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UBC Theses and Dissertations

The systematics of the freshwater sculpins of British Columbia. 1957

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THE SYSTEMATICS OF THE FRESHWATER SCULPINS OF BRITISH COLUMBIA by D.E. McAllister A thesis presented in partial fulfilment of the requirements for the degree of Master of Arts. in the Department of Zoology We accept this thesis as conforming to the required standard The University of British Columbia April, 1957 In presenting 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 the requirements f o r an advanced degree at the U n i v e r s i t y of B r i t i s h Columbia, I agree that 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 reference and study. I f u r t h e r agree that permission f o r extensive copying of t h i s t h e s i s f o r s c h o l a r l y purposes may be granted by the Head of my Department or by h i s r e p r e s e n t a t i v e . I t i s understood that copying or p u b l i c a t i o n of t h i s t h e s i s f o r . f i n a n c i a l gain s h a l l not be allowed without my w r i t t e n permission. Department of The U n i v e r s i t y of B r i t i s h Columbia, Vancouver 3, Canada. 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 fin rays, lateral line pores, operculomandibular pores, we ve caudal vertebrae, and preopercular spinesAnoted. Specific descriptions employing these characters were constructed. A new species found by Bailey is reported and described; philonips i s synonomized with cognatus. Intraspecific variation in meristic characters showed modification with habitat, distance from the sea, altitude, latitude, populations and in 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 character- istics. A key is given to the species groups. 1 ACKNOWLEDGEMENTS To Dr. C.C.Lindsey the author is deeply and sincerely grateful for suggesting the problem, for his guidance, suggestions and criticism throughout the study. His extensive collecting has aided greatly in 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 east- ern Cottus. I am also grateful to Dr. W.B.Scott, Dr. E.C.Raney and D r . C.Bond for collections of other species. Dr. G.S.Myers generously loaned specimens of Cottus princeps. 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.Hart- man, J.E.Mason, R.T.Myren, P.R.Nelson, T.G.Northcote and S.Qadri for donation of specimens or aid in collecting. Thanks are given to the X-ray technician at U.B.C. hospital for x-raying specimens. Employment as assistant curator in 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 . . . 5 GEOGRAPHIC VARIATION 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 in different habitats 22 Table 4 . Percent of individuals prickled in each area . . 22 Table 5. Meristic differences between lake and stream populations . . 23 Table 6. Percent of individuals prickled in different areas of the body in coastal and non-coastal populations. 25 Table 7. Frequency distribution of meristics of coastal and non-coastal populations. 26 Table 9. Relation of meristics to altitude in Cottus asper 28 Table 10. Influence of temperature on meristics 29 Table 11. Latitudinal variation in fin ray and vertebral counts . . 31 Cottus cognatus Richardson . 36 Table 12. Latitudinal variation 38 Table Sex differences in meristics . . . . . . . . . . . 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 in Canadian and American Cottus hubbsi . . . . 52 Cottus rhotheus (Rosa Smith) 53 Table 15. Sex differences 55 Cottus aleuticus Gilbert . . . . . . . . . . . . . . . . . . . 57 Table 16a. Comparison of meristics of coastal and non-coastal Cottus aleuticus . . . . 59 Table 17. Latitudinal variation in vertebrae . . . . . . . . . 59 Cottus ricei (Nelson) . . . . . . . . . . . . . . . . . . . . . 61 Table 19. Changes in meristics of Cbttus ricei from southwest to northwest in North America . . 64 COMPARISON OF SPECIES AND INTERSPECIFIC VARIATION 65 Table 20. Meristic comparison of Cottus ricei, C.sibiricus and C. spinulosus . . . 67 Table 21. Number of chin or symphyseal pores 71 Table 23. Numer of individuals of various species having one or two spines on the first dorsal basal . . . . . . 73 Table 24. Number of basals below the dorsal fins . . . . . . . 75 Table 25. Variation in minor caudal rays 76 SUPRASPECIFIC RELATION IN COTTUS . 88 Table 26 Comparative ecology of B.C. Cottus . . . . . . . . . . 89 Table 27. Range of caudal vertebrae . . . . . . . . 91 Table 28. Dorsal spine range in groups I and II . 92 Table 29. Ranges of dorsal rays in groups I and II 93 Table 30. Ranges of anal rays in group I and II 94 &©mU3IQJS 9£ LITERATURE CITED 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 . . . . . . . 82 7. Meristic variation in B.C. Cbttus 86 8. Distribution of B.C.species of Cottus 87 9. Cottus asper and C.aleuticus 101 10. Cottus n.sp_. ,C. cognatus, C. hubbsi 102 11. Cottus rhotheus and °.ricei 103 2 INTRODUCTION The genus Cottus is 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 in characters, such as dentition and number of pelvic fin rays, have been misleading. The variability of populations has led to the naming of -invalid species. Phenotypic and genotypic variation is so great that characters normally used in 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 n intensive study has been made of the 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 is 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 how and vdiy meristics (serially repeated parts) vary. The second describes methods. The third section describes each B.C. species and its 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 in Cottus - a l l species, and terminates in a key. LITERATURE ON MERISTIC VARIATION One of the problems in taxonomy of Cottus has been the lack of knowledge of the variability, and the causes of variability in 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 in fac- tors such as temperature may result in different numbers of fin rays in 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 is summarized in 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 in 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 in the serial characters. It is evident that average temperature, changes in 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 fin rays, dorsal and anal spines, the basals of dorsal and anal rays have shown themselves modifiable. Temperature Most investigators have reared fish at only two temperatures. TABLE I EXPERIMENTAL STUDIES OF MERISTIC VARIATION AUTHOR SPECIES MERISTIC OBSERVED CORRELATION Temperature Bailey and Gosline, 1955 Dannevig, A. 1950 Fox, W. 1948 Gabriel,M.L. 1944 Heuts, M.J. 1947b Lindsey,C.C. 1952 Mottley,C.M. 1934 ibid 1937 Etheo stoma nigrum Pleuronectes platessa Snake - Thamno- phis elegans • atratus Fundulus heteroclitus Gasterosteus aculeatus Marine and freshwater populations Gasterosteus aculeatus Pygosteus pungitius Macropterus opercularus Salmo jgaird- neri Salmo gaird- neri Vert. Vert. Several scale series Vert. D, A, P. Negative Negative Positive D-jbasals, D2 and A basals, C Vert., P. T>2 and A basals Vert. A Vert., A and D2 basals, A spines Lateral line scales Vert. Negative, hereditary Modified differently in two groups and at different salinitie s Positive Negative Lowest at intermediate temp. A l l hereditary Positive Lowest at intermediate temp. Negative Negative Negative Positive and negative 6 TABLE I (continued) AUTHOR SPECIES Temperature Schmidt, J Lebistes 1917, 1919 reticulatus ibid Zoarces 1920 viviparous Tailing, A. Salmo trutta 1952 MERISTIC OBSERVED CORRELATION 2 Vert. Vert. D2,A,P." Positive and hereditary- Modified by salinity of temperature. Lowest at intermediate temp. Highest at intermediate temp. A l l hereditary. Temperature Change Taning, A. Salmo trutta 1946 Light Intensity McHugh, J.L. 1954 Vibert, R. 1953 Leuresthes tennuis Vert. Salmo salar Vert. Vert. Radical effect at 100 day-degrees Negative Partial darkness produced most Salinity Heuts, M.J. 1947b Gasterosteus aculeatus" Marine and freshwater populations D2A,P. Modified differently in two groups and at different temperatures. Other Factors Oxygen concentration Taning, A 1952 Salmo trutta Carbon dioxide concentration Taning, A 1952 Salmo trutta Vert. Vert. Negative Positive D̂  = dorsal spines D2 = dorsal rays A - anal rays P = pectoral rays Negative = negative correlation with factor 7 Frequently unwarranted conclusions have been drawn; e.g., that verte- brae increase with developmental temperature. Schmidt, Taxiing, and Lindsey have shown, using three or more temperatures, that the rela- tionship between temperature and vertebrae is "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 dif- ferences in the number of vertebrae. This effect and the effects of sustained temperature during development suggest great caution be used in the application of meristic characters in 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 in 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. Heuts found that nitrates and phosphates had no effect. It seems likely that the chlorides are the ingrediant causing the differences. Freshwater species might pos- sibly be affected similarly by other dissolved solids. Light McHugh (1954) found that light intensity could influence the number of vertebrae in the grunion, Leuresthes tennuis. Light was found to be more important in determining vertebrae than were temperature and 8 temperature and salinity, the results of which were too variable to anal- yze. 