.  Possibly metabolic rates or other  internal factors are clinal, and these indirectly result i n production of meristic clines. METHODS Some 5000 specimens of sculpins from the collections of the Institute of Fisheries, U.B.C. were identified or checked. made (see acknowledgements).  New collections were  Specimens were then selected for study from  the larger collections of each species.  An attempt was made to cover  the range of each species i n B.C. as well as the collection permitted. A few exotic species were also studied to determine relationships between  13 species.  Both external and internal characters were studied.  External Characters The external characters were determined f i r s t .  Certain body propor-  tions were measured using vernier calipers accurate to .1 mm.  Head  length was measured from the anterior t i p of the upper l i p to the posterior t i p of the opercular bone. Caudal peduncle depth was the least depth of that part.  Standard length was taken from the most anterior  portion of the body to the posterior edge of the hypural. Color and tubularity of the posterior nostril were noted,  •'•'he l a t -  eral line pores were counted commencing behind the operculum and ending where the lateral line ceased.  In some specimens slight interuptions  occurred at the end of the lateral line, leaving small sections of lateral line past the end of the completed portion (which are not mentioned by Robins (1954).  These extra portions were not counted.  Internal Characters To determine internal characters the specimens were stained i n alizarin and cleared i n KOH under ultraviolet radiation and glycerine by the method given by Hollister (1934)» Some were x-rayed. From cleared specimens and x-rays plates counts were made under a binocular microscope.  Dorsal spines, dorsal, caudal, anal, ventral, pectoral and  branchiostegal rays, preopercular spines, caudal vertebrae, the presence of palatine teeth, and the degree and extent of prickling were determined.  Occasionally fins were damaged i n clearing and counts could  not be made. This i s the reason why some counts of different characters  14 i n a sample are not equal. A l l of the dorsal spines were counted, even though i n some species there were two spines on the f i r s t basal.  The number of spines on the  f i r s t basal (no basals existed i n front of the f i n ) were noted - one or two.  The spines could be distinguished r e a d i l y from the rays by t h e i r  slenderness and lack of annulae. The l a s t two rays of the d o r s a l and anal f i n s were counted as one when they sat on the same basal.  This method was used so that counts  from the l i t e r a t u r e would be comparable.  This procedure i s open to some  objection, as i t i s a c t u a l l y a basal count rather than a ray count. This would be an understandable method i n groups of f i s h e s where the l a s t ray i s a c t u a l l y branched, but does not d i f f e r e n t i a t e between forms having one or several rays on the l a s t basal.  In some species of Cottus  co gnatus only one ray occurred on the l a s t basal.  The counting method  does hot separate these f i s h from f i s h having two rays on the l a s t basal. As one spine was always present i n each of the ventral f i n s i t was not designated i n counts.  This and the outermost ray are bound together  and can only be distinguished i n cleared or dissected f i n s .  Except f o r  two or three specimens with 2 or 5 rays, the ventral f i n always contained 3 or 4 rays.  In Cottus cognatus the fourth ray was absent or of varying  length, and i t s length was v i s u a l l y estimated as a small fragment 1/5, %, l / 3 , 5, 2/3, 3/4 of the longest ray.  The l e f t f i n was always counted.  The number of rays i n the pectoral f i n and i n the branchial membrane (branchiostegals) was also enumerated.  15 Counts of caudal vertebrae were made using the method given by Schultz (1930).  Wherever vertebrae are mentioned i n this paper, caudal  vertebrae are referred to, unless otherwise designated. of abdominal vertebrae were also made.  Following McHugh (1941) columns  containing abnormal vertebrae were not counted. on the l e f t preopercle was- counted.  A few counts  The number of spines  Unless the preopercle erupted into  a sharp elevation i t was not considered a spine; low bumps were not considered spines.  Unless the two inner and outer plates composing the  preopercle fused together to form a point a spine was not enumerated. Scales are absent i n Cottus; small spines, termed prickles (see f i g . 3) are present i n the skin.  The amount of the body prickled varied  between different species and within species. To evaluate differences in extent of prickling the body was divided into areas (see f i g . l ) which were designated as a  j . The intensity of prickling, that i s how  close the prickles were to one another, was also determined.  The inten-  sity was estimated and given a value of from 1 to 4, 1 being the lowest; 4 being the highest intensity.  At intensity 4 the bases of the prickles  were i n contact; at 1 they were widely dispersed, only about half a dozen prickles being present i n an area.  Figure 1. Areas of prickling.  16  Sex was determined by dissection on some individuals.  Ovaries are  round i n cross-section and covered by a definite membrane. Om breaking the membrane eggs can often be seen.  Testes are triangular i n cross-  section and have a white granular composition throughout.  Differences  are also found i n the length of the anal papilla, but this was not used i n sex determination. Ecology An indication of the ecology of different species has been obtained from the data on the field record sheets of the collections of the Institute of Fisheries (see following sample).  As the sampling method for  these collections was largely seining there are certain limitations to the data.  Seining i s probably less efficient i n fast deep water with  rocky bottom.  The.'fact that waders were mainly used while seining to  secure specimens limits the depth of collecting.  Since collections were  made mainly i n the summer with a few i n the f a l l and spring and none i n the winter, the data represents only a portion of the year.  Since these  prejudices were probably random with regard to the species, the information i s nevertheless of comparative value. ogical differences.  Ecological differences are hence discussed under  interspecific relationships.  Sometimes collections occurred i n mixed  habitats - rocky and sandy bottom. both categories.  It indicates relative ecol-  These collections were entered under  17 UNIVERSITY OF BRITISH COLUMBIA Institute of Fisheries Field Record Province or Country. County: • . Locality:  Map:  lat Water: Vegetation: Bottom: Cover: Shore: Dist. offshore: Depth of capture:.. Collected by .1 Tide: Method of capture: Orig. preserv.:  Field No :  , 1.  N., Long -  W. . . .  :  Temp.: Current: Stream width:.... Depth of water: Date: Time:  o  Synonomies Synonyms were obtained mainly from Jordan and Evermann,(1898) Schultz }  and Delacy (1936), Hubbs (1919).  Only names different from present useage  were included. Drawings Drawings showing important external features were made with the aid of a camera lucida.  These were photographed on 35 mm. film and reduced  to about 2/3 of the original size i n the prints.  18 DESCRIPTIONS OF  AND  VARIATION IN INDIVIDUAL SPECIES OF B.C. SCULPINS INTRA SPECIFIC VARIATION Cottus asper Richardson 1936  p r i c k l y sculpin  Figure 9 Synomymy Cottus asper Richardson, Fauna Bor. Amer., Fish., 295, I836 Columbia River at F t . Vancouver. Trachidermis richardsoni, Heckel, Ann.Wiener Mus., 162, 1840 Centridermichth asper, Richardson, Voyage Sulphur, Icth., 74, 1845; Gunther I860. Cottopsis asper, Girard, U.S. P a c i f i c R.R.Surv., X, F i s h . , 51, 1851, 1858; Suckley I860; Jordan and Jouy 1882. Cottopsis parvus, Girard, i b i d 1854, 1857 and 1858. Uranidea aspera, Jordan and Gilbert, Synopsis, 694, 1883 Cottus gulosus, Girard, i n Jordan, B u l l . U.S. Fish. Comm. 141, 1894; Jordan and Evermann 1898 i n part DESCRIPTION Color Olive brown sometimes tinged with yellow or plum,  ^lack mottlings  on back and sides, often i n s i x v e r t i c a l saddles, two below spinous dorsal, three below rayed d o r s a l (see F i g . 9). caudal f i n . ventrally.  Dark bar at base of  Narrow dark bands on second dorsal passing p o s t e r i o r l y and Irregular wide dark bands on caudal and pectoral f i n s .  and often abdomen covered evenly with f i n e speckles. under eye bordered by l i g h t e r zone.  Chin  Short dark bar  F i r s t d o r s a l with f a i n t dark cent-  r a l band:; prominent c h a r a c t e r i s t i c dark spot i n posterior portion; post e r i o r dorsal edge with t h i n band of orange. • L i t t l e difference i n color.of sexes, except i n the spawning season when male becomes very dark on head, body and f i n s . morphological features.  See F i g . 9 f o r the color patterns and external  19 Morphology The maximum recorded size i s 300 ram. • The usual maximum i s 150  mm.  The head i s large and the mouth i s only smaller than that of Cottus rhotheus (of B.C. species) (discussed by Northcote 1954). peduncle i s of medium depth.  The caudal  Strong teeth are present on the palatine  bones but these do not come into contact with the vomerine patch of teeth.  As i n a l l other B.C. sculpins villiform teeth are present on  the vomer, premaxi11apies,  dentaries and the upper and lower pharyngials.  Four to eight, usually five pyloric cacae are present, usually two short and three long.  The posterior nostrils usually are hot tubular, but some  preserved large specimens have semitubular nostrils.  The anal papilla  of the female i s a small bump, while that of the male i s a large f l a t tened "v".  Most authors record one large spine at the angle of the  preopercle and one smaller below.  Clearing and dissection revealed  that there are more often two smaller spines below (27 specimens) than one (9 specimens).  Prickling i s very variable i n extent and intensity.  Some have only a few i n the a x i l under the lateral line, while others are covered densely with coarse prickles except on the head and thorax. Usually they occur on the sides and back and on the dorsal side of the caudal peduncle.  They may occur i n a l l regions i n Fig. 1 (regions a - j ) .  Generally they are most dense i n regions b to e and decrease i n intensity outwards. The prickles themselves are generally large and strong, have a long sharp shaft and a f l a t or tridentat base (see Fig. 3). i s usually present on the t i p of the chin (see Fig. 5).  One pore  20 Meristic values (vertebrae and f i n rays) may  be obtained from the  section on i n t e r s p e c i f i c comparisons or from F i g . 7.  Statistical sig-  nificance of meristic differences i n the graph ( F i g . 7) may v i s u a l l y (graphical method from Hubbs and Hubbs (1953)«  be determined  The f i r s t  dorsal spines are usually placed on the f i r s t dorsal basal.  two  Usually  the l a s t spine and the f i r s t dorsal ray are placed on t h e i r own  basal  (67 specimens), occasionally they are on the same basal (9) and r a r e l y an unrayed basal e x i s t s (6). 4 rays, only two  specimens being found with 5 and two  rays out of many examined. the longest. 60 mm.  The v e n t r a l f i n almost i n v a r i a b l y contains  The innermost ray i s about % the length of  The l a t e r a l line i s usually complete i n  i n length.  specimens with 3  specimens over  Sometimes the l a t e r a l l i n e i s missing on the caudal  peduncle and i n specimens from Buttle Lake i t extends only to the middle of the rayed dorsal. may  The number of pores i n specimens over 60  vary from 32 to 43 but i s usually about 3#.  exist.  mm.  No external scales  Internal scales were apparent between the l a t e r a l l i n e pores i n  cleared specimens of a l l species.  These i n t e r n a l scales are hollow  tubes which surround and presumably support the l a t e r a l l i n e canal. Tiny holes appear at the bottom of these tubes which may or blood vessels.  Internal scales develop as the l a t e r a l l i n e forms and  are usually about equal to the number of pores. structures may  transmit nerves  I l l u s t r a t i o n s of similar  be seen i n Bolin (1952).  Distribution Figure $ gives the d i s t r i b u t i o n of Cottus asper.  The range i s quite  wide, extending from Chilkoot Lake i n southeastern Alaska - 59°30'  21 (Nichols 1908)  to Ventura River lagoon i n C a l i f o r n i a - 34°20».  Most  P a c i f i c drainages between these two points contain Cottus asper.  It i s  present also i n the upper waters of the Peace River i n the Mackenzie River system i n t o which i t has gained entrance from either the Eraser or the Skeena.  In B.C.  i t i s found i n the Peace, Stikine, Nass, Skeena,  Fraser and Columbia River systems, as w e l l as many coastal lakes and streams. GEOGRAPHIC VARIATION The number of body parts i n £. asper have been found to vary with geographical f a c t o r s . As the number of parts i s taxonomically  signifi-  cant i t i s important to know the existance and extent of effects geography may  have on m e r i s t i c characters.  Habitat P l a s t i c i t y often exists i n the characters of species having wide ecological valency.  The habitat may  be found to modify the organism  phenotypically or genotypically. P r i c k l i n g was  found to be one of the most variable characters i n  the p r i c k l y sculpin.  Some i n d i v i d u a l s are so densely p r i c k l e d that the  bases of the p r i c k l e s are almost i n contact, while i n others the p r i c k l e s are f a r apart.  The extent as well as density varies widely.  To deter-  mine i f habitat had any influence on the v a r i a b i l i t y , the i n t e n s i t y of p r i c k l i n g was tabled for three general types of habitat.  Rivers, lakes  and brackish waters (streams a mile or less from the sea) formed the c r i t e r i a f o r habitat c l a s s i f i c a t i o n .  Following are tabled the means f o r  22 i n t e n s i t y of p r i c k l i n g for each region on the body.  The percent of  i n d i v i d u a l s which possessed p r i c k l e s i n each region i s also tabled. The number of individuals and number of c o l l e c t i o n s i s included.  TABLE 3 MEAN INTENSITY- OF PRICKLING IN DIFFERENT HABITATS ( i n Cottus asper) HABITAT  AREA PRICKLED N M a  River Lake  .16  7  94 28  Brackish 15 3  b  c  .60 1.1 3.1  d  e  f  g  2.8 3-1 1.2  h  .71  i  j  .62 2.2  Mean  .49 1.6  .571 1.68 2.53 2.22 2.47 1-32 .692 -531 1.82 .391 1.42 .00 1.5  2.4  2.3  2.2.  .47 .07  .00 1.9  .00 l.iJfi  N = number of i n d i v i d u a l s M = number of samples  TABLE 4 PERCENT OF INDIVIDUALS PRICKLED IN EACH AREA FROM DIFFERENT HABITATS (Cottus asper). HABITAT  AREA PRICKLED N M a  c  d  e  f  g  h  i  j  River  16 7  Lake  94 28 48$ . 100$ 100$ 94$ 94$ 86$ 57$ 53$ 89$ 35$  Brackish 15 3  56$.  ,-b  94$ 100% 100% 100% 88$ 50% 44$ 94$ 38$  0$ . 100$ 100$ 100$ 93$ 47$  7$  0$ 93$ 0$  Mean 76.4$ 75.6$ 54.0$  23 The preceding tables indicate differences i n p r i c k l i n g between habitats.  Six out of eight of the areas on r i v e r sculpins were more heavily-  p r i c k l e d than those on lake sculpins.  A l l but one of the zones on the  brackish sculpins are l e s s p r i c k l e d than those of the lake forms.  The  averages indicate that a much greater difference exists between the sculpins from brackish and those from freshwater habitats than between those from the two  freshwater habitats.  Table 4 shows that the Lake specimens are  p r i c k l e d over less of the body than the r i v e r specimens, while the bracki s h specimens are much l e s s prickled than either.  A large difference  between both lake and stream and the brackish sculpins i s that the bracki s h ones lack p r i c k l e s on the head, beside the rayed dorsal, and below the l a t e r a l l i n e on the caudal peduncle.  Robins (1954) found similar  differences i n Cottus carolinae which was  l e s s densely p r i c k l e d i n lakes  and most densely p r i c k l e d i n t o r r e n t i a l r i v e r s . Differences also exist i n the number of meristic parts i n specimens from streams and lakes.  Table 5 shows the differences i n dorsal spines  and rays, anal and pectoral rays, branchiostegals, and vertebrae, i n l a c ustrine and f l u v i a t i l e  populations.  TABLE 5 MERISTIC DIFFERENCES BETWEEN LAKE AND STREAM POPULATIONS OF COTTUS ASPER The mean of the number of parts i s followed by the sample size i n parentheses.  HABITAT  NO. DORSAL LOCALS • SPINES  Rivers  16  Lakes  94  . 9.08(83)  DORSAL" . RAYS 20.69(77)  ANAL RAYS 16.92(78)  8.93(217) 20.70(214) 16.60(204)  PECTORAL RAYS  VERT.  BRANCH  16.44(81)  26.00(101) 6.12(88)  16.59(203)  25.81(240) 6.30(181)  24 It v d l l be noticed that there is almost no difference i n the number of dorsal spines or rays between individuals from lakes and those from streams.  River forms do have more anal rays, few pectoral rays, more  vertebrae, and fewer branchiostegals.  River forms may possibly not  require as many branchiostegals to support their g i l l membranes.  Stronger  g i l l membranes might be required of lake forms which have to pump the s t i l l water through their g i l l s .  Aim (1952) found that heritable d i f -  ferences were present between lake and stream populations of Salmo trutta. It i s also possible that the differences between lake and stream sculpins are caused by differences i n developmental conditions, rather than environmental selection. Coastal and Non-coastal  populations  It w i l l be noted that the greatest morphological differences occurred between brackish and freshwater populations.  This classification of  environments i s very coarse, only separating those individuals living close to or i n brackish water and a l l interior forms.  Since great  climatic differences exist between the interior and the coast, large morphological differences might also be expected to exist.  Therefore, a  closer comparison between coastal and non-coastal individuals was made. Coastal specimens were arbitrarily designated as those 10 miles or less from the sea and non-coastal as those 10 to 65 miles.  In order to secure  a large enough sample, specimens from Oregon to Prince Rupert were i n cluded.  About, equal number in the two groups were chosen from different  25 latitudes.  Table 6 below gives differences i n p r i c k l i n g .  As differences  between the two groups were very small i n b and c, these are not tabled. TABLE 6 PERCENT OF INDIVIDUALS PRICKLED IN DIFFERENT AREAS OF THE BODY FROM COASTAL AND NON-COASTAL POPULATIONS ( i n Cottus asper)  HABITAT  AREA PRICKLED a  d  e  f  g  h  i  j  Mean  Coastal  (52)  0$ 83$ 77$ 35$ 29$ 23$ 63$ 13$  Noncoastal  (35)  69$  91$  94$  91$  77$  86$  91$  77$  40.3$ 84.5$  Sculpins l i v i n g near the sea are evidently l e s s commonly prickled i n several body areas than sculpins l i v i n g away from the sea. This i s highly s i g n i f i c a n t s t a t i s t i c a l l y .  The p r i c k l e s were also observed to be  closer together i n the non-coastal forms.  P r o b a b i l i t i e s o f the s i g n i f i -  cance of difference of p r i c k l i n g i n d i f f e r e n t areas i s given below. Area a d  e f  P  Area  <.001 .2-.1 .05-.01 <.001  g h  i  P  <.C01 <.001 ,01-.001  Meristic differences between coastal and non-coastal populations of the p r i c k l y sculpin were also analyzed. table.  Data i s presented i n the following  26 TABLE 7 FREQUENCY DISTRIBUTION OF MERISTICS OF COASTAL AND COTTUS ASPER LOCAL  DORSAL SPINES 8  9 10  DORSAL RAYS  19 20 21 22 23  NON-COASTAL  ANAL RAYS  PECTORAL RAYS  VERTEBRAE  15 16 17 18  15 16 17  24 25 26 27 28  12 49 19  Coastal  4 69  7  2 22 47  7  1  0 14 50 16  NonCoastal  10 53  5  3 15 33 17  0  3  9 43 12  2 23 42  1 11 55 14  0  0  2  2 28 32  Chi square t e s t s showed that the p r o b a b i l i t y that the differences were due to chance i n dorsal spines was 0.2-0.1; i n dorsal rays, .05-.01; i n pectoral rays,  .001; and vertebrae,  -.001.  of anal ray counts they were not tested. and non-coastal populations  Because of the s i m i l a r i t y  The differences between coastal  i n dorsal rays, p e c t o r a l rays and vertebrae  are too great to be attributed to change. It has been shown that differences i n extent and i n t e n s i t y of p r i c k l i n g and i n numbers of dorsal rays, pectoral rays and vertebrae, between coastal and non-coastal p r i c k l y sculpins are s i g n i f i c a n t . What has caused these differences? answered.  B i o l o g i c a l data must be considered  before t h i s can be  According to Shapovalov and Taft (1954), p r i c k l y sculpins  migrated downstream to spawn through a counting fence close to the  sea  at Waddell Creek, C a l i f o r n i a . Sumner (1952) reports that Cottus asper were caught i n t h e i r downstream trap, which was tidewater,  j u s t below the head of  i n spring and early summer - the spawning period at Jewell  Creek, Oregon.  Hunter (pers.comm.) states that Cottus asper moves i n t o  the i n t e r t i d a l regions to spawn at Hooknose Creek, Port John, B.C.  This  27  information would indicate that coastal populations move down at least to within tidal influence to spawn. Often salt water, because of i t s greater density, moves i n under fresh water i n the intertidal zones of rivers.  It is thus possible that the eggs of coastal populations are  subject to brackish water.  On the other hand, i t i s unlikely that inland  sculpins would migrate long distances to the coast to spawn, and i t i s known that populations 50 miles from the sea spawn i n fresh water. Two possible explanations exist for the morphological differences. Firstly, the differences could be caused by the environment.  Salinity  differences during development may exist and these could modify meristics. Possibly temperature differences also exist. could be heritable. would also  expect  Secondly, the differences  Coastal forms migrate downstream to the sea.  One  several necessary adaptions to accompany this behaviour.  Physiological adaptions would be necessary i n the parents, fry and eggs to withstand the salinity.  Behaviour patters allowing return of the  adults and fry upstream would also be required.  These differences i n  spawning habit would also produce isolation which would permit genetic selection to take place and further differences to be developed. The threespined stickleback^ Gasterosteus aculeatus, has been found to have marine and inland populations with physiological, behavioral and morphological differences.  A l l these items would tend to suggest that Cottus asper  also has two genetically different forms, a brackish, lightly prickled one with fewer dorsal and pectoral rays and vertebrae, and an inland freshwater form.  As the morphological differences overlap i t i s unlikely that  they are. completely reproductively isolated.  28 Altitude A l l specimens for which altitude information was available were grouped under the categories: 0 feet (above sealevel), 200 feet, 1000 feet, 2000 feet, 3000 feet, and 4000 feet above sealevel.  The means and sample  sizes of the counts are presented i n Table 9, below. TABLE 9 RELATION OF ALTITUDE TO MERISTICS IN COTTUS ASPER Mean i s followed by sample size i n parentheses. DORSAL SPINES  DORSAL RAYS  ANAL RAYS  PECTORAL RAYS  VERTEBRAE  0»  8.97(36)  20.81(37)  17.00(36)  16.19(36)  26.29(31)  -200?'  9.00(18)  20.77(18)  17.12(17)  16.36(19)  26.26(19)  -1000'  9.10(10)  20.78(9)  16.82(11)  16.54(11)  25.92(13)  -2000'  8.89(29)  20.54(26)  16.56(32)  16.78(28)  25.27(33)  -3000'  9.14(69)  20.30(70)  16.54(61)  16.49(69)  25.14(69)  -4000'  8.76(34)  21.18(33)  16.76(34)  17.03(34)  25.84(33)  ALTITUDE  Altitude would appear from Table 9, to have a considerable effect upon meristics.  The average number of caudal vertebrae, dorsaland anal  rays behave similarly and decrease with increasing altitude up to 4000 feet, above which they increase.  Pectoral rays, on the other hand, tend  to show a positive increase with altitude, varying irregularly from one level to the next. The correlation with altitude may be spurious. However, temperature tends to decrease with altitude at an average rate of 3«3°F. per 1000 feet  29 (6°C. per 1000 m.).  ^he i n t e n s i t y of i n s o l a t i o n increases with a l t i t u d e .  Changes i n the components o f l i g h t also take place, with u l t r a v i o l e t and i n f r a r e d i n t e n s i t y increasing upward.  The differences i n meristics at  d i f f e r e n t a l t i t u d e s could be attributed to developmental or selective effects of these factors. Temperature Temperature has been shown experimentally t o modify meristic characters.  I t was decided to test i t s e f f e c t i n nature.  Unfortunately temper-  ature data are not available i n the most desireable form f o r correlation. Ideally spring temperatures - those during spawning times, would be the most l o g i c a l to correlate with meristics. isotherm maps are July or January.  However, the only available  July was chosen as the most suitable.  I t i s assumed that July temperatures are related to those i n the spring and that there i s a d i r e c t r e l a t i o n between a i r temperature and water temperature.  Table 10 gives mean July temperature and the means o f vertebrae  and f i n ray counts. TABLE 10 INFLUENCE OF TEMPERATURE ON MERISTICS Mean July Temperature, meristic mean and sample size ( i n parentheses) of B.C. Cottus asper AVERAGE JULY ISOTHERM DEGREES F. 70° +  8.87(31)  70°.-  DORSAL C " . DORSAL SPINES RAYS  ANAL RAYS  PECTORAL RAYS  VERTEBRAE  20.41(32)  16.56(32)  16.81(27)  25.28(29)  8.92(12)  21.00(12)  16.85(13)  16.75(12)  25.93(14)  65° -  8.94(140)  20.89(134)  16.98(130)  16.54(133)  26.21(131)  60° - '  9.15(118)  20.48(115)  16.74(111)  16.32(117)  25.59(121)  55° -  8.86(43)  20.93(42)  16.73(37)  16.89(38)  25.64(50)  30 The above data shows an increase i n dorsal spines with increase in temperature, except at the lowest temperature. an opposite relationship. mediate temperatures.  Rectoralsrays show  Vertebrae and anal rays are highest at inter-  V-shaped relationships to temperature were found  i n other species by Lindsey (1952) and Taning (1952).  Although several  of the differences are probably statistically different, no simple pattern i s apparent. Latitude Below i s a table showing how ray and vertebrae counts change with latitude from California to British Columbia. . Counts were taken from Snyder, (1905), 1908 and 1914), Rutter,^ (1908), Gilbert and Evermann (1895), Gilbert (1893) and Evermann and Goldsborough (1907).  Vertebral  means for Washington, Oregon and California were taken from Hubbs and Schultz (1932).  31 TABLE 11 LATITUDINAL VARIATION IN FIN RAY AND VERTEBRAL COUNTS, COTTUS ASPER Means and sample sizes  38°N  DORSAL SPINES 8.34(59)  . DORSAL ANAL PECTORAL VERTEBRAE RAYS RAYS RAYS 19.78(59) 16.36(59) 16.05(59)  40  8.70(20)  19.80(20)  42  8.73(49)  20.34(50)  44  8.98(46)  LATITUDE  16.67(20) 16.1 (10) 25.30(59) (California) 16.78(49) 15.80(44)  20.98(46) 17.20(46) 16.33(46) 26.06 (Oregon) 9.03(29) 21.04(28) 17.14(28) 15.89(19)  >  46 48  8.92(25)  20.40(25) 16.72(25) 15.53(15)  50  26.00 (Washington) 8.84(121) 20.88(205) 16.83(199) 16.69(205) 26.01(208)  52  8.86(29)  20.75(28) 16.77(30)  54  9.15(41) 20.48(44)  56  9.11(71)  58  9.0 (4) 22.2 (4)  16.86(28) 25.77(26)  16.63(43)' 16.95(39) 25.49(57)  20.23(60) 16.68(65) 16.44(73) 25.50(64) 17.5 (4)  16.5 (4)  26.8 (4)  Table 11 shows a tendency towards an increase in dorsal spines towards the north.  Large differences at different latitudes occur i n  pectoral rays but the oscillations are so great that the tendency to increase northward i s probably not significant.  In caudal vertebrae,  anal rays, and dorsal rays, the highest values are found at intermediate latitudes. Correlations Between Parts In comparisons between lake and river populations, and between populations from different temperatures, altitudes and latitudes, i t w i l l  32 have been noticed that some characters displayed similar reactions. Generally dorsal and anal rays responded "similarly, and-usually these two responded like vertebrae.  Pectoral and dorsal spines responded  differently from each other and from the preceding characters.Because of their morphological relationships, one would expect similar reactions from dorsal and anal rays and vertebrae, and dissimilar reactions between these and pectoral and dorsal fins.  The dorsal and anal rays are each, through  their basals, associated with the caudal vertebrae. and dorsal spines bear no such relationship.  The pectoral rays  To determine i f correlation  existed between the vertebrae and other characters, correlation tests were performed from a random sample of 24 collections of Cottus asper. The correlation coefficients (r), sample sizes (n) and probabilities (p) follow. Correlation dorsal spines x vertebrae  r  sample size  p  -.00956  188  ^.05  dorsal rays x vertebrae  .278  187  <C.01  anal rays x vertebrae  .172  179  pectoral rays x vertebrae  .0332  180  .05-.01 >.05  The above indicates that there i s l i t t l e relationship between dorsal spines and vertebrae and between pectoral rays and vertebrae.  A significant  positive relationship exists between the number of dorsal rays and the number of vertebrae, and between the number of anal rays and the number of vertebrae.  In other words, when a high caudal vertebrae count i s found,  a high dorsal.or anal ray count can usually be expected.  