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 in Catostomus catostomus, and the number of somites was affected by light-duration. These experiments are significant because they deter- mine the effect of two factors (day-length and light intensity) which change with latitude. Latitudinal clines in meristic characters, often observed in fish, might be the result of change northward in either of these two factors or both. Interaction It is 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. Lindsey (1952) found that temperature modified the effect of salinity. Other factors also probably interact. Biological Complications Generally speaking, i t becomes colder away from the equator. It is quite possible, however, that fish at different latitudes spawn at the same temperature rather than at the same time of the year. These fish would be exposed to different light conditions. The conditions in which fish "select" to spawn may have a large influence upon the environment to -which the developing egg is exposed. 9 It may be seen that a changing complex of factors change lati t u d - i n a l l y . The effect of biological factors, genetic characters and environmental influences need to be determined before meristic clines are understood. GEOGRAPHIC VARIATION Meristic characters can be correlated with several geographic features. Meristic characters have been shown to change with altitude, latitude, distance from the sea, salin i t y and habitat. These features do not necessarily cause the differences, which may be the result of associated environmental factors (such as temperature). Latitudinal Variation Clines i n meristic characters with latitude are shown to occur i n several species of several families of teleosts i n Table 2. These are merely a sample of numerous instances i n the Literature. Clines exist i n several meristic 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 meristic 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 relationship between meristic characters i n f i s h and latitude. TABLE 2 11 EXAMPLES OF LATITUDINAL VARIATION IN MERISTIC CHARACTERS CLASSIFICATION CHARACTER CLINE LOCALITY SOURCE CLASS TELEOSTOffl Clupeidae Clupea pallasi vert. A & P 35-60°;sw west NA. 30-50°;sw west N.A. McHugh,J.L. 1954 Engraulidae EngrauLis mordax vert. D & A 4- Salmonidae Oncorhynchus tshawytscha McHugh,J.L. 1941 vert. 38-41wjfw west N.A. Osmeridae Thaleichthys pacificus vert. 49-56°;fw west N.A. McGregor,E.A* 1924 Hart & McHugh 1944  Cyprinidae Notemigonus crysoleucas Richardsonius balteatus anal rays anal rays f 28-43 jfw east N.A. 49-55°;fw west N.A. Schultz, L.P. 1926 Lindsey, C.C. 1953  Ictaluridae Ictalurus nebulosus anal rays east N.A. 49-60°;sw west N.A. Hubbs, C.L. 1940 Gadidae Cheragra chalcogramma Syngnathidae mathus californiensis Atherinidae Menidia beryllina D 1, 2 & 3 A 1 & 2 4- 28-60°; sw west N.A. 52_ 26-41°;aw. east N.A. Schultz & Wel- ander 1935 Herald, E.S. 1941 Gosline, W.A. 1248 Percxdae .several species vert. fw; east N.A. Bailey & Gos- line 1955 Clinidae Gibbonsia elegans Stichaeidae Anoplarchus purpurescens Cottidae Leptocottus armatus Cottus asper Cottus rhotheus A & D spines sw; west N.A. D spines sw; west N.A. 0- D2 & A 4, D & caud.vert. ^ r D & caud.vert. sw; west NA. 37-50°;fw west N.A. 1 Hubbs, C.L. 1927 Hubbs, C.L. 1927 Hubbs, C.L. 1921b Northcote,T.G. 1950 1  Cyclopt eridae Liparis liparis Spitzbergen to Norway;sw Vladykov, V. 1224 Pleuronectidae Platichthys stellatus sw;Alaska to California Townsend,L.D. 1937 CLASS REPTLLIA Thamnophis megalops Opheodrys vernalis Thaleophis 4 sp. Cnemidophorus sexlineatus D scales ^ caudal scale s -f ventral scales ^ parietal " ^ Ruthven,A.1908 Grobman,A.1941 Oliver,J.1949 Hoffman,R.1949 Arrow points in direction of decrease of character, north being top, south bottom of page. vert.= vertebrae caud.= caudal D = dorsal rays A - anal rays P = pectoral rays fw = breed in fresh, sw, in 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 in meristics. Geographic clines might well be ex- plained in terms of environmental clines. Average temperature, rate of change of temperature, light intensity, day-length, and light quality a l l change with latitude. All could theoretically affect meristics. It is also possible that geographic clines are hereditary. Lindsey (1953) believed that the latitudinal clines in anal rays of Richardsonius balteatus were genetic. Clines couldbe^due to change in 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 in 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 fin rays in colder water because of its greater density. Possibly metabolic rates or other internal factors are clinal, and these indirectly result in 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. New collections were made (see acknowledgements). Specimens were then selected for study from the larger collections of each species. An attempt was made to cover the range of each species in 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 tip of the upper lip to the poster- ior tip 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 lat- 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 men- tioned by Robins (1954). These extra portions were not counted. Internal Characters To determine internal characters the specimens were stained in alizarin and cleared in 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 pres- ence of palatine teeth, and the degree and extent of prickling were det- ermined. Occasionally fins were damaged in clearing and counts could not be made. This is 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 fin) were noted - one or two. The spines could be distinguished readily from the rays by their slenderness and lack of annulae. The last two rays of the dorsal and anal fins were counted as one when they sat on the same basal. This method was used so that counts from the literature would be comparable. This procedure i s open to some objection, as i t i s actually a basal count rather than a ray count. This would be an understandable method i n groups of fishes where the last ray i s actually branched, but does not differentiate between forms having one or several rays on the last basal. In some species of Cottus co gnatus only one ray occurred on the last basal. The counting method does hot separate these f i s h from f i s h having two rays on the last basal. As one spine was always present i n each of the ventral fins 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 for 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 visually 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 in this paper, caudal vertebrae are referred to, unless otherwise designated. A few counts of abdominal vertebrae were also made. Following McHugh (1941) columns containing abnormal vertebrae were not counted. The number of spines on the left preopercle was- counted. Unless the preopercle erupted into a sharp elevation i t was not considered a spine; low bumps were not con- sidered 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 in Cottus; small spines, termed prickles (see fig. 3) are present in 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 fig. 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 in contact; at 1 they were widely dispersed, only about half a dozen prickles being present in an area. Figure 1. Areas of prickling. 16 Sex was determined by dissection on some individuals. Ovaries are round in cross-section and covered by a definite membrane. Om breaking the membrane eggs can often be seen. Testes are triangular in cross- section and have a white granular composition throughout. Differences are also found in the length of the anal papilla, but this was not used in 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 Insti- tute of Fisheries (see following sample). As the sampling method for these collections was largely seining there are certain limitations to the data. Seining is probably less efficient in 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 in the summer with a few in the f a l l and spring and none in the winter, the data represents only a portion of the year. Since these prejudices were probably random with regard to the species, the inform- ation is nevertheless of comparative value. It indicates relative ecol- ogical differences. Ecological differences are hence discussed under interspecific relationships. Sometimes collections occurred in mixed habitats - rocky and sandy bottom. These collections were entered under both categories. 17 UNIVERSITY OF BRITISH COLUMBIA Institute of Fisheries Field Record Province or Country. Field No County: •. Map: : , 1. Locality: lat N., Long W. Water: - : ... Vegetation: Bottom: Cover: Shore: Dist. offshore: Depth of capture:.. Collected by .1 Tide: Method of capture: Orig. preserv.: 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 in the prints. 18 DESCRIPTIONS OF AND VARIATION IN INDIVIDUAL SPECIES OF B.C. SCULPINS INTRA SPECIFIC VARIATION Cottus asper Richardson 1936 prickly sculpin Figure 9 Synomymy Cottus asper Richardson, Fauna Bor. Amer., Fish., 295, I836 Columbia River at Ft. Vancouver. Trachidermis richardsoni, Heckel, Ann.Wiener Mus., 162, 1840 Centridermichth asper, Richardson, Voyage Sulphur, Icth., 74, 1845; Gunther I860. Cottopsis asper, Girard, U.S. Pacific R.R.Surv., X, Fish., 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, Bull. 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 six vertical saddles, two below spinous dorsal, three below rayed dorsal (see Fig. 9). Dark bar at base of caudal f i n . Narrow dark bands on second dorsal passing posteriorly and ventrally. Irregular wide dark bands on caudal and pectoral fins. Chin and often abdomen covered evenly with fine speckles. Short dark bar under eye bordered by lighter zone. F i r s t dorsal with faint dark cent- r a l band:; prominent characteristic dark spot i n posterior portion; pos- terior dorsal edge with thin 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 fins. See Fig. 9 for the color patterns and external morphological features. 19 Morphology The maximum recorded size is 300 ram. • The usual maximum i s 150 mm. The head i s large and the mouth is only smaller than that of Cottus rhotheus (of B.C. species) (discussed by Northcote 1954). The caudal peduncle is of medium depth. Strong teeth are present on the palatine bones but these do not come into contact with the vomerine patch of teeth. As in 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 is a small bump, while that of the male is a large flat- 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 is very variable in extent and intensity. Some have only a few in the axil 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 in a l l regions in Fig. 1 (regions a - j ) . Generally they are most dense in regions b to e and decrease in intensity outwards. The prickles themselves are generally large and strong, have a long sharp shaft and a flat or tridentat base (see Fig. 3). One pore is usually present on the tip of the chin (see Fig. 5). 20 Meristic values (vertebrae and f i n rays) may be obtained from the section on interspecific comparisons or from Fig. 7. S t a t i s t i c a l sig- nificance of meristic differences i n the graph (Fig. 7) may be determined visually (graphical method from Hubbs and Hubbs (1953)« The f i r s t two dorsal spines are usually placed on the f i r s t dorsal basal. Usually the last spine and the f i r s t dorsal ray are placed on their own basal (67 specimens), occasionally they are on the same basal (9) and rarely an unrayed basal exists (6). The ventral f i n almost invariably contains 4 rays, only two specimens being found with 5 and two specimens with 3 rays out of many examined. The innermost ray i s about % the length of the longest. The lateral line i s usually complete i n specimens over 60 mm. i n length. Sometimes the lateral line i s missing on the caudal peduncle and i n specimens from Buttle Lake i t extends only to the mid- dle of the rayed dorsal. The number of pores in specimens over 60 mm. may vary from 32 to 43 but i s usually about 3#. No external scales exist. Internal scales were apparent between the l a t e r a l line pores i n cleared specimens of a l l species. These internal scales are hollow tubes which surround and presumably support the l a t e r a l line canal. Tiny holes appear at the bottom of these tubes which may transmit nerves or blood vessels. Internal scales develop as the lateral line forms and are usually about equal to the number of pores. Illustrations of similar structures may be seen i n Bolin (1952). Distribution Figure $ gives the distribution 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 California - 34°20». Most Pacific 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 into 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 well as many coastal lakes and streams. GEOGRAPHIC VARIATION The number of body parts i n £. asper have been found to vary with geographical factors. As the number of parts i s taxonomically s i g n i f i - cant i t is important to know the existance and extent of effects geography may have on meristic 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. Prickling was found to be one of the most variable characters i n the prickly sculpin. Some individuals are so densely prickled that the bases of the prickles are almost i n contact, while i n others the prickles are far apart. The extent as well as density varies widely. To deter- mine i f habitat had any influence on the variability, the intensity of prickling 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 for habitat classification. Following are tabled the means for 22 intensity of prickling for each region on the body. The percent of individuals which possessed prickles i n each region is also tabled. The number of individuals and number of collections i s included. TABLE 3 MEAN INTENSITY- OF PRICKLING IN DIFFERENT HABITATS (in Cottus asper) HABITAT AREA PRICKLED N M a b c d e f g h i j Mean River .16 7 .60 1.1 3.1 2.8 3-1 1.2 .71 .62 2.2 .49 1.6 Lake 94 28 .571 1.68 2.53 2.22 2.47 1-32 .692 -531 1.82 .391 1.42 Brackish 15 3 .00 1.5 2.4 2.3 2.2. .47 .07 .00 1.9 .00 l.iJfi N = number of individuals M = number of samples TABLE 4 PERCENT OF INDIVIDUALS PRICKLED IN EACH AREA FROM DIFFERENT HABITATS (Cottus asper). HABITAT AREA PRICKLED N M a ,-b c d e f g h i j Mean River 16 7 56$. 94$ 100% 100% 100% 88$ 50% 44$ 94$ 38$ 76.4$ Lake 94 28 48$ . 100$ 100$ 94$ 94$ 86$ 57$ 53$ 89$ 35$ 75.6$ Brackish 15 3 0$ . 100$ 100$ 100$ 93$ 47$ 7$ 0$ 93$ 0$ 54.0$ 23 The preceding tables indicate differences i n prickling between ha- bitats. Six out of eight of the areas on river sculpins were more heavily- prickled than those on lake sculpins. A l l but one of the zones on the brackish sculpins are less prickled 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 prickled over less of the body than the river specimens, while the brack- ish specimens are much less prickled than either. A large difference between both lake and stream and the brackish sculpins i s that the brack- ish ones lack prickles on the head, beside the rayed dorsal, and below the lateral line on the caudal peduncle. Robins (1954) found similar differences i n Cottus carolinae which was less densely prickled i n lakes and most densely prickled i n torrential rivers. 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 lac- 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 parenth- eses. HABITAT NO. DORSAL DORSAL" ANAL PECTORAL VERT. BRANCH LOCALS • SPINES . RAYS RAYS RAYS Rivers 16 . 9.08(83) 20.69(77) 16.92(78) 16.44(81) 26.00(101) 6.12(88) Lakes 94 8.93(217) 20.70(214) 16.60(204) 16.59(203) 25.81(240) 6.30(181) 24 It vdll be noticed that there is almost no difference in 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 gills. Aim (1952) found that heritable dif- ferences were present between lake and stream populations of Salmo trutta. It is also possible that the differences between lake and stream sculpins are caused by differences in developmental conditions, rather than en- vironmental selection. Coastal and Non-coastal populations It will be noted that the greatest morphological differences occurred between brackish and freshwater populations. This classification of environments is very coarse, only separating those individuals living close to or in 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 in- cluded. About, equal number in the two groups were chosen from different 25 latitudes. Table 6 below gives differences i n prickling. 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 (in Cottus asper) HABITAT AREA PRICKLED a d e f g h i j Mean Coastal (52) 0$ 83$ 77$ 35$ 29$ 23$ 63$ 13$ 40.3$ Non- coastal 69$ 91$ 94$ 91$ 77$ 86$ 91$ 77$ 84.5$ (35) Sculpins l i v i n g near the sea are evidently less commonly prickled i n several body areas than sculpins l i v i n g away from the sea. This i s highly significant s t a t i s t i c a l l y . The prickles were also observed to be closer together i n the non-coastal forms. Probabilities of the s i g n i f i - cance of difference of prickling i n different areas i s given below. Area P Area P a <.001 g <.C01 d .2-.1 h <.001 e .05-.01 i ,01-.001 f <.001 Meristic differences between coastal and non-coastal populations of the prickly sculpin were also analyzed. Data is presented i n the following table. 