33 The association between anal rays and vertebrae, and between dorsal rays and vertebrae could be explained by gene linkage, or by vertebral influence on the number of rays i n development by similar effects of environmental factors on these characters. Comparative Variability of Characters. It i s convenient i n taxonomy to knovi which characters are the most variable.  The standard deviation gives a measure of the variability of  measurements and counts.  The standard deviation (for a l l B.C. Cottus  • asper) of dorsal spines i s .508, for dorsal rays .704, for anal rays i s .722, for pectoral rays i s .686, principal caudal rays .208 and for vertebrae .729.  The size of the standard deviation depends upon the size of  the mean, however. A comparable measure of dispersion i s obtained i f one multiplies the standard deviation by 100 and divides by the mean. This i s called the coefficient of variation.  The coefficient of variation for  dorsal rays i s 5.66$, for anal rays 3.39$, pectoral rays 4.14$, vertebrae 2.8$ and caudal rays 1.73$. Variability differences might be allotted to two causes.  One, that  organs developing' at a later period might be subjected to more environmental changes.  Two, the degree of constancy i s genetic. Here, the low  variability of some characters i s advantageous and has been selected for. Selection could make characters less variable by favouring development of the character at an earlier stage i n morphogenesis. Vertebrae probably develop earliest of meristic characters.  The  probable order of development of rays in.Cottus bairdi kumlieni (Marie Fish  34 1932) i s f i r s t the caudal, then the pectoral, anal, and second dorsal, and lastly the f i r s t dorsal.  This bears some relationship to the variability  of the parts, caudal rays being less variable than vertebrae, than dorsal rays, than pectoral rays, than anal rays, than dorsal spines i n Cottus asper.  The characters,.which develop earliest, assuming same developmental  sequence, are usually less variable.  Caudal rays and vertebrae which  develop earliest have the lowest variability.  It i s possible that dorsal  rays (arid not pectoral rays) are less variable than their developmental order would suggest because they are partly determined by the number of vertebrae which have preceded them. It i s also interesting to note that the caudal rays and vertebrae which are probably most important i n locomotion develop earliest and are least variable.  The spinous dorsal f i n , which probably has mainly a  behavioral function, develops last and i s the most variable. Year Class Variation No comparisons were made of year classes.  Northcote (1950) found  no difference between year classes zero and one i n dorsal spines and rays. A significant difference was found i n the number of anal rays. Sex Differences Northcote (1950) found no significant differences in dorsal spines, dorsal rays, and anal rays between males and females i n Cottus asper. DISTINGUISHING CHARACTERISTICS The prickly sculpin i s distinguished from a l l other B.C. forms by i t s complete lateral line, palatine teeth, single symphysial pore, 24-28  35 caudal vertebrae and distinct round black spot i n the posterior part of the spinous dorsal f i n .  36 Cottus cognatus Richardson I836  slimy sculpin (common sculpin,  Figure 10  mottled sculpin)  Synonymy Synonyms of eastern species may be obtained from Robins (1954).  See  also discussion i n text. DESCRIPTION Color Highly mottled grey-yellow coloration. 'Frequently orange flashes on lower flanks and under pectorals.  Remainder underparts white, except  for fine speckles on chin. Three or sometimes two mottled saddles under second dorsal. forming bars.  Second dorsal, caudal and pectoral with bands on rays The spinous dorsal of male i n spawning season dark to black,  particularly anteriorly and posteriorly, with broad orange edge. Male generally dark a l l over i n spawning season.  Dark patch beneath eye and  between eye and preopercle.(see Fig. 10). Morphology Maximum size i n British Columbia 120 mm.  Head small, 3-0-3.9 into  standard length; mouth small. Caudal peduncle deep, 3.2-4*4 i n head, usually 3.5-4.2. Posterior nostrils not tubular. A i papilla begins n a  to be longer i n male after a total length of about 60 mm., i t i s twice as long as female's - about 2 mm.  until at 80  It has a long flat  "V"-  shape i n the male while i n the female i t forms a small round extension. One, two or three preopercular spines may be present. stricted to a weak patch i n the a x i l .  Prickles are re-  The prickles are usually of i n -  tensity 1 above the lateral line and of 1 or 2 below.  The number of  mm.  37 p r i c k l e s above the l a t e r a l l i n e varies from 0 to 5, u s u a l l y 1 or 2, and v a r i e s from 0 to 86 below, usually about 40 to 50. shaft i s equal or longer than the length of the base.  The p r i c k l e The base of the  p r i c k l e i s oval (see F i g . 3). The skin i s slippery, hence the name slimy. Two pores are present on the t i p o f the chin, one on either side of the symphysis. Usually ( i n 46 specimens) there i s only one spine on the f i r s t dorsal basal, sometimes (5) there are two.  Often but one ray s i t s on the l a s t  anal basal or one t i n y ray i s bound to the l a r g e r so as only one i s d i s cernable i n the uncleared f i s h .  This i s not found i n other B.C. sculpins.  The .number of ventral f i n rays varies from three to four.  The l a t e r a l  line i s always incomplete and usually ends before the second t h i r d of the rayed d o r s a l .  I t usually contains 18-22 pores (rarely 12-25) i n specimens  over 60 mm. t o t a l length. DISTRIBUTION Cottus cpgnatus i s the most widely d i s t r i b u t e d of North American freshwater sculpins (see d i s t r i b u t i o n , F i g . 8). I t occurs on the eastern seaboard as f a r sbuth as V i r g i n i a , i n the Labrador Peninsula, the Great Lakes, i n northeastern Iowa and Minnesota.  I t i s apparently absent from most of  the Saskatchewan system, but i s present i n the North West T e r r i t o r i e s and Alaska from the A r c t i c Ocean to Kenai Peninsula.  In B r i t i s h Columbia i t  occurs i n the Yukon, Stikine, Mackenzie, Fraser and Columbia River systems. D i s t r i b u t i o n records were obtained from Eddy.and Surber (1947), Livingston (1952), Hubbs and Laglar (1949), Dymond (1947), Walters (1955), Iindsey (1956), C a r l and Clemens (1953), M i l l e r and Paetz (1953), Rawson (1951),  38 and the museum specimens of the Institute of Fisheries. GEOGRAPHICAL VARIATION Geographic variation of Cottus cognatus was studied only i n relation to latitude and river systems. Latitudinal variation Table 12 presents data showing variation associated with latitude. Two sets of data are presented for 70°.  The sample of five i s from  museum samples from the Colville River system, Alaska, the second sample of 12 is taken from Walters (1955).  The remainder of specimens are from  collections i n the Institute of Fisheries Museum. TABLE 12 LATITUDINAL VARIATION IN COTTUS COGNATUS Mean and sample size (in parentheses) LATITUDE DORSAL SPINES  DORSAL RAYS  ANAL RAYS  PECTORAL RAYS  VERTEBRAE  50°N.  8.53(51) 16.65(51) 11.82(50) 13.92(49) 22.56(45)  52  8.18(11) 17.00(11) 11.80(10) 14.11(9)  54  8.61(18) 17.22(18) 11.56(18) 14.12(17) 22.71(14)  56  8.24(25) 16.44(25) 10.96(25) 14.08(25) 22.35(23)  58  8.35(17) 16.83(18) 10.67(18) 13.67(18) 22.61(18)  60  8.26(34) 26.62(34) 10.57(35) 13.86(36) 22.04(23)  70  8.2 (4)  70  8.3 (12) 15.5 (12) 11.3 (12) 13.3 (13) 21.7 (9)  15.6 (5)  10.4 (5)  21.90(10)  13.4 (5)  The foregcmg table demonstrates several clines.  An unidirectional  cline i s found i n anal rays i n which the number of parts decreases  39 towards the north.  The two samples at 70° confirm one another except .  i n the anal ray count where a difference of nearly a whole ray i s found. Walters' anal ray count i s the only one which does not f i t into the c l i n e . The remainder of the counts, dorsal spines, d o r s a l rays, pectoral rays and vertebrae a l l tend to show a double c l i n e , decreasing away from 54°.  The  condition over most of the range (from 54-70°) i s a decrease northward. The significance of the double c l i n e s i s discussed under r i v e r systems. River System Variation The greatest differences i n meristics between l a t i t u d e s occurred from 54° to 56° (Table 12). Fraser Rivers.  These l a t i t u d e s coincide with the Peace and  To determine the amount of v a r i a t i o n a t t r i b u t a b l e to  r i v e r systems the data were r e c l a s s i f i e d .  The mean dorsal spine, dorsal,  anal, v e n t r a l and pectoral ray counts for the major of B.C. are given i n F i g . 2. Lindsey (1956) noticed that Peace River forms had only four ventral rays, unlike those of more southerly B.C. specimens which had three to four.  Figure 2 shows that the means of v e n t r a l ray counts of the lower  Peace (defined as below the Ne-parle-pas Rapids which are shown on :  Figure 2a) the Liard and the Stikine are. consistently higher than those of the upper Peace, Fraser and Columbia Rivers. are probably impassable to f i s h .  The Ne-parle-pas Rapids  It i s interesting to note that Cottus.  r i c e i , Percopsis omiscomaycush, Stizostedion vitreum and Platygobio g r a c i l i s have not yet been recorded i n the upper Peace, although they are found i n the lower Peace and L i a r d .  The lower Peace, Liard and Stikine  40 specimens (referred hereafter as Northern) never have three v e n t r a l rays, while the upper Peace, Fraser and Columbia (hereafter referred to as Southern) frequently have three v e n t r a l rays. mens have three ventral rays.  None of the Alaskan speci-  Figure 2 shows that the greatest difference  between adjoining systems i n many meristics occurs between the upper and lower Peace.  Frequently the differences are smaller within the Southern  or Northern classes than between them.  The fact t h a t the upper and lower  Peace are not c l i m a t i c a l l y d i f f e r e n t would suggest the differences between them are not the result of environmental influences.  The small  sample size of the lower Peace c o l l e c t i o n should be noted.  The constant  presence of a fourth v e n t r a l ray, however, would confirm the low a l l i a n c e of the lower Peace to the Northern. Body proportions were also examined i n northwestern specimens af Cottus cognatus.  Following i s a l i s t of the means of the head/caudal peduncle  r a t i o i n Cottus cognatus from the d i f f e r e n t r i v e r systems. Mean  Range  Alaska Liard River Lower Peace  4.13  3.8-4.8 3.4-4.7 3.6-4«4  7 18 10  Upper Peace Fraser River Columbia River  3.63 3.3-4.1 3.59 . 2.9-4-3 3.70 3.4-4-2  20 17 16  3.93 3-89  Sample  It w i l l be seen again that there "is a break between the upper and lower Peace and that t h i s difference is.greater than that, between the upper Peace and the Fraser.  In f a c t , the mean of the lower Peace i s  closer to that of Alaska than i t i s to the upper Peace.  Chi square tests  show that the difference between the upper and lower Peace i s s i g n i f i c a n t  Stikine River  «13 i i i i £ 27  Liard River  9 13  • 13  •3  •  \  27  '  ' ,:  14  V*5  27 \  \  '.'  •  /  /  \  \  .  *  Lower Peace River  & 10 O 17  N  N  N  \  6v 38  Columbia River  O  8  16  Dorsal Rays  17  P  O 38  9 19  20  ?37  <3 32  i  d 75  6 78 9  •8  10  19  *038  76  Dorsal Spines  O,  .20 N  Fraser River  *  Ne-parle-pas Rapids O  Upper Peace River  110  11  Anal Rays  12  67  <>66 3  Ventral Rays  4  13.5 14.5 Pectoral Rays  NUMBER OF RAYS Number beside point is sample size  FIGURE 2.  Means of Fin Ray Counts i n Cottus cognatus from Different River Systems  Figure 2a.  Probable redispersal of Cottus cognatus from two centres following the Wisconsin glaciation.  ^  2  (p (.05) while that between the upper Peace and the Fraser i s not significant. What accounts for the dissimilarities of the adjacent upper and lower Peace and the similarities within the Northern and Southern groups? Glacial history provides a good e:xplanation of these similarities and differences.  During the last glacial period, parts of Alaska were icefree  (Walters 1955), probably permitting cognatus to survive there.  Walters  considers cognatus to have been present i n Alaska since the Bering land bridge.  Probably cognatus was also present south of the ice sheet.  Pro-  gression of the ice sheet would have resulted i n the southward displacement of these sculpins until they were present i n the Columbia River system. As the ice moved no farther south than about 49°, the slimy sculpin could well have survived the duration of the glacial period i n the Columbia system.  When the glaciers retreated, cognatus might well have followed  northward.  It is l i k e l y that i n the wake of the glacier the upper bend of  the Fraser and the Big Bend of the Columbia were connected.  Dispersion  could thus have occurred into the upper Fraser, where the species exists today (see distribution map).  As no collections have been made i n the  bend of the Fraser i t i s unknown whether present day distribution would support the entrance of cognatus into the Fraser from the Columbia.  On  the basis of known distribution elsewhere, this i s apparently the only l i k e l y means of transmission between the two systems (see Figure 2a). From similarities between the upper Peace and the Fraser, i t would seem l i k e l y that Fraser cognatus repopulated the upper Peace.  Geological  43 evidence shows that the upper Fraser flowed into the upper Peace at the end of the last glaciation.  That such a transmission i s possible i s  demonstrated by the presence of Cottus asper i n the upper Peace, where i t s present restricted distribution strongly suggests entrance from the Fraser.  Probable movements of cognatus following glaciation i n B.C. are  given i n Figure 2a. Figure 2a also compares Stikine populations with other systems.  The  differences would indicate that the Stikine i s more dissimilar to the Fraser than to the Mackenzie. the Northern forms.  The Stikine has the high ventral f i n ray count of  It seems l i k e l y that Stikine populations originated  from headwater capture, probably from the Liard, the Stikine being very close to Dease Lake, or from the Yukon. The constancy of the ventral rays i n Alaskan derived types, the continuity of meristics and proportions i n the {Northern and i n the Southern groups, the sharp break between.the adjacent populations, and the absence of climatic isolines conforming with this distribution, a l l support the hypothesis of glacial segregation and subsequent redispersal from two sources.  "  Sex Differences The means and sample sizes of meristic counts for males and females are given i n Table 13, below. Fraser and Columbia.  The sample includes specimens from the Liard,  44 TABLE 13 SEX DIFFERENCES IN MERISTICS OF B.C. COTTUS COGNATUS SEX  D  D  x  A  2  P  VERTEBRAE  Male  8.46(26)  16.79(24)  11.42(26)  14.12(25)  22.38(21)  Female  8.44(27)  15.59(27)  11.52(27)  13.78(27)  22.56(23)  Chi square tests were performed on those characteristics showing the greatest difference, pectoral rays, dorsal rays and vertebrae. nificant differences were found.  No sig-  It i s possible that the variation from  different river systems obscured differences and that a larger or more homogeneous sample might reveal sexual dimorphism. The Systematic Position of Cottus philonips Eigenmann and Eigenmann In 1892 Eigenmann secured 17 specimens of Cottus i n the snow waters of the Kicking Horse River (Columbia system) i n southeastern B.C. were named i n the same year as Cottus philonips.  These  With further knowledge  of the distribution and variability of Cottus cognatus i t now appears that philonips i s synonomous with cognatus.  The following table compares de-  scriptions of 'philonips with measurements of B.C. cognatus. TABLE 14 ;./.:;  Cottus philonips  Cottus cognatus 3-0-4.0  Head into standard length  4-4^ 3.8  Depth  6.0  Dorsal spines  8-9  8-9 (rarely 7-10)  Dorsal rays  16-18  16-18  Anal rays  11-13  10-13  Palatine teeth  Absent  Absent  Preopercular  1  1-3  spines  or  -4.6-6.2  (15-19)  45 The description of color i n Eigenmann (1892) and Jordan and Evermann (1898) agrees very well with that of cognatus.  According to the key i n  Jordan and Evermann the skin i s smooth or nearly so and Carl and Clemens describe the skin as without prickles.  Specimens of cognatus from the  Flathead River (Columbia system) of southeastern B.C. have been found to lack prickles and i t i s common to have the prickles reduced to less than a dozen.  The prickling of philonips i s not, therefore, outside the range  of that of cognatus.  The position of the t i p of the maxilla, t i p of the  pectoral and of the anus mentioned i n the original description do not serve to differentiate the two.  The last six of the characters i n the  preceding table do not show reason for differentiation. Eigenmann's statement about the head i s the only one not i n agreement with cognatus.  Eigenmann (1892) states, "Head proportionately longer i n  adult, about 4^-4 in- head."  Usually head proportion i s indicated by  how many times i t enters standard length. Eigenmann writes as i f some part, not mentioned, enters the length of head 4^-4 times, which i s i l logical.  Standard length does not enter 4^-4 times into tne?head length;  the reverse would be true.  Jordan and Evermann (1898) describe one of  the type specimens having head length such that the standard length i s 3.8 times i t s length. Their key;states the head of philonips enters 3s~4 times i n standard length, so they must have been sure of this character. Although f a i r l y extensive collections have been made i n the upper Columbia River, and one i n Emerald Lake near the type locality (about 5 miles from i t ) no sculpins have been found having 4 to 4^ into standard length.  46 For the above reasons 1 believe that Eigenmann was describing the number of times some other part, such as eye, enters the head, or seme other measure of the head (snout to preopercle) or made an error i n describing the head. Hence, because no other differences have been found, I would consider philonips synonomous witb. cognatus. has priority.  ^ottus cognatus  In the event that philonips should prove to be a distinct  form, i t w i l l require a new name for reasons given by Hubbs and Schultz (1932).  47 Cottus N. S£.  shorthead sculpin  Figure 10 DESCRIPTION Color Light clay colored background with dark mottlings. mottled saddles under second dorsal.  Three light  Chin evenly speckled. Pectoral,  dorsal, and caudal fins with mottled crossbars.  Dark medium band i n  f i r s t dorsal f i n , more intense anteriorly and posteriorly. light i n preserved males.  Edge of f i n  Trapezoidal bar beneath eye and stripe passing  backwards from eye to preopercle.  Orange flash may be present on flank.  Chin evenly speckled. Morphology Total length up to 105 nm.  B  ody stouter than other B.C. species.  Head short, round from above, 3.2 - 3.7 times into standard length of B.C. specimens. head. teeth.  Tail short.  Caudal peduncle deep, 3.2 - 3.6 times into  Palatine teeth present, but weak, not i n contact with vomerine Posterior nostrils g'emitubular.  Anal papilla longer i n male.  Preopercular spine at corner of preopercle with one below and sometimes a small projection underneath (2 below i n some U.S. specimens according to pers. comm. from Bailey). or absent.  Prickles i n weak patch behind pectoral fins  Two sympheseal pores are present.  One spine on the f i r s t dorsal basal i n a l l five specimens examined. Inter-dorsal spines and rays each on own basal with no empty inter-  48 dorsal basals i n those examined.  Ventral fins 14 i n a l l examined, ex-  cept one having. 5 rays on one side.  Lateral line extends up to 2/3  of the way past the origin of second dorsal and contains 20 - 24 pores i n specimens over 60  mm.  About a dozen of this species were collected i n the Flathead River of the Columbia system i n southeastern British Columbia, along with Cottus cognatus (which was more numerous).  -*-t was designated as  Cottus  bairdi punctulatus (Gill) with which i t agreed i n several characters and disagreed i n others, semiscaber.  It also showed some similarities to Cottus bairdi  Several specimens were sent to Dr. R.M.Bailey of the Univer-  sity of Michigan who has been working on the group for several years. Dr. Bailey informs me that these specimens were of a new species he had collected i n Idaho, northeastern Oregon and eastern Washington. He i n tends to give a brief synopsis of American representatives of Cottus within the year, i n which he w i l l name the new species.  Because of i t s  small head, i t w i l l be referred to as the shorthead sculpin i n this thesis. As the shorthead sculpin is present i n only one river system i n British Columbia and as no other published data exist oh i t , no discussion of i t s variation w i l l be given. DISTRIBUTION The shorthead sculpin occurs i n the Salmon River i n Idaho, i n the Columbia system i n northeastern Oregon and i n eastern Washington. British Columbia i t has been found only in the Flathead system.  In  49 DISTINGUISHING CHARACTERISTICS The shorthead sculpin is distinguished by i t s 2 chin pores, incomplete lateral line ending before the termination of the second dorsal, palatine teeth and i t s short head and one or two preopercular spines. It i s not a highly differentiated form and further investigation may indicate i t to be a coldwater variant of Cottus bairdi or hubbsi.  50 Cottus hubbsi Bailey and Dimick 1949  Columbia sculpin  Figure 10 Synonomies The nomenclators stated that Cottus hubbsi has been confused with Cottus rhotheus.  Literature references were not given, however.  DESCRIPTION Color Light to dark brown with dark markings. second dorsal f i n . broad dark bands.  Three dark saddles under the  Rays of dorsal, caudal, pectoral and often anal with Dorsal f i n in breeding male possesses a dark median  band; i n preserved fish the edge i s devoid of pigment, but possibly i t may be colored i n fresh specimens.  Orange flash on flanks.  In non-  breeding males and females the median band i s reduced to dark areas i n the anterior and posterior parts of the f i n . abdomen i s sprinkled with fine black spots.  The chin and less so the Two eye bars, similar to  those i n Cottus asper, are present. Morphology The maximum size yet found i s 122 mm.  The head and mouth are of  medium size, the former entering standard length about 2.9 to 3«2 times. The chin i s unwrinkled.  The caudal peduncle i s of medium depth, entering  the head 3.7 to 4.6 times, entering the standard length about .072 to .085 times.  The strong palatine teeth are separated from the vomerine  patch of teeth. Posterior nostrils semitubular.  Anal papilla longer i n  51 adult male.  Three preopercular spines present. Prickles usually present  behind pectoral f i n , stronger below lateral line.  Occasionally prickles  extend onto i n front of the dorsal, beside the rayed dorsal or onto the dorsal surface of the caudal peduncle. The unprickled portion of the skin i s slippery.  Each prickle has a short shaft about equal to the length  of the round or oval base. Of 40 specimens, 39 had one spine on the f i r s t dorsal basal and one had two spines.  Twice as many individuals (26/13) had the lastsspine and  f i r s t ray on their own basal as had an empty basal.  The lateral line i s  nearly always incomplete, missing on the caudal peduncle-.. It contains about 28 to 36 pores, rarely 23 to 38 i n specimens over 60 mm. DISTRIBUTION Cottus hubbsi i s limited', as far as i s known, to the Columbia River system.  It i s found i n Idaho, Washington and British Columbia, -*-ts  distribution i n B.C. may be seen on Figure 8. Distribution i n U.S.A. i s given by Bailey and Dimick (1949). GEOGRAPHIC VARIATION To determine i f latitudinal changes exist, Bailey and Dimick"s data from Washington and Idaho were compared with British Columbia material. Dorsal spines, dorsal rays, anal rays and pectoral ray counts from if.S.A. and Canada are contrasted i n Table 16.  52 TABLE 16 MERISTIC DIFFERENCES IN CANADIAN AND AMERICAN COTTUS HUBBSI LOCAL  D 7  British Columbia Washington & Idaho  D  x  '8 8 13 13 27  A  2  P  16  17  18  11  12  13  14  13  14  15  16  1 2  16 30  4 8  4  10 19  10 15  1 1  1  5 9  21 27  16 3  Chi square tests were applied on the two characters which appeared most different, anal and pectoral rays.  The difference between anal rays  was not found to be significantly different, (p=0.3-0.5), while that between pectoral rays was significant, (p=0.01-0.001).  This would indicate  that the greater number of individuals with higher pectoral rays counts in U.S.A. i s significant.  Bailey and Dimick included counts of both  right and l e f t pectoral rays, while mine included only those of the l e f t . It i s possible the difference i s attributable to bilateral differences. DISTINGUISHING CHARACTERISTICS The Columbia sculpin i s distinguished by 2 symphisial pores, evenly speckled chin, palatine teeth, axillery prickles and lateral line extending past the rayed dorsal.  53 Cottus fhotheus (Rosa Smith) 1882  the torrent sculpin  Figure 11 Synonomy Uranidea rhothea Rosa Smith (Mrs. Eigenmann), Proc. U.S.Nat.Mus.5:347, 1882 Spokane Falls, Washington; Jordan and Gilbert, Synopsis, 1883. Cottus rhotheus (Rosa Smith) Gilbert and Evermann 1895; Syder 1908a. Cottus rhothea (Rosa Smith) Jordan, Evermann and Clark 1930? Dymond 1935. DESCRIPTION Color Color grey brown with black specklings. Two sharp saddles sharply outlined and angled forward from underneath the second dorsal; occasionally small saddle- between. Orange flashes often present on the lower flank and between the pectorals.  Dorsal fins, caudal f i n and often anal f i n  with .bars on rays forming bands. bands.  Speckles on the pectorals may form vague  The rim of the spinous dorsal f i n i s thickened and colored orange  i n the spawning male; the base may be dark. species i s strongly mottled (see Figure 11).  The chin, unlike other B.C. Often the ventral surface  of the body i s speckled. Morphology Total length up to 160 mm.  Head long and wide, entering 2.65-3.0  times into standard length. Mouth large, width about 5.7 times into total length (when about 42 mm long), largest of B.C. species (Northcote 1950).  Caudal peduncle narrow, depth contained 4.8 to 6.4 i n head.  Strong palatine teeth, band usually i n contact with the vomerine teeth.  54 Pyloric cacae 4-5. Posterior nostril semitubular. and narrow i n male, short and tubular i n female. spines'.  Anal papilla long Three preopercular  Strong prickles are usually found on the head, sides, beside  the dorsal fins, on the upper part of the caudal peduncle and beside the anal f i n .  Occasionally, according to Bailey and Dimick (1949)  the prickles are much reduced.  Each prickle has a large oval base  which i s equal to or greater than the height of the spine (see Figure 3). The proximal portion of the base i s usually serrated. pores are present.  Two symphysial  The skin of the lower mandible i s wrinkled.  Usually one spine i s found on the f i r s t dorsal basal.  The inter-  dorsal basal may be ray less (15 specimens) or occupies by a spine or ray (10).  The lateral line i s usually complete and often extends onto  the caudal f i n .  It i s usually complete on individuals over a total  length of 70 mm., and bears 32 to 38 pores.  (Several points of the  preceding description have been derived from Bailey and Dimick (1949).) DISTRIBUTION The torrent sculpin i s reportedly found i n British Columbia, Washington, Oregon and Idaho, i n the Columbia and Kootenay Rivers, and i n Puget Sound drainages Nehamlem River, Oregon. distribution given by Schultz and Delacy 1936.  This i s the  It is possible their  localities contain Cottus hubbsi with which C. rhotheus has been confused.  For this reason I have only given B.C. distributions, where i d -  entity i s certain, on Figure 8.  55 SEX DIFFERENCES The following table combines Northcote's (1950) and my data on sex differences i n Cottus rhotheus. TABLE 15 SEX DIFFERENCES IN COTTUS RHOTHEUS, A COMPARISON OF MERISTICS. SEX  D  l  D  7 8 9  14  Male  - 6 16  -  Female  2 9 23  15  2  P  A  2 16  17  6 13  2  8 17  6  11  12  13  4 17  1  12  22  1  16  21  7  7  2 11  14  15  -  Vertebrae 22 23 8  1  16 -  A chi square test on the largest difference between sexes i n the table, anal rays produced a chi square which was not significant. Northcote also found no significant difference between dorsal spines, dorsal rays, anal rays and caudal vertebrae between sexes. GEOGRAPHIC VARIATION Northcote (1950) found the difference i n dorsal rays between samples from both Idaho and the Columbia River and the Arrow Lakes was significantly different. was significant!  The increase i n vertebrae from Oregon to B.C.  Correlations between dorsal rays and dorsal spines and  between dorsal rays and anal rays were not found to be significantly  Bailey and Dimick (1949) state that Cottus rhotheus exhibits considerable geographic variation.  Specimens from coastal Washington and Oregon  were found by than to have a somewhat shorter head, the lateral line not extending onto the caudal f i n base, and the prickles on the body much  56 reduced or sometimes completely absent.  The last condition i s similar  to that found i n coastal populations of Cottus asper.  Cottus rhotheus  has not been recorded as entering brackish or salt water, however. DISTINGUISHING CHARACTERISTICS Cottus rhotheus i s distinguished by i t s 2 sharp dark dorsal saddles, i t s highly mottled chin, i t s strong palatine teeth which touch the vomers, and the two pores on the t i p of i t s chin.  57 Cottus aleuticus Gilbert 1893  Aleutian sculpin  Figure 9 Synonomy Uranidea microstoma Lockington, Proc. U.S.Nat.Mus., III, 58, 188Q, St.Paul, Kodiak Island; name preoccupied i n Cottus. Cottus aleuticus Gilbert, Rept. U.S.Fish.Com.,XIX, 418, 1893, streams at Unalaska; also i n Departure Bay, Vancouver Island. DESCRIPTION Color Color grey with dark blotches, underparts white. saddles under second dorsal.  