26 TABLE 7 FREQUENCY DISTRIBUTION OF MERISTICS OF COASTAL AND NON-COASTAL COTTUS ASPER LOCAL DORSAL DORSAL RAYS ANAL RAYS PECTORAL VERTEBRAE SPINES RAYS 8 9 10 19 20 21 22 23 15 16 17 18 15 16 17 24 25 26 27 28 Coastal 4 69 7 2 22 47 7 1 0 14 50 16 12 49 19 1 11 55 14 0 Non- Coastal 10 53 5 3 15 33 17 0 3 9 43 12 2 23 42 0 2 28 32 2 Chi square tests showed that the probability 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. Because of the similarity of anal ray counts they were not tested. The differences between coastal and non-coastal populations i n dorsal rays, pectoral rays and vertebrae are too great to be attributed to change. It has been shown that differences i n extent and intensity of prick- ling and i n numbers of dorsal rays, pectoral rays and vertebrae, between coastal and non-coastal prickly sculpins are significant. What has caused these differences? Biological data must be considered before this can be answered. According to Shapovalov and Taft (1954), prickly sculpins migrated downstream to spawn through a counting fence close to the sea at Waddell Creek, California. Sumner (1952) reports that Cottus asper were caught in their downstream trap, which was just below the head of tidewater, i n spring and early summer - the spawning period at Jewell Creek, Oregon. Hunter (pers.comm.) states that Cottus asper moves into the intertidal 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 in under fresh water in 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 is unlikely that inland sculpins would migrate long distances to the coast to spawn, and i t is known that populations 50 miles from the sea spawn in 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. Secondly, the differences could be heritable. Coastal forms migrate downstream to the sea. One would also expect several necessary adaptions to accompany this behaviour. Physiological adaptions would be necessary in 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 in 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 morpholo- gical differences. All 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 fresh- water form. As the morphological differences overlap i t is unlikely that they are. completely reproductively isolated. 28 Altitude All 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 in Table 9, below. TABLE 9 RELATION OF ALTITUDE TO MERISTICS IN COTTUS ASPER Mean is followed by sample size in parentheses. ALTITUDE DORSAL DORSAL ANAL PECTORAL VERTEBRAE SPINES RAYS RAYS RAYS 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 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 intensity of insolation increases with altitude. Changes i n the components of light also take place, with ultraviolet and infrared intensity increasing upward. The differences in meristics at different altitudes could be attributed to developmental or selective effects of these factors. Temperature Temperature has been shown experimentally to modify meristic charac- ters. It was decided to test i t s effect i n nature. Unfortunately temper- ature data are not available i n the most desireable form for correlation. Ideally spring temperatures - those during spawning times, would be the most logical to correlate with meristics. However, the only available isotherm maps are July or January. July was chosen as the most suitable. It is assumed that July temperatures are related to those i n the spring and that there i s a direct relation between a i r temperature and water temper- ature. Table 10 gives mean July temperature and the means of vertebrae and f i n ray counts. TABLE 10 INFLUENCE OF TEMPERATURE ON MERISTICS Mean July Temperature, meristic mean and sample size (in parentheses) of B.C. Cottus asper AVERAGE JULY DORSAL C " . DORSAL ANAL PECTORAL VERTEBRAE ISOTHERM SPINES RAYS RAYS RAYS DEGREES F. 70° + 8.87(31) 20.41(32) 16.56(32) 16.81(27) 25.28(29) 70°.- 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 in dorsal spines with increase in temperature, except at the lowest temperature. Rectoralsrays show an opposite relationship. Vertebrae and anal rays are highest at inter- mediate temperatures. V-shaped relationships to temperature were found in other species by Lindsey (1952) and Taning (1952). Although several of the differences are probably statistically different, no simple pat- tern is apparent. Latitude Below is 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 LATITUDE DORSAL . DORSAL ANAL PECTORAL VERTEBRAE SPINES RAYS RAYS RAYS 38°N 8.34(59) 19.78(59) 16.36(59) 16.05(59) 40 8.70(20) 19.80(20) 16.67(20) 16.1 (10) 25.30(59) 8.73(49) 16.78(49) (California) 42 20.34(50) 15.80(44) 44 8.98(46) 20.98(46) 17.20(46) 16.33(46) 26.06 > 9.03(29) (Oregon) 46 21.04(28) 17.14(28) 15.89(19) 48 8.92(25) 20.40(25) 16.72(25) 15.53(15) 26.00 (Washington) 50 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) 16.86(28) 25.77(26) 54 9.15(41) 20.48(44) 16.63(43)' 16.95(39) 25.49(57) 56 9.11(71) 20.23(60) 16.68(65) 16.44(73) 25.50(64) 58 9.0 (4) 22.2 (4) 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 in pectoral rays but the oscillations are so great that the tendency to increase northward is 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 pop- ulations from different temperatures, altitudes and latitudes, i t will 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. The pectoral rays and dorsal spines bear no such relationship. 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 r sample size p dorsal spines x vertebrae -.00956 188 ^.05 dorsal rays x vertebrae .278 187 <C.01 anal rays x vertebrae .172 179 .05-.01 pectoral rays x vertebrae .0332 180 >.05 The above indicates that there is 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 is 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 in development by similar effects of environmental factors on these characters. Comparative Variability of Characters. It is convenient in 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 is .508, for dorsal rays .704, for anal rays is .722, for pectoral rays i s .686, principal caudal rays .208 and for verte- brae .729. The size of the standard deviation depends upon the size of the mean, however. A comparable measure of dispersion is obtained i f one multiplies the standard deviation by 100 and divides by the mean. This is called the coefficient of variation. The coefficient of variation for dorsal rays is 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 environ- mental changes. Two, the degree of constancy is genetic. Here, the low variability of some characters is advantageous and has been selected for. Selection could make characters less variable by favouring development of the character at an earlier stage in morphogenesis. Vertebrae probably develop earliest of meristic characters. The probable order of development of rays in.Cottus bairdi kumlieni (Marie Fish 34 1932) is fi 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 in 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 is 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 is also interesting to note that the caudal rays and vertebrae which are probably most important in locomotion develop earliest and are least variable. The spinous dorsal fin, which probably has mainly a behavioral function, develops last and is the most variable. Year Class Variation No comparisons were made of year classes. Northcote (1950) found no difference between year classes zero and one in dorsal spines and rays. A significant difference was found in 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 in Cottus asper. DISTINGUISHING CHARACTERISTICS The prickly sculpin is distinguished from a l l other B.C. forms by its complete lateral line, palatine teeth, single symphysial pore, 24-28 35 caudal vertebrae and distinct round black spot in 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 in 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. Second dorsal, caudal and pectoral with bands on rays forming bars. The spinous dorsal of male in spawning season dark to black, particularly anteriorly and posteriorly, with broad orange edge. Male generally dark a l l over in spawning season. Dark patch beneath eye and between eye and preopercle.(see Fig. 10). Morphology Maximum size in British Columbia 120 mm. Head small, 3-0-3.9 into standard length; mouth small. Caudal peduncle deep, 3.2-4*4 in head, usually 3.5-4.2. Posterior nostrils not tubular. A n a i papilla begins to be longer in male after a total length of about 60 mm., until at 80 mm. i t is twice as long as female's - about 2 mm. It has a long flat "V"- shape in the male while in the female i t forms a small round extension. One, two or three preopercular spines may be present. Prickles are re- stricted to a weak patch in the axil. The prickles are usually of in- tensity 1 above the lateral line and of 1 or 2 below. The number of 37 prickles above the lateral l i n e varies from 0 to 5, usually 1 or 2, and varies from 0 to 86 below, usually about 40 to 50. The prickle shaft i s equal or longer than the length of the base. The base of the prickle i s oval (see Fig. 3). The skin is slippery, hence the name slimy. Two pores are present on the t i p of the chin, one on either side of the symphysis. Usually (in 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 si t s on the last anal basal or one tiny ray i s bound to the larger so as only one i s dis- cernable i n the uncleared fish. 