Three mottled  Rays of dorsals, caudal, and pectorals cov-  ered with series of crossbars forming bands.  Male darker, nearly black,  with a broad orange band on edge on f i r s t dorsal f i n when spawning. covered evenly with fine speckles, unwrinkled.  Chin  Often orange splotch  at basd of pectoral f i n and white bar at end of second dorsal across top of caudal peduncle.  White v with base at front of dorsal with arms point-  ing forward, as"in asper but much more intense. Morphology Total length up to 115 nim.  Head and mouth small. Caudal peduncle  deep. o teeth on palatine bones. w  inclined posteriorly.  Posterior nostrils distinctly tubular,  Anal papilla longer i n male than i n female.  Only  one preopercular spine, at corner af preopercle. Prickles restricted to small area behind pectoral, occasionally absent.  Rarely a few weak prickles  above lateral line, usually restricted to below.  Prickles of distinctive  shape (see Figure 3), with long broad shaft and base which i s reduced to a slight enlargement on end of shaft.  Only one symphysial pore.  58 A l l forty-eight Aleutian sculpins examined possessed two spines on the f i r s t dorsal basal, the most constant species i n this regard.  Ten  of forty-six had an empty basal between the dorsal fins, the remainder bore one ray or one spine on the interdorsal basals. After a total length of 60 mm.  has been reached the lateral line i s complete, bearing 34-44  pores, usually 38. DISTRIBUTION The Aleutian sculpin occurs i n Pacific drainages from Carmel River, just south of Monteray Bay, California - 36° 50' N, to Unalaska, Alaska at the western t i p of- the Aleutian Peninsula, north to Kodiak Island and the Bering Sea - about 60° N (Wilimovsky 1954).  Although mainly coastal,  i t occurs as far inland as 300 miles i n the Skeena system.  See Figure 8  for distribution. GEOGRAPHIC VARIATION Coastal and Non-coastal As coastal population of Cottus aleuticus have shown downstream spawning migrations i n Waddell Creek, Californis (Shapovalov and Taft 1954) similar to those i n Cottus asper, i t might be expected that "coastal" groups exist.  Table 16^below, gives the counts for meristic characters  in Cottus aleuticus 10 miles and less from the sea and 10 to 50 miles from the sea.  59 TABLE 16 a COMPARISON OF MERISTICS OF COASTAL AND NON-COASTAL COTTUS ALEUTICUS LOCAL  D 8  Coastal NonCoastal  D  x  9  A  2  18 19  20  12 13  5 17  4  14  3  011  9 17  5  22  3  1  12  P 14 15  VERTEBRAE  13  14  15  16  12  7  0  1 4  8 15  2  0  9  1  3  12  2  2  24  25  26 27 9 1  2 17  Chi square tests applied, to the characters which showed signs of difference, vertebrae and pectoral rays.  The difference between the  pectoral rays yielded a probability of .05-.02, vertebrae .3-.2. Since only one character differs significantly and since one would expect several differences to arise i f separate populations existed, the differences could be attributed to environmental factors.  Data on 35 specimens indi-  cates no difference i n extent or degree of prickling. Latitudinal Variation Comparisons of meristics were made every 4°'  Hubbs and Schultz (1932)  give the data on number of vertebrae for California and Washington specimens . Table 17 below shows latitudinal variation of Cottus aleuticus. TABLE 17 LATITUDINAL VARIATION IN VERTEBRAE OF COTTUS ALEUTICUS Number of Caudal Vertebrae  Latitude  Mean  24  : > 25  26  27  57-60° N  1  6  11  2  25.70  53-56  -  2  7  7  26.31  57-52  1  11  32  5  25.84  Washington  1  12  25  5  25>79  California  1  5  5  —  25.36  3  60 Table 17 shows an obvious tendancy for vertebral means to increase northward.  A drop, which appears significant, occurs at 57-60°N. Un-  grouped data show this to take place starting at 56°. SEX DIFFERENCES Table 18 below compares the meristics of males and females TABLE 18 COMPARISON OF MERISTIC FREQUENCIES IN MALES AND FEMALES OF COTTUS ALEUTICUS SEX  D^ 8  Male  9  3 11  Female.10 25  I>  A  2  10  18 19  1 3 14  20  12 13  10  2  0  6  23  2  2 23  P 14 15  9  0  13  2  13  VERTEBRAE  14 15  2  5  3  29  4  16  24 25  4 6  1  1  26 27  1  9  4 10  Chi square tests were applied to the data which showed signs of differences - vertebrae, pectoral and anal rays. found significantly different.  Only pectoral rays were  The males had significantly more pectoral  rays, p.05-.02. The explanation of this might be found i n the behavior of the male.  The male i n Cottus gobio, the English sculpin, has been found  to fan the eggs with undulations of his pectoral fins. curs during incubation until just after hatching. been observed i n Cottus asper by the author.  This activity oc-  Similar behavior has  Possibly the increased  number of rays i s associated with egg-fanning activity i n Cottus aleuticus. It i s interesting to note that, although the differences were not s i g n i f i cant, more pectoral rays were found i n male Cottus cognatus and rhotheus. DISHNGUISHING CHARACTERISTICS Cottus aleuticus may be distinguished by i t s tubular nostrils, single preopercular spine, 24 to 27 caudal vertebrae and single symphysial pore.  3  61 Cottus r i c e i (Nelson)  1876  spoonhead sculpin  Figure 11 Synonomy Cottopsis r i c e i Nelson, Bull.ILl.Lab.Nat.Hist.,I, 40, 1876, Lake Michigan off Evanston. Uranidea pollicaris Jordan and Gilbert, Proc.U.S.Nat.Mus., V, 222, 1882, Lake Michigan off Racine, Wisconsin. Uranidea r i c e i Jordan and Gilbert, Bull.U.S.Nat.Mus., 16, 953, 1883 Uranidea spilota Jordan and Gilbert, Synopsis, 694, 1883, not of Cope. Uranidea r i c e i , Jordan and Gilbert, Synopsis, 953, 1883. Cottus pollicaris Jordan and Evermann, Bull.U.S.Nat.Mus., 47, 1954, 1898. Cottus r i c e i Jordan and Everman, Bull.U.S.Nat.Mus., 47, 1952, 1898. DESCRIPTION Color Light brown with dark markings.  Two to four dark saddles, usually  three, under second dorsal. Narrow bands on rays of dorsals, caudal and pectorals.  Chin evenly covered with fine speckles.  Morphology Head small, about 3*5 times into standard length. Mouth small, head wide, widest at preopercle where width equals length. Caudal peduncle narrow.  Chin wrinkled.  No teeth on palatines.  erior nostrils semitubular.  Four pyloric cacae.  Post-  Upper preopercular spine curved upwards and  inwards i n an arc resembling the horn of a bison. One to three, usually two, smaller spines below. Prickles highly variable, may cover whole body (even on head and abdomen) or be reduced orJabsent. individuals often have more preopercular spines. base which i s longer than the spine.  Strongly prickled  The prickle has an oval  The long base i s strongly serrate  on the side distant from the spine (see Figure 11).  One symphysial pore  62 i s present. Meristic variation i n Figure 7 includes specimens from over the whole North American range (other species counts just from B.C.). specimens had one spine on the f i r s t dorsal basal, two had two.  Twelve Out of  15 specimens one had three empty basals between the dorsals, one had two empty basals, four had one empty basal and i n six a l l the interdorsal basals were occupied by a spine or a ray. The l a t e r a l line i s usually complete at a total length of 55 mm.  When complete i t contains from  35 to 37 pores. DISTRIBUTION The spoonhead muddler i s found i n the Great Lakes system, i n James Bay drainages, i n the North Saskatchewan River, i n Lesser Slave Lake and tributaries, i n Lake Athabaska, i n Great Slave Lake, i n the Peace River and i n the Muskwa River of the Liard system (last two i n B.C.) and i n the main Mackenzie River to the delta.  The distribution map shows a div-  ided distribution, with no records from a l l of Manitoba and most of Saskatchewan.  It may be that insufficient collecting has been done i n  these areas. GEOGRAPHIC VARIATION As only two collections of Cottus r i c e i have been made i n British Columbia, the literature and museum collections from other locals have been relied on.  Table 19 shows latitudinal variation i n Cottus r i c e i  from southeast to northwestern North America.  Data from Lake Erie were  obtained from Marie Fish (1932), Lakes Michigan, Huron and Superior  63 from Hubbs (1919), Lake Wipigon Dymond (1926) and some Lake Michigan and the remainder from Institute of Fisheries material. Only about thirty specimens are involved i n Table 19. small sample size trends are apparent. northward.  Despite this  The number of anal rays decline  The pectoral and dorsal rays probably also decline northward,  while the dorsal spines perhaps increase northward. The distribution of Cottus r i c e i is,disjunct, a northwest and a southeast region being populated.  Significant differences probably  exist i n the characters of the two groups.  However, they should not be  given taxonomic status. Clinal groups, unless they contain sharp zones of change, should not be given subspecific or specific status. Bailey, Winn and Smith (1954) discuss the c l i n a l problem i n taxonomy. The distribution of ricei looks almost as i f the original distribution was continuous and had been cleaved by glaciation.- If this i s so, where did the northwestern group survive? i n Alaska (Walters 1955).  It i s not known to be present  It i s possible that the northwestern group  followed the glaciers southward, then north on glacial retreat.  This  does not explain the absence of an intermediate group, however.  It i s  possible that the spoonhead sculpin has remained undiscovered i n the intermediate regions.  TABLE 19 CHANGES IN THE MERISTICS OF COTTaS RICEI FROM SOUTHEAST TO NORTHWEST IN NORTH AMERICA. DORSAL SPINES DORSAL RAYS 7 Lake Erie Lake Huron and Lake Michigan  16 17 18 19  1 5 5  Lake Superior Lake Nipigon  8 9....10  •  ANAL RAYS 11 12 13 14  1 1  1  6  3  1 c c r  c  PECTORAL RAYS 15 16  14 15 16 17  1 1  3 7  1  1  c  c  VERTEBRAE 23 24 25  1 1  2  7  1  1  1  ON  North Saskatchewan 1  1  Peace River  1 1  1 1  Muskwa River  7 1  Lesser Slave Lake  2  Great Slave Lake  2  1  1  6  1 1 1 2  2  1  8 1  1 1  1 1  8 1  1  •"  1 4 5  2 1 1  1  1 1 2  1 1 1 1  p  65 COMPARISON OF SPECIES AND INTERSPECIFIC VARIATION RELATIONSHIPS OF SPECIES TO ONE ANOTHER The following briefly summarizes the closest relatives of a species, why and to which species i t i s most closely related. Casper seems to be most closely related to Cprinceps because of similarities i n vertebral counts, chin pores and the number of spines on the f i r s t basal of the spinous dorsal f i n . 6.cognatus appears to be most closely related to the shorthead sculpin and Chubbsi and other members of the bairdi group.  Sexual dimorphism,  coloration, vertebral counts and chin-pores relate the two.  C.aleuticus  resembles cognatus i n body proportions, dentition, coloration of spinous dorsal of spawning male and prickling.  Probably this resemblance i s  secondary - an example of the common convergent evolution i n the group. The shorthead sculpin resembles hubbsi and cognatus i n several respects. It differs from cognatus i n dentition, i n which i t resembles hubbsi.  The  opercular mandibular pores i n cognatus agree i n number and pattern with the shorthead and differ from hubbsi.  More study w i l l be required to det-  ermine the exact relationships. C.aleuticus bears many affinities with Cchamberlini and protrusus which are discussed i n Schultz and Spoor (1933) i n which reference protrusus was named:. The similarities are numerous and the differences few and i n vestigation might show synonomy. Crhotheus has many affinities with C.ricei.  Their wrinkled chin,  prickling and prickles, narrow caudal peduncle, wide f l a t head, preopercular  66 armature, complete lateral line and serai tubular nostrils are common features.  C.rhotheus i s distinct from r i c e i i n i t s fewer caudal verte-  brae (21-22 instead of 23-25); longer head and larger mouth, palatine teeth, 2 instead of 3 to 4 (rarely 2), saddles under the second dorsal, and two instead of one symphisial pore.  It i s possible that rhotheus  i s a modified r e l i c t of r i c e i from some past glaciation. C.rhotheus i s somewhat similar to C.carolinae i n mottling and wrinkling of the chin, speckling on the pectoral fins, and two sharp saddles under the second dorsal, i n having the vomerine and palatine teeth i n contact, and i n having two symphysial pores.  It differs from carolinae i n prickling and  possession of a reddened dorsal i n the spawning male, i n having a complete lateral line.  C.rhotheus i s probably also similar to the unpublished  new species of Robins, C.girardi„having the same characters i n common that carolinae has, except the number of symphysial pores.  C.rhotheus i s  geographically quite isolated from carolinae and girardi, both being eastern forms.  C.rhotheus seems to have more characters similar to carolinae  than to r i c e i , hence should be considered most closely related to i t . It i s interesting to note that the characters i n r i c e i that are similar to rhotheus are net usually those i n carolinae that are similar to rhotheus; each i s -more similar to rhotheus than to one another. As mentioned before, the spoonhead muddler seems distantly related to C.rhotheus.  The spoonhead sculpin also seems related to two forms i n  the U.S.S.R. described by Berg (1949), C.sibiricus and C.spinulosus.  The  flat heads, shallow bodies, small darkbands on the dorsal fins i n Berg's illustrations appear very similar to r i c e i .  A dorsal viewoof the head of  67 sibiricus shows the same wide head and hornlike upper preopercular spine as i n C.ricei. as noted by Wynne-Edwards (1952).  The following table  gives meristic counts of the three species. TABLE 20 MERISTIC COMPARISON OF COTTUS RICEI, SIBIRICUS AND SRENULOSUS SPECIES  DORSAL DORSAL ANAL SPINES RAYS RAYS  PECTORAL RAYS  ricei  7-10  16-19  11-16  14-16  sibiricus  7-8  17-19  12-14  15-16  spinulosus  7-8  16-18  12-14  14  LATERAL PORES 35-37  32-35  The pectoral ray counts of sibiricus are taken from illustrations, and hence may not be accurate.  It w i l l be seen that none of the meristic  ranges has sufficient distinctiveaess to provide separation, except l a t eral line pores.  This demonstrates their close relationship. It is  interesting to note that C.ricei keys down to C.sibiricus i n Berg's key (translated by Marie Jerkela of the Institute of Oceanography).  C.sibir-  icus and spinulosus are differentiated by the following section of the key: 13(14) Tail stem more than 11$ of the entire body length. Minimum body height not more than 40$ of the length of t a i l stem. Pelvic fins generally re%ch anus .... C.sibiricus Kessler. 