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 lateral line i s always incomplete and usually ends before the second third of the rayed dorsal. It usually contains 18-22 pores (rarely 12-25) i n specimens over 60 mm. total length. DISTRIBUTION Cottus cpgnatus i s the most widely distributed of North American fresh- water sculpins (see distribution, Fig. 8). It occurs on the eastern sea- board as far sbuth as Virginia, i n the Labrador Peninsula, the Great Lakes, i n northeastern Iowa and Minnesota. It i s apparently absent from most of the Saskatchewan system, but i s present i n the North West Territories and Alaska from the Arctic Ocean to Kenai Peninsula. In British Columbia i t occurs i n the Yukon, Stikine, Mackenzie, Fraser and Columbia River systems. Distribution records were obtained from Eddy.and Surber (1947), Livingston (1952), Hubbs and Laglar (1949), Dymond (1947), Walters (1955), Iindsey (1956), Carl and Clemens (1953), Miller 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 in 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 is 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 in the Institute of Fisheries Museum. TABLE 12 LATITUDINAL VARIATION IN COTTUS COGNATUS Mean and sample size (in parentheses) LATITUDE DORSAL DORSAL ANAL PECTORAL VERTEBRAE SPINES RAYS RAYS RAYS 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) 21.90(10) 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) 15.6 (5) 10.4 (5) 13.4 (5) - 70 8.3 (12) 15.5 (12) 11.3 (12) 13.3 (13) 21.7 (9) The foregcmg table demonstrates several clines. An unidirectional cline is found in anal rays in 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 cline. The remainder of the counts, dorsal spines, dorsal rays, pectoral rays and vertebrae a l l tend to show a double cline, decreasing away from 54°. The condition over most of the range (from 54-70°) i s a decrease northward. The significance of the double clines i s discussed under river systems. River System Variation The greatest differences i n meristics between latitudes occurred from 54° to 56° (Table 12). These latitudes coincide with the Peace and Fraser Rivers. To determine the amount of variation attributable to river systems the data were reclassified. The mean dorsal spine, dorsal, anal, ventral and pectoral ray counts for the major of B.C. are given i n Fig. 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 ventral 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. The Ne-parle-pas Rapids are probably impassable to fi s h . It i s interesting to note that Cottus. r i c e i , Percopsis omiscomaycush, Stizostedion vitreum and Platygobio gr 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 Liard. The lower Peace, Liard and Stikine 40 specimens (referred hereafter as Northern) never have three ventral rays, while the upper Peace, Fraser and Columbia (hereafter referred to as Southern) frequently have three ventral rays. None of the Alaskan speci- mens have three ventral rays. 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 that the upper and lower Peace are not climatically different would suggest the differences be- tween them are not the result of environmental influences. The small sample size of the lower Peace collection should be noted. The constant presence of a fourth ventral ray, however, would confirm the low alliance 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 ratio i n Cottus cognatus from the different river systems. Mean Range Sample Alaska 4.13 3.8-4.8 7 Liard River 3.93 3.4-4.7 18 Lower Peace 3-89 3.6-4«4 10 Upper Peace 3.63 3.3-4.1 20 Fraser River 3.59 . 2.9-4-3 17 Columbia River 3.70 3.4-4-2 16 It w i l l be seen again that there "is a break between the upper and lower Peace and that this difference is.greater than that, between the upper Peace and the Fraser. In fact, 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 significant Stikine River «13 i i i i Liard River £ 27 \ \ '.' ' ' ,: \ \ . Lower Peace River & 10 Upper Peace River O 17 Fraser River Columbia River 6 38 v O 76 8 9 Dorsal Spines • 13 • 27 9 13 27 * 1 1 0 * 10 Ne-parle-pas Rapids ON .20 N N N \ *038 6 78 O, 19 •3 / / \ •8 P 20 O 38 <3 32 i d 75 <>66 16 17 11 12 3 4 Dorsal Anal Ventral Rays Rays Rays NUMBER OF RAYS Number beside point is sample size • 14 V*5 9 19 ?37 67 13.5 14.5 Pectoral Rays FIGURE 2. Means of Fin Ray Counts in 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 in 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 in the southward displacement of these sculpins until they were present in 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 in the Columbia system. When the glaciers retreated, cognatus might well have followed northward. It is likely that in 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 in the bend of the Fraser i t is 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 is apparently the only like- ly means of transmission between the two systems (see Figure 2a). From similarities between the upper Peace and the Fraser, i t would seem likely 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 is demonstrated by the presence of Cottus asper in the upper Peace, where its present restricted distribution strongly suggests entrance from the Fraser. Probable movements of cognatus following glaciation in B.C. are given in Figure 2a. Figure 2a also compares Stikine populations with other systems. The differences would indicate that the Stikine is more dissimilar to the Fraser than to the Mackenzie. The Stikine has the high ventral fin ray count of the Northern forms. It seems likely 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 in Alaskan derived types, the con- tinuity of meristics and proportions in the {Northern and in 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 in Table 13, below. The sample includes specimens from the Liard, Fraser and Columbia. 44 TABLE 13 SEX DIFFERENCES IN MERISTICS OF B.C. COTTUS COGNATUS SEX Dx D2 A 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. No sig- nificant differences were found. It is 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 in the snow waters of the Kicking Horse River (Columbia system) in southeastern B.C. These were named in the same year as Cottus philonips. 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 Head into standard length Depth Dorsal spines Dorsal rays Anal rays Palatine teeth Preopercular spines 4-4̂  or 3.8 6.0 8 - 9 16-18 11-13 Absent 1 Cottus cognatus 3-0-4.0 -4.6-6.2 8-9 (rarely 7-10) 16-18 (15-19) 10-13 Absent 1-3 45 The description of color in Eigenmann (1892) and Jordan and Evermann (1898) agrees very well with that of cognatus. According to the key in 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 is common to have the prickles reduced to less than a dozen. The prickling of philonips is not, therefore, outside the range of that of cognatus. The position of the tip of the maxilla, tip of the pectoral and of the anus mentioned in the original description do not serve to differentiate the two. The last six of the characters in the preceding table do not show reason for differentiation. Eigenmann's statement about the head is the only one not in agreement with cognatus. Eigenmann (1892) states, "Head proportionately longer in adult, about 4̂ -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 4̂ -4 times, which is i l - logical. Standard length does not enter 4̂ -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 in standard length, so they must have been sure of this character. Although fairly extensive collections have been made in the upper Columbia River, and one in Emerald Lake near the type locality (about 5 miles from i t ) no sculpins have been found having 4 to 4̂  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 in de- scribing the head. Hence, because no other differences have been found, I would consider philonips synonomous witb. cognatus. ^ottus cognatus has priority. In the event that philonips should prove to be a distinct form, i t will 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. Three light mottled saddles under second dorsal. Chin evenly speckled. Pectoral, dorsal, and caudal fins with mottled crossbars. Dark medium band in fir s t dorsal fin, more intense anteriorly and posteriorly. Edge of fin light in preserved males. 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. Body stouter than other B.C. species. Head short, round from above, 3.2 - 3.7 times into standard length of B.C. specimens. Tail short. Caudal peduncle deep, 3.2 - 3.6 times into head. Palatine teeth present, but weak, not in contact with vomerine teeth. Posterior nostrils g'emitubular. Anal papilla longer in male. Preopercular spine at corner of preopercle with one below and sometimes a small projection underneath (2 below in some U.S. specimens according to pers. comm. from Bailey). Prickles in weak patch behind pectoral fins or absent. Two sympheseal pores are present. One spine on the first dorsal basal in a l l five specimens examined. Inter-dorsal spines and rays each on own basal with no empty inter- 48 dorsal basals in those examined. Ventral fins 14 in 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 in specimens over 60 mm. About a dozen of this species were collected in the Flathead River of the Columbia system in southeastern British Columbia, along with Cottus cognatus (which was more numerous). -*-t was designated as Cottus bairdi punctulatus (Gill) with which i t agreed in several characters and disagreed in others, It also showed some similarities to Cottus bairdi semiscaber. 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 in Idaho, northeastern Oregon and eastern Washington. He in- tends to give a brief synopsis of American representatives of Cottus within the year, in which he will name the new species. Because of its small head, i t will be referred to as the shorthead sculpin in this thesis. As the shorthead sculpin is present in only one river system in British Columbia and as no other published data exist oh i t , no discus- sion of its variation will be given. DISTRIBUTION The shorthead sculpin occurs in the Salmon River in Idaho, in the Columbia system in northeastern Oregon and in eastern Washington. In British Columbia i t has been found only in the Flathead system. 49 DISTINGUISHING CHARACTERISTICS The shorthead sculpin is distinguished by its 2 chin pores, incom- plete lateral line ending before the termination of the second dorsal, palatine teeth and its short head and one or two preopercular spines. It is 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. Three dark saddles under the second dorsal f i n . Rays of dorsal, caudal, pectoral and often anal with broad dark bands. Dorsal f i n in breeding male possesses a dark median band; in preserved fish the edge is devoid of pigment, but possibly i t may be colored in fresh specimens. Orange flash on flanks. In non- breeding males and females the median band is reduced to dark areas in the anterior and posterior parts of the fin. The chin and less so the abdomen is sprinkled with fine black spots. Two eye bars, similar to those in Cottus asper, are present. Morphology The maximum size yet found is 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 is 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 in 51 adult male. Three preopercular spines present. Prickles usually present behind pectoral fin, stronger below lateral line. Occasionally prickles extend onto in front of the dorsal, beside the rayed dorsal or onto the dorsal surface of the caudal peduncle. The unprickled portion of the skin is 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 first ray on their own basal as had an empty basal. The lateral line is nearly always incomplete, missing on the caudal peduncle-.. It contains about 28 to 36 pores, rarely 23 to 38 in specimens over 60 mm. DISTRIBUTION Cottus hubbsi is limited', as far as is known, to the Columbia River system. It is found in Idaho, Washington and British Columbia, -*-ts distribution in B.C. may be seen on Figure 8. Distribution in U.S.A. is 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 in Table 16. 52 TABLE 16 MERISTIC DIFFERENCES IN CANADIAN AND AMERICAN COTTUS HUBBSI LOCAL Dx D2 A P 7 '8 16 17 18 11 12 13 14 13 14 15 16 British Columbia 8 13 1 16 4 10 10 1 5 21 16 Washington 13 27 2 30 8 4 19 15 1 1 9 27 3 & Idaho 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 be- tween 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. is significant. Bailey and Dimick included counts of both right and left pectoral rays, while mine included only those of the left. It is possible the difference is attributable to bilateral differences. DISTINGUISHING CHARACTERISTICS The Columbia sculpin is distinguished by 2 symphisial pores, evenly speckled chin, palatine teeth, axillery prickles and lateral line ex- tending 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 fin and often anal fin with .bars on rays forming bands. Speckles on the pectorals may form vague bands. The rim of the spinous dorsal fin is thickened and colored orange in the spawning male; the base may be dark. The chin, unlike other B.C. species is strongly mottled (see Figure 11). Often the ventral surface of the body is 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 in head. Strong palatine teeth, band usually in contact with the vomerine teeth. 54 Pyloric cacae 4-5. Posterior nostril semitubular. Anal papilla long and narrow in male, short and tubular in female. Three preopercular spines'. 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 fin. Occasionally, according to Bailey and Dimick (1949) the prickles are much reduced. Each prickle has a large oval base which is equal to or greater than the height of the spine (see Figure 3). The proximal portion of the base is usually serrated. Two symphysial pores are present. The skin of the lower mandible is wrinkled. Usually one spine is 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 is usually complete and often extends onto the caudal fin. 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 is reportedly found in British Columbia, Wash- ington, Oregon and Idaho, in the Columbia and Kootenay Rivers, and in Puget Sound drainages Nehamlem River, Oregon. This is the distribution given by Schultz and Delacy 1936. It is possible their localities contain Cottus hubbsi with which C. rhotheus has been con- fused. For this reason I have only given B.C. distributions, where id- entity is certain, on Figure 8. 55 SEX DIFFERENCES The following table combines Northcote's (1950) and my data on sex differences in Cottus rhotheus. TABLE 15 SEX DIFFERENCES IN COTTUS RHOTHEUS, A COMPARISON OF MERISTICS. SEX D l D2 A P Vertebrae 7 8 9 14 15 16 17 11 12 13 15 16 21 22 23 Male - 6 16 - 6 13 2 4 17 1 - 7 7 8 1 Female 2 9 23 2 8 17 6 12 22 1 2 11 14 16 - A chi square test on the largest difference between sexes in 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 in dorsal rays between samples from both Idaho and the Columbia River and the Arrow Lakes was significantly different. The increase in vertebrae from Oregon to B.C. was significant! 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 consider- able 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 fin base, and the prickles on the body much 56 reduced or sometimes completely absent. The last condition is similar to that found in coastal populations of Cottus asper. Cottus rhotheus has not been recorded as entering brackish or salt water, however. DISTINGUISHING CHARACTERISTICS Cottus rhotheus is distinguished by its 2 sharp dark dorsal saddles, its highly mottled chin, i t s strong palatine teeth which touch the vomers, and the two pores on the tip of its 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 in Cottus. Cottus aleuticus Gilbert, Rept. U.S.Fish.Com.,XIX, 418, 1893, streams at Unalaska; also in Departure Bay, Vancouver Island. DESCRIPTION Color Color grey with dark blotches, underparts white. Three mottled saddles under second dorsal. 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 first dorsal fin when spawning. Chin covered evenly with fine speckles, unwrinkled. Often orange splotch at basd of pectoral fin 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. wo teeth on palatine bones. Posterior nostrils distinctly tubular, inclined posteriorly. Anal papilla longer in male than in 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 is 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 in 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 in Pacific drainages from Carmel River, just south of Monteray Bay, California - 36° 50' N, to Unalaska, Alaska at the western tip 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 in the Skeena system. See Figure 8 for distribution. GEOGRAPHIC VARIATION Coastal and Non-coastal As coastal population of Cottus aleuticus have shown downstream spawn- ing migrations in Waddell Creek, Californis (Shapovalov and Taft 1954) similar to those in 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 Dx D2 A P VERTEBRAE 8 9 18 19 20 12 13 14 15 13 14 15 16 24 25 26 27 Coastal 5 17 4 14 3 0 1 1 9 1 3 12 7 0 1 4 9 1 Non- Coastal 9 17 5 22 3 1 12 12 2 2 8 15 2 0 2 17 3 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 sev- eral differences to arise i f separate populations existed, the differences could be attributed to environmental factors. Data on 35 specimens indi- cates no difference in 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 speci- mens . Table 17 below shows latitudinal variation of Cottus aleuticus. TABLE 17 LATITUDINAL VARIATION IN VERTEBRAE OF COTTUS ALEUTICUS Latitude Number of Caudal Vertebrae 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 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 D̂  I>2 A P VERTEBRAE 8 9 10 18 19 20 12 13 14 15 13 14 15 16 24 25 26 27 Male 3 11 1 3 10 2 0 6 9 0 2 5 4 4 - 1 9 3 Female.10 25 14 23 2 2 23 13 2 3 29 6 1 1 4 10 Chi square tests were applied to the data which showed signs of dif- ferences - vertebrae, pectoral and anal rays. Only pectoral rays were found significantly different. The males had significantly more pectoral rays, p.05-.02. The explanation of this might be found in the behavior of the male. The male in Cottus gobio, the English sculpin, has been found to fan the eggs with undulations of his pectoral fins. This activity oc- curs during incubation until just after hatching. Similar behavior has been observed in Cottus asper by the author. Possibly the increased number of rays is associated with egg-fanning activity in Cottus aleuticus. It is interesting to note that, although the differences were not signifi- cant, more pectoral rays were found in male Cottus cognatus and rhotheus. DISHNGUISHING CHARACTERISTICS Cottus aleuticus may be distinguished by its