14(13) Tail stem less than 11% of the entire body length. Minimum body height more than 50$ of the length of t a i l stem. Pelvic fins do not or scarcely reach anus .... C.spinulosus Kessler. It would seem that r i c e i i s a close relative of sibiricus.  The wide  separation (neither species in Alaska and sibiricus only as far west as the Kolyma River i n western Siberia) raises the question of how, i f related, they arrived at their present distribution.  68 INTERSPECIFIC DIFFERENCES Interspecific differences w i l l be dealt with by discussing d i f f e r entiating characters and evaluating! their taxonomic worth. Relative Gro wth Body proportions have been utilized l i t t l e i n this paper because insufficient time was available to develop this aspect.  Relative growth  characteristics have the disadvantage that they are modified by condition, size and developmental conditions.  They are not constant as  merisjtics are; as the organism enters different stages ©r "stanzas" proportions may alter.  Nevertheless proportions of various body parts  to one another are often useful i n separating forms such as hubbsi and rhotheus.  A sufficient series of representative measurements must be  utilized, unlike has been done i n the past where single specimens have sufficed.  Ths position of the ventrals relative to the anus, often  used i n the past, does not seem to be a valuable character i n B.C. species. The proportion of depth into length does not seem a valuable one as i t i s modified by fullness of stomach, starvation and reproductive.condition. The length of the head and the depth of the caudal peduncle were found to be useful. Color Generally color is not held to be a good taxonomic character since i t often fades on preservation.  However, some colors do survive alcohol  and formalin, and color i s useful i n the f i e l d .  As color differences  are often associated with behavioral difference (which are considered  69 constant characters) they may be quite useful; use should be avoided, of course, of those colors modifying with the background.  Color differences  i n Cottus surviving preservation and useful i n species separation were, number of saddles under the second dorsal, patterns of black marks on the spinous dorsal, presence of wide-bands or flecks on pectoral f i n , and mottling on the chin.  Sexual differences i n coloration of edge of spinous  dorsal and black infusion of the male were found to be less well preserved. Morphology The presence, absence or form of several characters designatable as morphological are useful i n differentiation.  The absence or presence of  teeth on' the palatine bones proved useful in- separating British Columbia forms. Robins (1954) found palatine teeth to be-pre sent i n some populations of cognatus and absent i n others.  Whether the palatine tooth patch  was i n contact with the vomerine teeth was found to be a good character. The number of pyloric cacae i n the species examined was not found to be diagnostic.  The tubularity of the nostrils was variable.  Some species  with a non-tubular nostril occasionally had semi-tubular nostrils.  Some-  times species like C.ricei with a non-tubular nostril possess tubular ones.  The character i s usually valid i n separating those with non-  tubular and tubular nostrils, however. Preopercular spines are a highly modifiable character i n the genus Cottus and within some of i t s species.  In asper and the shorthead sculpin,  variation of one spine occurred, i n cognatus and r i c e i , two spines.  This  character may be useful i f the extent of i t s variation i s appreciated. Robins (1954) found i t to vary with habitat.  70 The extent of prickling was found to be too variable to be useful. Frequently specimens of a species would be prickled a l l over or only i n a small patch behind the pectoral f i n or not at a l l .  Prickling, when  extending over the whole body, can be useful as a confirming character, but i f reduced, l i t t l e can be deduced from i t . The shape of the prickles themselves can be used i n sculpin taxonomy. This newccharacter is not applicable to f i e l d identification, since i t i s not visible i n uncleared fish.  It can, however, be applied in deter-  mining the relationships of fish.  The following illustration shows the  shapes of prickles i n species examined.  The shape and proportions of  the shaft - the vertical portion and the base - the round or oval portion at the base of the spine should be noted.  asper  rhotheus gulosus  cognatus  hubbsi  bairdi bairdi  base Figure 3«  Shapes and proportions of cottine prickles drawn from cleared specimens.  71 Variability does occur i n the shape of the prickles within a species. The typical shape is found i n the centre of the prickle patchj i t may vary at the perimeter. ual species.  The shape of prickle i s described under individ-  The odd vanes beside the spine i n gulosus are peculiar,  making the spine appear feather-like. It was found that some species possessed two pores on the t i p of the chin (see illustrations of ventral surface of head of different species), while others possessed only one. previously.  Robins (1954) noted this character  Dr.- R.M.Bailey (pers.comm.) states that i n some species the  fusion or lack of fusion of pores i s subject to marked variation.  The  following table shows that the amount of variation i n this character i n B.C. species i s small and that i t i s a good identification feature.  The  specimens were a random sample (those individuals used for clearing). A second sample from the collection is present for Cottus cognatus. A few non-British Columbia species are also included. TABLE 21 NUMBER OF CHIN OR SYMPHTSIAL PORES SPECIES asper aleuticus princeps bairdi shasta gpbio ricei bairdi punctulatus bairdi semiscaber shorthead sculpin hubbsi cognatus rhotheus  ONE PORE 400 135 6 10 4 21 1 0 0 0 1 0  TWO PORES 5 2 0 0 0 0 7 3: 9 35 462 33  72 Another previously unreported character found i n this study was the number of spines on the f i r s t pterygiophore of the spinous dorsal. In some species there were characteristically, two spines on the f i r s t basal of the dorsal, i n other species only one.  Table 23, on the following page  presents the variability found i n this character i n different species. Determination wasmmade on cleared specimens from British Golumbia. The exact function of differences i n the number rof spines on the f i r s t dorsal basal i s unknown. It appears unrelated to habitat.  Species bearing  higher spinous dorsal counts(C.asp_er and aleuticus) usually possess two spines, while those having low spinous dorsal counts have only one spine on the basal.  It i s possible that the possession of two spines strength-  ens the leading edge of the f i n .  The chief function of the f i n would seem  to be behavioral, however, not locomotory. Even i n uncleared fish the number of spines on-the f i r s t basal can be determined with f a i r accuracy.  When two are- present the bases of the spines  are in contact and form a V"j when only one i s present the bases of the M  f i r s t and next spine are separated by the width of at least one spine. In some species, such as cognatus and r i c e i , a high degree of variation in the number of spines on the f i r s t basal occured, amounting to 10% i n cogndus.  In such species the character may not be used for identification,  although i t may be used for indicating relationships.  In other species i t  might be used for an accessory character i n keys. Is i t i s not the simplest character to describe or determine perhaps i t should only be used in determining the relationships of species.  73  TABLE 23 NUMBER OF INDIVIDUALS IN VARIOUS SPECIES HAVING ONE OR TWO SPINES ON FIRST DORSAL BASAL SPECIES  ONE SPINE  TWO SPINES  3 0 6 46 :;5 22 39. 12 7 4 . 5  82 48 0 5 0 2 1 2 0 1 0  asper aleuticus princeps cognatus shorthead sculpin rhotheus hubbsi ricei carolinae bairdi bairdi hypselurus  When the number of spines on the f i r s t basal i s away from the norm the number of spines i s usually abnormally high or too low. Hence two spines on the basal where there are usually one may result from crowding.  One spine where there are usually two may result when there are  fewer than the usual total number of spines. Meristic Characters Meristic characters have been often used i n the past for differentiation of forms.  Increasingly i t has been shown that their high var-  i a b i l i t y i n many cases excludes their use for specific differentiation. The preceding studies on intraspecific variation have shown that meristic characters may change with several factors such as latitude, altitude and temperature.  It is only when the f u l l effect of these on  variation i s known that serial characters should be used i n identification and naming. Most of the meristic characters i n Figure 7 show significant  74 differences i n means. Although this establishes that the species i n volved are different, i t doesn't- necessarily enable one to differentiate them. However, reference to the graph w i l l show that some characters do not overlap.  That meristic characters i n some cases are useful i n sep-  aration of species should not be obscured.  Also the overlap that occurs  i n the extremities of the ranges may occur so infrequently that the character may be used for separation with a f a i r degree of certainty. The u t i l i t y of characters shown on Figure 7 can be obtained directly so that no discussion of these characters w i l l be given. Branchiostegals The usual number of branchiostegals i n Cottus i s six. Occasionally seven are found.  The frequencies with which sevens occur i n different  species varies but not sufficiently to be diagnostic. Basals The number of basals i n the anal f i n equals the number of rays, but the number of basals under the dorsal f i n may differ from the number of spines and rays.  Between some species the ranges, and between others,  the modes, serve as a means of distinguishing.  The table following sum-  marizes the number of basasl under both dorsal fins.  75 TABLE 24 NUMBER OF BASALS BELOW THE DORSAL FINS SPECIES 23 asper aleuticus pririceps cognatus shorthead sculpin rhotheus hubbsi ricei carolinae c. bairdi b.  1  NUMBER OF BASALS 24 25 26 27 28  29  30  31  2 20 43 8 21 9 1 2 3 6 21 22 1 1 1 1 21 17 7 4 26 10 1 6 2 2 1 1 3 2  17  1  Caudal rays The number of giajjor caudal rays (attached to the two hypural plates) i s so constant i n the genus that, like the number of branchiostegals, i t i s of no specific taxonomic importance.  The minor rays  (not attached to hypural plates, above and below the major rays) vary greatly, i n fact more than any^other count. i s so great that they aire unuseable.  In most cases the variation  The fact--that -they cannot be  readily counted without clearing decreases any value that they might have.  Table 25 below gives the frequencies of minor caudal counts for  several species. It w i l l be noted that the dorsal minor caudal counts are usually higher than the ventral.  76  TABLE 25 , VARIATION IN MINOR CAUDAL RAYS DORSAL MINOR CAUDALS  SPECIES  6 asper aleuticus bairdi shasta cognatus shorthead sculpin hubbsi rhotheus ricei carolinae c. hypselurus bairdi b.  7 8 9 10 11  1 4 32 10 1 5 8 4 3 2 5 13 14 9 2 1 2 2 3 8 5 1 4 8 4 1 1 5 1 1 3 3 2 4  VENTRAL MINOR CAUDALS 4  5 6 7 8 9 1 2 5 3 5  1 3 I." 2 J  2 3 19 3 8 6 1 1 1 6 16 11 3 2 7 6 1 11 1 2 1 1 3 2 1  19 1  10 8  11 12 13 14 1  1  2  2  Lateral line Lateral line pores are a highly useful character. be seen under the description of each species.  Their numbers may  The length of the lateral  line i s quite closely proportional to the number of pores.  The position  of the end of the lateral line relative to the dorsal fins or caudal peduncle may, therefore, substitute, and as i t i s more easily determined i s a better character.  One disadvantage of the lateral line as a taxonomic character  i s that i t i s not usually complete u n t i l a size of about 60mm. (total length) has been attained.  As mentioned i n the descriptions, exceptions i n the  completeness of the lateral line, i.e., incomplete when normally complete, do occur. Reproduction Time of reproduction does not lend i t s e l f to identification of specimens i n hand, but i t does to the finding ofethe relationships of species.  '77 Two types of spawners would appear to exist i n British Columbia. 26 gives spawning time of B.C. sculpins.  Table  It i s known that Cottus asper,  aleuticus, hubbsi, and rhotheus spawn i n the spring.  The eggs i n these  species are large just before they spawn. Limited observations would indicate that they are not large i n the winter.  This, and the presence  of large (1.0-17) eggs i n Cottus cognatus from August to November (no specimens collected later), seems to indicate they are f a l l spawners. Whether cognatus spawns i n the f a l l or not, the earlier development of eggs (when none are present i n others) indicates a definite physiological difference from asper, aleuticus, hubbsi and rhotheus.  Specimens of  Cottus r i c e i from Lake Michigan collected on 11 June possessing eggs 0.8 mm. i n diameter might indicate summer or f a l l spawning. ferences are of taxonomic importance.  These d i f -  If changes i n spawning time exist,  deep-seated behavioral and physiological differences i n the adults and young hence might be expected. Ecology Modern systematics utilizes other than morphological characters. Physiological, ethological and ecological characters are also employed. Table 26 summarizes relative differences i n ecology of B.C. species of Cottus.  Insufficient data were available to draw conclusions from eco-  logy of the spoonhead and shorthead sculpin.  Their data are included  only for the sake of completeness. The data are subject to the limitations given i n the methods. Since the ecological data are of comparative value only, no description  78  was given under individual species.  To evaluate ecological differences  statistical tests were performed on the differences between the species. Tests cannot be performed on a l l the differences since there are too many combinations.  Only certain differences w i l l be pointed out.  It w i l l be noted i n Table Zd that Cottus asper and Cottus aleuticus have been recorded as occurring in brackish water i n 2% of the collections. Doubtless they occur f a i r l y frequently in brackish or even salt water. Snyder (1908a) stated that the two were able to tolerate salt water. C.L.Hubbs (1921a) records the prickly sculpin from two brackish lagoons in California.  Clark Hubbs (1947) recorded Casper as venturing downstream  into chlorinities of .57 i n Salinas Paver, California.  Gilbert (1895)  found C.aleuticus i n brackish water i n Alaska and was able to keep one for several days i n a saltwater aquarium.  The only other instance of a  British Columbia species of Cottus being i n saline-water is given by Dunbar and Hidebrand .(1952).  They found the C.cognatus i n brackish water  i n Ungave Bay, northern Quebec. This, the only instance I know of i n this species may merely be another instance of freshwater fish entering  the sea  in. the northern parts of their distribution (such as Prosopium cylindraceum). It does not seem to be a normally salt water inhabiting species. *o test the significance of habitat difference between Cottus asper and aleuticus a chi square test was run on the distribution of numbers of collections taken i n lakes, streams and brackish water.  The difference  was found to be significant, p<0.02. The difference i s chiefly attributable to the more common occurrence of asper i n lakes.  Another test was run of  the "width of streams i n which asper and cognatus were collected. ference was found to be significant, p< 0.05.  This dif-  When differences between  79 the slimy and torrent sculpin were tested as to current, the difference was found attributable to chance (p=.3-»2).  The above tests indicate  that habitat differences exist i n B.C. species and that these may be s t a t i s t i c a l l y significant. •tyie prickly sculpin seems to be ecologically distinct from other B.C.  species by i t s more common occurrence i n lakes than streams, and  i t s more common occurrence on sandy bottoms.  The Aleutian sculpin i s  distinguished by i t s high degree of preference for narrow, swift, clear streams.  Frequent occurrence on gravel or mud bottoms, i n clear narrow  streams characterize the slimy sculpin.  The Columbia sculpin would seem  to usually inhabit swift or slow clear wide streams and frequently lakes. The torrent sculpin i s , as i t s name indicates, an inhabitant of strong currents.  It has been recorded i n three lakes; but two of these, the  Upper and Lower Arrow Lakes, possess a definite current.  T  he third  collection was made within the influence of an entering stream.  A l l col-  lections have therefore been made i n some current. Differences i n food also occur. i n food of asper and rhotheus.  Northcote (1954) discusses differences  The larger size of mouth i n rhotheus per-  mits i t to u t i l i z e larger food items at an earlier age than asper.  Present  information would indicate that cognatus i s not piscivorous, while asper and rhotheus are.  Palatine teeth are present i n asper and rhotheus and ab-  sent i n cognatus.  Possibly these food preferences and morphological char-  acters, fish diet and palatine teeth, are correlated.  TABLE 2& COMPARATIVE ECOLOGY OF B.C. SCULPINS - Figures i n parenthesas and percentages refer to the number of collections. SPECIES  HABITAT  DEPTH  •Cottus aleuticus  Streams 68$ Lakes 30$ Brackish 2$ • (41)  Streams 1 f t . or less usually, up to 4 f t . (10)  Cottus asper  Lakes • 55$ Streams usually 1-5 f t . ; lakes Streams 43$ 1-10 f t . Brackish 2$ (140) (23)  STREAM WIDTH  TEMPERATURE  CURRENT  WATER COLOR  11-20 f t . 50$ 6-20 f t . 25$ + 50 f t . 25$ (12)  Swift 75$ Mod. 13$ Slow 12$ (8)  Clear 72$ Glacial 14$ Cloudy 14$ (7)  Cold  Game fish and Dolly Varden  + 50 f t . 31$ 21-50 f t . 25$ 11-20 f t . 25$ 6-10 f t . 13$ I- 5 f t . (16)  Swift 50$ Slow 43$ Mod. 7$ (14)  Clear 47$ Cloudy 43$ Muddy 13$ Glacial 7$ (15)  Warm  American Merganser, lake and Dolly Varden char, cutthroat;and\ .1 brown trout, squawfish, ling and sculpins.  Streams 69$ Streams 1-3 f t . Lakes . 31$ up to 5 f t . ; lakes 5-6 f t . . (54) (23)  II- 20 f t . 55$ 6-10 f t . 18$ 21-50 f t . 18$ + 50 f t . 9$ (22)  Swift 45$ Slow 27$ Mod. 18$ S t i l l 9$ (22)  Cottus n. sp.  Streams 100$ (3)  + 5 0 f t . 50$ I- 5 f t . 50$ (2)  Swift 100$ (2)  Cottus hubbsi  Streams 60$ Lakes 40$ (10)  Streams 1-3 f t . , usual., range g-5 ft. (5)  21-50 f t . 50$ Swift 43$ + 50 f t . 25$ Slow 43$ II- 20 f t . 25$ Mod. 14$ (7) (4)  Clear 80$ Glacial 20$ (5)  Cool  Cottus r rhotheus  Streams 84$  Streams 1-3 f t . , rarely 1-5 f t . (6)  + 50 f t . 50$ Swift 38$ 21-50 f t . 38$ Mod. 38$ 11-20 f t . 12$ Slow 24$ (16) (8)  Clear 50$ Glacial 33$ Cloudy 17$  Cool  Cottus  Streams 100? (2)  Streams 1-3 f t . (1)  + 50 f t . 100$ Mod. 100$ Muddy 100$ (2) (1) (1)  Cottus cognatus  PREDATORS  CO  Clear 58$ Cloudy 26$ Muddy 16$  Cool  (19) Cool  Lake char, pike and o ling.  TABLE 26 continued SPECIES  REPRODUCTION  . .BOTTOM  Cottus aleuticus  Boulder 36$ Gravel 36$ Rocks 18$ Sand 10$ (11)  Spawn from Feb. to mid-June in creeks under boulders. Eggs orange, 1.5-2.0 run.  Cottus asper  Sand 35$ Detritus 9$ Gravel 26$ S i l t 4$ Mud 13$ Boulder 4$ Rock 9$ (54)  Spawn from mid-Feb. to June i n streams under boulders. Yellow or orange eggs. Downstream spawning migrations i n coastal streams  Cottus cognatus  Gravel Mud Rocks Sand (48)  Cottus n. sp. .  Rocks 66$ Boulder 34$ (3)  Cottus hubbsi  Gravel 40$ Boulder 20$ Rocks 17$ Sand 10$ (10) Mud 10$  Probably spawn from April to June.  Cottus rhotheus'  Gravel 45$ Rocks Boulders 19$ Sand  Probably spawn from April to June  Cottus ricei  ' Mud  32$ Boulders 6$ Ovaries are ripe from August 25$ Clay 6$ to at least November. Eggs 1.5 to about 2 mm. 17$ Silt 2$ 10$ Detritus 2$  100$ (l)  12$ 12$  F 0 0 D  Fry - plankton and aquatic insect larvae; Adults - insect larvae, fish, C r u s t a c e a , molluscs,  Aquatic insect larvae  Fry - plankton, midge larvae; Adults - insect larvae and fish.  Ripe Individual on 11 June from Lake Michigan.  Part of habitat data from Carl and Clemens (1953). "Food data i n part from Northcote (1954) and Munro and Clemens (1937)  82 KEY TO THE FRESHWATER SCULPINS OF BRITISH COLUMBIA In order to summarize the differences between species of British Columbia, a key containing most of these differences i s provided below. 1  (12) Upper preopercular spine not long and shaped like buffalo horn and head not greatly flattened as i n Figure 4«  Figure 4 2 (5)  One pore on midline of t i p of chin (see Figure 5);  caudal  vertebrae 24-28; 2 spines on the f i r s t dorsal basal; dorsal spines usually 8-10; 26-31 basals under the dorsal fins; commonly enter brackish water; lateral line always past second dorsal i n specimens over 60 mm. total length. /  Figure 5 3 (4)  -  Figure 6  Posterior nostrils not tubular (Figure 6); anal rays 15-19; palatine teeth present; black spot present on the posterior portion of the f i r s t dorsal and then orange border along dorsoposterior edge; 2-3 spines on preopercle (skin must be removed); prickles usually present on back and sides, occasionally reduced to patch i n a x i l ; pectoral rays 15 to 18. prickly sculpin - Cottus asper  83 Posterior nostrils tubular (Figure 6); anal rays usually 12-14 (rarely 15); no palatine teeth; no black spot present on the posterior portion of the f i r s t dorsal fin; wide orange band present on f i r s t dorsal of only spawning male; one spine at corner of preopercle; prickles i n a x i l only or absent, skin slippery; pectoral rays usually 13-15 (occasionally 16) Aleutian sculpin -  Cottus aleuticus  One pore on either side of midline of t i p of chin (see Figure 4)j 20-24 caudal vertebrae; usually one spine on f i r s t dorsal basal; dorsal spines usually 7-9; dorsal basals usually 23-26 (occasiona l l y to 28); never enter brackish water i n B.C.; lateral line complete or incomplete. Usually strong prickles on back and sides; two sharp dark saddles under second dorsal; strong mottling on chin; lateral line complete i n specimens whose total length i s over 60 mm.; pectorals with speckles rather than wide crossbars on rays; 24 or 25 (rarely 26) basals under the dorsal fins; usually 15 to 16 dorsal rays (rarely 17); caudal peduncle enters head 2.65-3.0 (as opposed to 2.19-4.5); head large 2.9-3.2 into standard length (as opposed to 3.0-3.9); palatine teeth i n contact with the vomerine patch of teeth; dark median band absent i n f i r s t dorsal. torrent sculpin -  Cottus rhotheus  Prickles reduced to a weak patch behind pectoral f i n (rarely extending onto sides and back past area covered by pectoral f i n ; usually three, sometimes two, mottled crossbars across back under  84 second dorsalj chin evenly speckled; lateral line not complete except sometimes i n hubbsi; pectorals with.bars on rays forming bands; basals under dorsal fins usually 25-27 (rarely 24-28); usually 16-18 dorsal rays (rarely 15-19); head entered 2.9-4.5 times by depth of caudal peduncle; head small, entering standard length 3*0-3.9 times (2.9 occasionally); palatine teeth, i f present, not i n contact with the vomer; dark marks i n f i r s t dorsal often forming median band. 8  (11)  Palatine teeth present; anal rays 12-14 (rarely 11); ventrals with 4 rays.  9  (10)  Three preopercular spines; lateral line extends past second dorsal; 7-8 dorsal spines; head 2.9-3.2 times into standard length; caudal peduncle 3.7-4.6 times into head; usually 14-15 pectoral rays (13-16). Columbia sculpin  10 (9)  -  Cottus hubbsi  One to two preopercular spines; lateral line does not extend past second dorsal; 8-9 spines i n f i r s t dorsal f i n ; head 3*2-3.8 times into standard length; caudal peduncle 3«2-3.6 times into head; usually 13-14 pectoral rays. Shorthead sculpin  11 (8)  -  Cottus n.sp_.  Palatine teeth absent; anal rays 9-12 (occasionally 13); ventrals with 3-4 rays; lateral line not extending past second dorsal f i n . slimy sculpin  -  Cottus cognatus  85 12  (1)  Upper preopercular spine long and resembling buffalo horn; head greatly flattened; lateral line complete; caudal vertebrae 23-25; one pore on midline of t i p of chin. spoonhead sculpin  -  Cottus ricei  86  .Co  i i i ! 1:1 L1--. If:: i:l;i':'r. "if:! i ". ii:: 1;!' : liii i;i-l i : i Till ill 1 n i l rlu  ill  n;  i n - ill:  ;4  dip irti :us as jei  ~4  :  _  1  S3  is  -zrz li  ;;.n:  =Ei is}  li  i3ir r  S i  iiiti Cllf  if-' 1*  -ri fei  i l l i m i ii"-.  :  M  9  IE  :•:  ; :  ;  —  10  ;!:,;•'  ii.\  .1  |  I  #! i;  Oi T^-  ISAL IA  i  -_' -  » : i ^ S ± ~ 1 -1H 17." - i i 1'' frf- 1 -.i" •nt:~ i=ii l i ' i l U i liL-: 1  1  IS  /9  !  ir  20  -  '1 •  :  1  ii"  fFr  —  i l  .... ir-'i l i l l  rr.:  ANi\L  5?  ; -•  it  22 I  ;  •:-  H? H u ) b s  v -  rj;  "I  llii ::! U'l ;. '  "ii2i  r — i -r.B  Hi-  ri? CO SQ. 1:;-  :  i •.  . ! s  S5-  CIS per  1  r . t;.;  It  .  ir-i r: -  H'r  iii ;:  TTiT i't.  !;! 1 ; '1  ::i  :-;-.  = r l H E ilr'r  to-l i s :  ;  •.-H-l 7 : 1:1;  Or  :  iii:*  ;  r  — ' t — — :frr  i i r i::l -l:i ;:: i i' i  i-lf i : : i ; i - i 1^1 I i i •'::• 1311 5 1  :  'ill  :  Irxl  ;  i;  "1 il.  Ti-i  i;5  *ill rif ei llli .1- s j p n " . i . " rlii" i i i l l r :1 jiin tiif i li i f i s V i i ; Vif . - . ^ 1: H Hit =~ i t h e'ui ill: v ; i 'i r. ""-•'I HI; liit llr r * -iiii :tl 1-W - - .•I": r ' L -=S| 7 lib' w> a t i 8 H »o»  :!-:  1-11  rh i ' t f i BUS ---' r ii.- I: 1 il-'i »2i ; - l . " i " /3 irii :• 7-il'i 11: i lirl 1-' "ni Hit iz—:•H--Vi ifl' i : i :lf| It;; Sir . . : : ; r.r. - ! ; • I.:ri 5 ei =rfi Ill: . . . . i':;i i.n; Hi? m - 1-1 •l •Hi l i l -iiii agi ( f l t IS .in,'. 351 l i i i T.-:T i i i : HI" u h f _il •511 i H l :=I " ; : :H|I N o t hei 18;; T .' ! 1 -r rr. r /3  IS  14.  S  r  — /7  16  IS  lv\  ^l  • - r i cei  :  ITli .rill S I ; •-!- l - r 1*1; l i S •rnT irrl -.rt; 115 jxhi isi-  ITS iii; "< 69 Q t i s ; i  •li-i. nil:  ;  1":  I-::.  rlVAthe jg [  - : " ' * l : : h 20  h i ; i-irr r  1 '' 117  IS  m sLi y Kil  ——  181 -j i  1 : -1 i - 1 -|!;. • •i l l :!•. • .:l • . T : •••I EE RAE  !  ,  1: :  ••-.-y •  :  :  —  \  "M  l i l l : ; ; ; 22  5  '<••  V£l \  1  fih 2/ ^ i  /6  :!'  ::-::  llil.  ;:i-  Rt  IT Of  • 1. _j 14  -~.  ; 1:1  •iiH u b t « r  {Hi : : i !  -.-•:  m  :i::  /  :r  liir i-li •:1 - r • ^i  ° u t Cllf i a ipe  j...  :  'i  frip -I  25  24;  23 "I •  :  »-  ' •1  Figure 7  c 0+7 :|;'' '  U  •  s  1  I-  RI  :  ••• i i  .  i .::!'! •.|:. . I 28 ,27' i' ; standard mean -7 f- i-^|.er-i;ortiop j  , I-  ' -  26  ' I. •  |  ...j—m  ige,  87  Figure 8.  Distribution of B.C. species of Cottus  88 SUPRASPEGIFIC RELATIONS IN COTTUS The classification of species within the genus Cottus has varied. In 1842 DeKay placed those cottines bearing 3 ventral rays i n the genus Uranidea.  This character has been shown to very within the species level;  his generic distinction has therefore been recognized as invalid.  Several  other now invalid genera for cottins were erected since this date which w i l l not be discussed (see synonyms of Cottus).  Jordan and Evermann (1898)  divided Cottus into three subgenera, Pegedictis (short preopercular spine at corner and palatine teeth), Cottus (same but lacking palatine teeth) and and Tauridea (preopercular spine very large, as large as eye and spirally hooked).  The f i r s t two of these subgenera are not now considered as valid  since palatine teeth may very within species- and probably occur i n unrelated groups.  The last was retained by Robins (1954) as a species group.  Jordan,  Evermann and Clark (1930) retained and confused several old and invalid subgenera. Robins (1954) thoroughly revised the systematics of eastern cottins (excepting Cottus cognatus).  He divided them into three groups:  the  banded sculpin, the redfins sculpins and a group containing Cottus r i c e i . Some western species studied i n this thesis did not f i t Robins' key to species groups.  Examination of some western and some eastern sculpins  and Robins' thesis suggests that there are three major species groups, one of which subdivides i n two.  Group I includes Pacific forms, group II  holarctic species, the eastern American forms of which break into Ila (sexually dimorphic) and l i b (non sexually dimorphic species), and lastly  89 group III i n which are placed r i c e i and perhaps related palearctic forms. It i s likely that examination of Soviet species w i l l require the addition of another group to these three, i f not modifications to the grouping. As the required information was not available on a l l North American species, and as insufficient specimens were available, modifications of species groups may well be required on addition of this information.  The exist-  ence of three species groups w i l l be established i n the following discussions. CHARACTERISTICS OF SPECIES GROUPS Caudal Vertebrae The number of caudal vertebrae i s the principal character on which the three species groups are based.  Caudal vertebrae were f i r s t used taxon-  omically by Schultz (1930) who used them to separate western Washington species of Cottus.  He divided them into two groups, those with 21-24 and  those with 25-29 caudal vertebrae.  In 1936 Schultz produced a key to the  fish of Washington and Oregon. Palatine teeth were the main character used in this key, caudal vertebrae were used i n separating small species groups. Schultz and. Spoor (1933) also used caudal vertebrae.  Hubbs and Schultz  (1932) present a table showing two groups of Cottus, one having 20-23 and the other 24-28 caudal vertebrae.  Despite the obvious dimorphism, no  comment was made on the existence of two species groups.  