tubular nostrils, single preopercular spine, 24 to 27 caudal vertebrae and single symphysial pore. 61 Cottus ricei (Nelson) 1876 spoonhead sculpin Figure 11 Synonomy Cottopsis ricei 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 ricei Jordan and Gilbert, Bull.U.S.Nat.Mus., 16, 953, 1883 Uranidea spilota Jordan and Gilbert, Synopsis, 694, 1883, not of Cope. Uranidea ricei, Jordan and Gilbert, Synopsis, 953, 1883. Cottus pollicaris Jordan and Evermann, Bull.U.S.Nat.Mus., 47, 1954, 1898. Cottus ricei 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. Four pyloric cacae. Post- erior nostrils semitubular. Upper preopercular spine curved upwards and inwards in 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. Strongly prickled individuals often have more preopercular spines. The prickle has an oval base which is longer than the spine. The long base is strongly serrate on the side distant from the spine (see Figure 11). One symphysial pore 62 is present. Meristic variation in Figure 7 includes specimens from over the whole North American range (other species counts just from B.C.). Twelve specimens had one spine on the first dorsal basal, two had two. Out of 15 specimens one had three empty basals between the dorsals, one had two empty basals, four had one empty basal and in six a l l the interdorsal basals were occupied by a spine or a ray. The lateral line is usually complete at a total length of 55 mm. When complete i t contains from 35 to 37 pores. DISTRIBUTION The spoonhead muddler is found in the Great Lakes system, in James Bay drainages, i n the North Saskatchewan River, i n Lesser Slave Lake and tributaries, in Lake Athabaska, in Great Slave Lake, in the Peace River and i n the Muskwa River of the Liard system (last two in B.C.) and in 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 in these areas. GEOGRAPHIC VARIATION As only two collections of Cottus ricei have been made in British Columbia, the literature and museum collections from other locals have been relied on. Table 19 shows latitudinal variation in Cottus ricei 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 in Table 19. Despite this small sample size trends are apparent. The number of anal rays decline northward. The pectoral and dorsal rays probably also decline northward, while the dorsal spines perhaps increase northward. The distribution of Cottus ricei is,disjunct, a northwest and a southeast region being populated. Significant differences probably exist in 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 clinal problem in taxonomy. The distribution of ricei looks almost as i f the original distribu- tion was continuous and had been cleaved by glaciation.- If this is so, where did the northwestern group survive? It i s not known to be present in Alaska (Walters 1955). It is 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 is possible that the spoonhead sculpin has remained undiscovered in the intermediate regions. TABLE 19 CHANGES IN THE MERISTICS OF COTTaS RICEI FROM SOUTHEAST TO NORTHWEST IN NORTH AMERICA. DORSAL SPINES DORSAL RAYS • ANAL RAYS PECTORAL RAYS VERTEBRAE 7 8 9....10 16 17 18 19 11 12 13 14 15 16 14 15 16 17 23 24 25 Lake Erie 1 1 1 1 Lake Huron and 5 5 1 1 6 3 1 3 7 1 2 7 1 1 Lake Michigan Lake Superior 1 1 1 1 Lake Nipigon c c r c c c ON North Saskatchewan 1 1 1 1 1 •p" Peace River 1 1 1 1 1 1 1 1 1 1 Muskwa River 7 1 1 1 6 2 8 1 8 1 4 5 Lesser Slave Lake 2 1 1 2 1 1 1 1 Great Slave Lake 2 2 1 1 2 1 1 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 in vertebral counts, chin pores and the number of spines on the first basal of the spinous dorsal fin. 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 in body proportions, dentition, coloration of spinous dorsal of spawning male and prickling. Probably this resemblance is secondary - an example of the common convergent evolution in the group. The shorthead sculpin resembles hubbsi and cognatus in several respects. It differs from cognatus in dentition, in which i t resembles hubbsi. The opercular mandibular pores in cognatus agree in number and pattern with the shorthead and differ from hubbsi. More study wil l be required to det- ermine the exact relationships. C.aleuticus bears many affinities with Cchamberlini and protrusus which are discussed in Schultz and Spoor (1933) in which reference protrusus was named:. The similarities are numerous and the differences few and in- vestigation might show synonomy. Crhotheus has many affinities with C.ricei. Their wrinkled chin, prickling and prickles, narrow caudal peduncle, wide flat head, preopercular 66 armature, complete lateral line and serai tubular nostrils are common features. C.rhotheus is distinct from ricei in 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 is possible that rhotheus is a modified relict of ricei from some past glaciation. C.rhotheus is somewhat similar to C.carolinae in mottling and wrinkling of the chin, speckling on the pectoral fins, and two sharp saddles under the second dorsal, in having the vomerine and palatine teeth in contact, and in having two symphysial pores. It differs from carolinae in prickling and possession of a reddened dorsal in the spawning male, in having a com- plete lateral line. C.rhotheus is probably also similar to the unpublished new species of Robins, C.girardi„having the same characters in common that carolinae has, except the number of symphysial pores. C.rhotheus is geographically quite isolated from carolinae and girardi, both being east- ern forms. C.rhotheus seems to have more characters similar to carolinae than to ricei, hence should be considered most closely related to i t . It i s interesting to note that the characters in ricei that are similar to rhotheus are net usually those in carolinae that are similar to rhotheus; each is -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 in 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 in Berg's illustrations appear very similar to ricei. A dorsal viewoof the head of 67 sibiricus shows the same wide head and hornlike upper preopercular spine as in 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 SPINES DORSAL RAYS ANAL RAYS PECTORAL RAYS LATERAL PORES ricei 7-10 16-19 11-16 14-16 35-37 sibiricus 7-8 17-19 12-14 15-16 spinulosus 7-8 16-18 12-14 14 32-35 The pectoral ray counts of sibiricus are taken from illustrations, and hence may not be accurate. It wi l l be seen that none of the meristic ranges has sufficient distinctiveaess to provide separation, except lat- eral line pores. This demonstrates their close relationship. It is interesting to note that C.ricei keys down to C.sibiricus in 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 ricei is a close relative of sibiricus. The wide separation (neither species in Alaska and sibiricus only as far west as the Kolyma River in western Siberia) raises the question of how, i f related, they arrived at their present distribution. 68 INTERSPECIFIC DIFFERENCES Interspecific differences will be dealt with by discussing differ- entiating characters and evaluating! their taxonomic worth. Relative Gro wth Body proportions have been utilized l i t t l e in 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 in separating forms such as hubbsi and rhotheus. A sufficient series of representative measurements must be utilized, unlike has been done in the past where single specimens have sufficed. Ths position of the ventrals relative to the anus, often used in the past, does not seem to be a valuable character in B.C. species. The proportion of depth into length does not seem a valuable one as i t is 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 is useful in the field. 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 in Cottus surviving preservation and useful in 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 fin, and mottling on the chin. Sexual differences in 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 in 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 in some popula- tions of cognatus and absent in others. Whether the palatine tooth patch was in contact with the vomerine teeth was found to be a good character. The number of pyloric cacae in 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 is usually valid in separating those with non- tubular and tubular nostrils, however. Preopercular spines are a highly modifiable character in the genus Cottus and within some of i t s species. In asper and the shorthead sculpin, variation of one spine occurred, in cognatus and ricei, two spines. This character may be useful i f the extent of i t s variation is 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 in a small patch behind the pectoral fin 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 in sculpin taxonomy. This newccharacter is not applicable to field identification, since i t is not visible in uncleared fish. It can, however, be applied in deter- mining the relationships of fish. The following illustration shows the shapes of prickles in 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 cognatus gulosus hubbsi bairdi bairdi base Figure 3« Shapes and proportions of cottine prickles drawn from cleared specimens. 