Robins (1954)  made no mention of caudal vertebrae in his thesis on eastern sculpins. Table 27 presents a l l data obtainable on ranges of caudal vertebrae. In order to make comparisons of species, worldwide counts were obtained from several sources.  The total number of vertebrae i n Soviet species was  translated from. Berg (1949).  To convert his total counts to caudal verte-  90 brae counts, 12 was subtracted.  Twelve abdominal vertebrae was the  greatest number of vertebrae usually found i n seven species of Cottus examined (counts ranged from 9 to 13).  Counts were also obtained from  Schultz (1936) and Hubbs and Schultz (1932). Table 27 indicates the existence of three groups - 24-29, 20-24, and 23-25 caudal vertebrae.  It might be argued that the number of vertebrae  does not separate the species into two groups, that overlap occurs at 24 vertebrae and that one species straddles the 24 count.  However, ricei i s  the only species straddling the 24 count out of twenty-five species. If the distribution of vertebral counts was chance one would expect more cases of overlap across the separating l i n e .  The amount of overlap occur-  ring i n other species than r i c e i (both other groups extend to 24) i s small, 24 being an unusual count i n these species.  Other evidence for the exist-  ance of three groups w i l l be dealt with under the headings of the characters that separate them. Dorsal .Spines Table 28 gives the ranges of the dorsal spines i n groups I and II. Unfortunately means and statistical measures of deviation are not available for most of the species dealt with,  " t " tests therefore cannot be used to  test the significance of difference between numbers of spines i n groups I and II. In most species, as may be seen from the graphs i n Figure 7, the midpoint of the range would be a f a i r indication of the mean. A chi square test on the differences i n distribution of midpoints above and below 8.75 i n the two groups yield a chi square value having a probability of less than .01.  91 TABLE 2-7 RANGE OF CAUDAL VERTEBRAE SPECIES 20  NUMBER OF CAUDAL VERTEBRAE 21 22 23 24 25 26 27  28  29  —  ~  Group I asper aleuticus princeps amblvstomopsis czerski  —  kesserli pretusus Group I I rhotheus gulosus hubbsi gobio  —  kneri poeciolopus tubulatus  •  beldingi n.sp. bairdi bairdi hypselurus carolinae _c.  _  cognatus klamathensis bendirei Group I I I ricei  :  92 Differences i n the number of dorsal spines might possibly be attributable to a correlation between the number of dorsal spines and dorsal rays.  If this were the case the dorsal spine differences would  not be increasing the differentiation between groups I and II.  To find  i f the higher number of spines was related to having more vertebrae, chi square tests were applied to each group.  Chi square tests showed that  there; was not significant association between the number of caudal vertebrae and the number of dorsal spines within each group.  The significantly  higher tendancy i n group I to have more dorsal spines i s then dissociated from their having a higher vertebral count.  The higher number of dorsal  spines i n group I then confirms the existence of two groups.  Table 28  gives dorsal spine counts i n the two groups. TABLE 28 DORSAL SPINE RANGE IN GROUPS I AND I I SPECIES  ~ 5  6  NUMBER OF DORSAL SPINES 7 8 9  Group I asper aleuticus princeps amblystomopsis czerski kesserli protusus  10  11  1  Group II rhotheus gulosus hubbsi go bio kneri poecilopus tubulatus beldingi bai rdi bairdi  —  : t  " — —  n.sD.  'hypselurus carolinae c. cognatus klamathensis bendirei  —  —  :  •  93 Dorsal Rays Table 29 gives the ranges of dorsal rays i n group I and group II. It may be seen that the ranges are usually higher i n group I than group II. A chi square test shows that the difference i s significant (p <.0l). Chi square tests also show that no relationship exists between the number of rays and vertebrae i n group I (p=0.5-0.3) or group II (p=0.1-.05). The number of dorsal rays then aids in the definition of groups, although the high overlap makes separation d i f f i c u l t on this basis.  It must be  remembered than i n many species, particularly where the range i s small, large series of specimens have not been examined.  Therefore, one expects  that, i n the future, ranges may be extended, which may increase the degree of overlap. TABLE 29 RANGES OF DORSAL RAYS IN GROUP I AND I I SPECIES 14  NUMBER OF DORSAL RAYS 16 17 I S 19 20 21  15  Group I asper aleuticus princeps amblystomopsis czerski kesserli protusus Group II rhotheus gulosus hubbsi £obio kneri poeeilopus tubulatus beldingi bairdi b. n.sp. hypselurus carolinae c. cognatus klamathensis bendirei  • • '  •  :  •  ~ :  ' —  •  —  22 :  —  23  94 Anal Rays Table 30 gives the ranges of the number of anal rays i n groups I and II.  Group II was found to have significantly more of the midpoints of i t s  ranges above those of group II (p= -.01). TABLE 30 RANGES OF ANAL RAYS IN SPECIES GROUP I AND I I SPECIES 9  10  11  Group I asper aleuticus princeps ambly sto mopsi s czerski kesserli protusus Group II rhotheus gulosus hubbsi gobio kneri poecilopus tubulatus beldingi n.sp bairdi b. hvpselurus cognatus klamathensis bendirei  NUMBER OF ANAL RAYS 13 14 15 16 17  12  18  19  20  :  .  :  ' •  .  —  Ventral Rays There seems to be a higher frequency of forms having 3 ventral rays in group II than i n group I.  Only one of six group I species ever had 3  ventral rays, while 6 out of 13 of group II species at least sometimes had 3 ventral rays.  95 Pectoral Rays A chi square test on the midpoints of the ranges of the pectoral f i n rays of the two groups showed they vrere not statistically different i n this respect. Lateral Line Only one out of seven species i n group I normally had an incomplete lateral line, while 7 out of 11 of group II normally had an incomplete lateral line.  A greater tendency i n group I I exists to have incomplete  lateral lines. Symphysial pores A l l three of the species examined i n group I (asper. aleuticus and princeps) normally possess one pore on the t i p of the chin.  According to  Robins and according to my own data, seven out of eight species I I possess two pores on the t i p of the chin, Cottus gobio, the Eurasian species, possessing only one.  Cottus girardi (manuscript name of Robins') has but  one pore and probably belongs to group II. Possibly i n the last two species the one pore has been secondarily derived by fusion.  Cottus r i c e i , the  only known member of group III, has but one pore. Other Characters Other characters such as palatine teeth, tubularity of the posterior nostril, prickling and preopercular armature seem to occur sporadically i n both groups.  Their ready gain or loss i s presumably the result of converg-  ent and divergent evolution.  96 Distribution A l l species of group I are found i n Pacific drainages except kesserli which i s found i n Lake Baikal, U.S.S.R. of Nearctic and Palearctic. Species of group II are holarctic i n distribution.  The homogeneity of dis-  tribution of group I would confirm the common origin of i t s members.  There  are indications that group I i s more tolerant of saline water than i s group II. Cottus asper and aleuticus of group I are known to enter salt water and the presence of several others of this group i n maritime islands would also suggest this.  Of group II, cognatus (Dunbar and Hildebrand 1952)  and poecilopus (Splastenenko 1955) have evidenced a b i l i t y to enter slightly saline waters.  Most of the latter group are found away from the coast,  however. SPECIES GROUPS The morphological differences and distribution of the high and low vertebrae groups (I and II) would suggest them to be natural taxons. The characters of r i c e i would, at present, differentiate i t from I and II (see key). Further information on i t s anatomy and that of other freshwater cottids may indicate i t s derivation which i s not clear'.  Robins' groupings  have not been deeply examined; they have been adopted as subgroups of II to which they belong without c r i t i c a l examination since specimens of most eastern species were not available for study. The relationships of the different species groups are indicated i n the following key.  The species i n each group are listed following each  group, the probable members are i n parentheses.  97 KEY TO SPECIES GROUPS IN COTTUS  1  (4) Upper preopercular spine not longer than eye and not buffalo-hornlike; head not greatly flattened; caudal vertebrae 20-24 or 24-28, not 23-25; lateral Line complete or incomplete; one or two pores at symphysis.  2  (3) Caudal vertebrae 24-29; one chin pore; 4 ventral rays; lateral line usually complete; dorsal spines usually 8-10 (rarely 6-11); anal rays usually 14-18 (rarely 12-19); dorsal rays usually 18-23  (rarely  16-23); found, with one exception, on Pacific slope of North America and Asia. Group I  -  Cottus asper, protusus, aleuticus, princeps, amblystomop-  sis, czerski, kesserli, 3  (asperimus)  (2) Caudal vertebrae 20-24; usually 2 symphysial pores; 3-4 ventral rays; lateral line incomplete or complete; dorsal spines usually 6-9 (rarely 5-10)> anal rays 11-15 (rarely 10-16); dorsal rays 15-19 (rarely 14-20); holarctic. Group II - Cottus rhotheus, gulosus, hubbsi, gobio, kneri, peecilopus, tubulatus, beldingi, bairdi, hypselurus, carolinae, cognatus, klamathensis, bendirei, n.s£., baileyj girardi. a (b) Sexual dimorphism i n breeding features; breeding male characterized by a general black suffusion on body, a mil  developed  and enlarged anal papilla which extends to the anal base as a flat triangular process, blackish fins, a broad red or orange border on the f i r s t dorsal fin, chin uniformly pigmented;  98 palatine teeth weakly developed (the palatine patch shorter than the width of the vomerine patch and separated from i t or absent). Group Ila Redfin sculpins, Cottus bairdi, hypselurus, baileyi, cognatus, (hubbsi). b (a) Sexual dimorphism i n  breeding  features lacking; males and  females similarly colored, anal papilla a small rounded protuberance i n both sexes.  Fins never black, the spotting  restricted to the surfaces o f the rays. cally mottled.  Chin characteristi-  Red border on f i r s t dorsal f i n reduced or  absent. Group l i b Cottus girardi,  Carolina^  (rhotheus).  (l) Upper preopercular spine longer than diameter of eye; buffalolike head greatly flattened; caudal vertebrae 23-25; lateral line complete; bones of head cavernous; one chin pore. on Pacific slope Group III - Cottus r i c e i (sibiricus, spinulosus).  Do not occur  99 CONCLUSIONS 1.  Differences were found i n extent and degree of prickling between lake, stream and brackish Cottus asper.  River asper possessed more anal  rays, fewer pectoral rays, more vertebrae and fewer branchiostegals than lake. 2.  Populations of Casper i n or near brackish water near the coast were found to be significantly different than those just inland, i n extent of prickling and number of dorsal rays, pectoral rays, and vertebrae.  3.  Populations, altitude, isotherms and latitude were shown to be related to meristic variation i n Casper.  4.  Significant correlations exist i n Casper between dorsal rays and vertebrae and between anal rays and vertebrae.  Pectoral rays and dorsal  spines showed no significant correlation with vertebrae. 5. Differences i n variability of dorsal spines, dorsal rays, anal and pectoral rays and vertebrae were shown to exist i n Casper. 6.  Body proportion and meristic differences were found i n river systems and at different latitudes i n Cottus cognatus.  7. No significant sex differences i n dorsal spines, dorsal rays, anal rays, pectoral rays and vertebrae were found i n Ccognatus. 8.  C.philonips was found to be synonomous with C.cognatus.  9.  No sex differences i n dorsal spines, dorsal rays, anal rays, pectoral rays and vertebrae were found i n Crhotheus.  10". Significant differences exist between B.C. and Washington i n pectoral rays of Chubbsi.  IGO 11. Significant differences exist i n pectoral rays of coastal and noncoastal C.aleuticus. 12. A latitudinal cline i n vertebrae, increasing northwards, occurs i n C.aleuticus. 13. Clines were shown to exist •• from southeast to northwestern North America i n anal and pectoral rays i n C.ricei. 14. Differences were shown to exist between B.C. species i n coloration, body proportion, meristics, distribution and ecology. 15. The taxonomic characters used to classify Cottus were evaluated. 16. Three natural groups were found i n cottines, based on caudal vertebrae and affirmed by other characters.  1  Figure 9  102  Cottus hubbsi Bailey and Dimick Figure 10  Figure 11  104  LITERATURE CITED Aim, G. 1952. Influence of heredity and environment on various forms of trout. Inst.Freshwater Res., (29):29-34Bailey, R.M. and Gosline, W.A. 1955. Variation and systematic s i g n i f i cance of vertebral counts i n the American fishes of the family Percidae. Misc.Pub.Mus.Zool., U.Mich. (93):l-44Bailey, R.M., Wynn, H.E. and Smith, C.L. 1954. 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Notes on Cottus asper and Cottus aleuticus. (90):7-8.  Copeia  Hubbs, C.L. 1921b. The latitudinal variation i n the number of vertical fin-rays i n Leptocottus armatus. Occ.Pap.Mus.Zool., U.Mich. (94):l-7« Hubbs, C.L. 1926. The structural consequences of modifications of the developmental rate i n fishes, considered i n reference to certain problems of evolution. Amer.Nat. 60:57-31. Hubbs, C.L. 1927. Notes on the blennioid fishes of western North America. Pap.Mich.Acad.Sci. Arts and Let. 7:351-394Hubbs, C.L.  1940. Speciation of fishes.  Amer.Nat.Hist. 74:198-211.  Hubbs, C.L. and Hubbs, C. 1953* An improved graphical analysis and comparison of a series of samples. System.Zool. 2:49-57Hubbs, C.L. and Lagler, K.F. 1949. Fishes of the Great Lakes region. Cranbrook Inst. Sci.Bull. (26):1-186. Hubbs, C.L. and Raney, E.C. 1951. Status, subspecies, and variations of Notropis cummingsae, a cyprinnid f i s h of the southeastern United States. Occ.Pap.Mus.Zool., U.Mich. (535). 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Distribution and taxonomy of fishes i n the Mackenzie drainage of British Columbia. J.Fish.Res.Bd. Canada. 13:759-789. Livingston, D. S. 1952. The freshwater fishes of Nova Scotia. Nova Scotian Inst.Sci. 23:1-90. McGregor, E.A. 1924. A possible separation of the river races of King Salmon i n ocean caught fish by means of anatomical characters. California Fish and Game 9:138-150. McHugh, J.L. 1941. Variation of vertebral centra i n young Pacific herring (Clupea p a l l a s i i ) . J.Fish.Res.Bd.Canada 5:347-360. McHugh, J.L. 1954The influence of light on the number of vertebrae in the grunion, Leuresthes tenuis. Copeia (1):23-25. Miller, R.B. and Paetz, M.J. 1953. Preliminary biological surveys of Alberta watershed, 1950-1952. Dept.Lands and Forests 2:1-114. Moore, J.A. 1949. Geographic variation of adaptive characters i n Rana pipiens Schreiber. Evol. 3:1-24. Mottley, G.M. 1934. 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