71 Variability does occur in the shape of the prickles within a species. The typical shape is found in the centre of the prickle patchj i t may vary at the perimeter. The shape of prickle is described under individ- ual species. The odd vanes beside the spine in gulosus are peculiar, making the spine appear feather-like. It was found that some species possessed two pores on the tip of the chin (see illustrations of ventral surface of head of different species), while others possessed only one. Robins (1954) noted this character previously. Dr.- R.M.Bailey (pers.comm.) states that in some species the fusion or lack of fusion of pores is subject to marked variation. The following table shows that the amount of variation i n this character in B.C. species is small and that i t is 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 ONE PORE TWO PORES asper 400 5 aleuticus 135 2 princeps 6 0 bairdi shasta 10 0 gpbio 4 0 ricei 21 0 bairdi punctulatus 1 7 bairdi semiscaber 0 3: shorthead sculpin 0 9 hubbsi 0 35 cognatus 1 462 rhotheus 0 33 72 Another previously unreported character found in 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 first basal of the dorsal, in other species only one. Table 23, on the following page presents the variability found in this character in different species. Determination wasmmade on cleared specimens from British Golumbia. The exact function of differences in the number rof spines on the first dorsal basal is 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 fin. The chief function of the fin would seem to be behavioral, however, not locomotory. Even in uncleared fish the number of spines on-the first basal can be determined with fair accuracy. When two are- present the bases of the spines are in contact and form a MV"j when only one is present the bases of the first and next spine are separated by the width of at least one spine. In some species, such as cognatus and ricei, a high degree of variation in the number of spines on the first basal occured, amounting to 10% in 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 in keys. Is i t i s not the simplest character to describe or determine perhaps i t should only be used in det- ermining 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 asper 3 82 aleuticus 0 48 princeps 6 0 cognatus 46 5 shorthead sculpin :;5 0 rhotheus 22 2 hubbsi 39. 1 ricei 12 2 carolinae 7 0 bairdi bairdi 4 . 1 hypselurus 5 0 When the number of spines on the first basal is away from the norm the number of spines is usually abnormally high or too low. Hence two spines on the basal where there are usually one may result from crowd- ing. 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 in the past for different- iation of forms. Increasingly i t has been shown that their high var- iability in 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 is known that serial characters should be used in identifica- tion and naming. Most of the meristic characters in Figure 7 show significant 74 differences in means. Although this establishes that the species in- volved are different, i t doesn't- necessarily enable one to differentiate them. However, reference to the graph will show that some characters do not overlap. That meristic characters in some cases are useful in sep- aration of species should not be obscured. Also the overlap that occurs in the extremities of the ranges may occur so infrequently that the character may be used for separation with a fair degree of certainty. The utility of characters shown on Figure 7 can be obtained directly so that no discussion of these characters will be given. Branchiostegals The usual number of branchiostegals in Cottus i s six. Occasionally seven are found. The frequencies with which sevens occur in different species varies but not sufficiently to be diagnostic. Basals The number of basals in the anal fin equals the number of rays, but the number of basals under the dorsal fin 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 NUMBER OF BASALS 23 24 25 26 27 28 29 30 31 asper 2 20 43 17 1 aleuticus 9 21 8 pririceps 1 3 2 cognatus 1 6 21 22 1 1 shorthead sculpin 1 1 2- rhotheus 17 7 1 hubbsi 4 26 10 ricei 1 6 2 2 carolinae c. 1 3 1 bairdi b. 2 Caudal rays The number of giajjor caudal rays (attached to the two hypural plates) is so constant in the genus that, like the number of branchio- stegals, i t is of no specific taxonomic importance. The minor rays (not attached to hypural plates, above and below the major rays) vary greatly, in fact more than any^other count. In most cases the variation i s so great that they aire unuseable. 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 will be noted that the dorsal minor caudal counts are usually higher than the ventral. 76 TABLE 25 , VARIATION IN MINOR CAUDAL RAYS VENTRAL MINOR CAUDALS SPECIES DORSAL MINOR CAUDALS 6 7 8 9 10 11 4 5 6 7 8 9 1 2 3 19 19 3 8 6 1 2 1 1 1 5 6 16 11 2 3 2 3 7 6 1 5 11 1 2 1 2 1 1 3 3 J 2 I." 2 1 10 11 12 13 14 8 1 1 asper 1 4 32 10 aleuticus 1 5 8 4 bairdi shasta 3 2 cognatus 5 13 14 9 2 shorthead sculpin 1 2 2 hubbsi 3 8 5 1 rhotheus 4 8 4 1 ricei 1 5 carolinae c. 1 1 3 hypselurus 3 2 bairdi b. 4 Lateral line Lateral line pores are a highly useful character. Their numbers may be seen under the description of each species. The length of the lateral line is 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 is more easily determined is a better character. One disadvantage of the lateral line as a taxonomic character is that i t i s not usually complete until a size of about 60mm. (total length) has been attained. As mentioned in the descriptions, exceptions in the completeness of the lateral line, i.e., incomplete when normally complete, do occur. Reproduction Time of reproduction does not lend itself to identification of speci- mens in hand, but i t does to the finding ofethe relationships of species. '77 Two types of spawners would appear to exist in British Columbia. Table 26 gives spawning time of B.C. sculpins. It is known that Cottus asper, aleuticus, hubbsi, and rhotheus spawn in the spring. The eggs in these species are large just before they spawn. Limited observations would indicate that they are not large in the winter. This, and the presence of large (1.0-17) eggs in Cottus cognatus from August to November (no specimens collected later), seems to indicate they are f a l l spawners. Whether cognatus spawns in the f a l l or not, the earlier development of eggs (when none are present in others) indicates a definite physiological difference from asper, aleuticus, hubbsi and rhotheus. Specimens of Cottus ricei from Lake Michigan collected on 11 June possessing eggs 0.8 mm. in diameter might indicate summer or f a l l spawning. These dif- ferences are of taxonomic importance. If changes in spawning time exist, deep-seated behavioral and physiological differences in 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 in 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 in 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 will be pointed out. It will be noted in Table Zd that Cottus asper and Cottus aleuticus have been recorded as occurring in brackish water in 2% of the collections. Doubtless they occur fairly 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 in Salinas Paver, California. Gilbert (1895) found C.aleuticus in brackish water in Alaska and was able to keep one for several days in a saltwater aquarium. The only other instance of a British Columbia species of Cottus being in saline-water is given by Dunbar and Hidebrand .(1952). They found the C.cognatus in brackish water in Ungave Bay, northern Quebec. This, the only instance I know of in 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 in lakes, streams and brackish water. The difference was found to be significant, p<0.02. The difference is chiefly attributable to the more common occurrence of asper in lakes. Another test was run of the "width of streams in which asper and cognatus were collected. This dif- ference was found to be significant, p< 0.05. 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 in B.C. species and that these may be statistically significant. •tyie prickly sculpin seems to be ecologically distinct from other B.C. species by its more common occurrence in lakes than streams, and its more common occurrence on sandy bottoms. The Aleutian sculpin is distinguished by i t s high degree of preference for narrow, swift, clear streams. Frequent occurrence on gravel or mud bottoms, in 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 its name indicates, an inhabitant of strong currents. It has been recorded in three lakes; but two of these, the Upper and Lower Arrow Lakes, possess a definite current. The third collection was made within the influence of an entering stream. A l l col- lections have therefore been made in some current. Differences in food also occur. Northcote (1954) discusses differences in food of asper and rhotheus. The larger size of mouth in rhotheus per- mits i t to utilize 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 in asper and rhotheus and ab- sent in 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 in parenthes SPECIES HABITAT DEPTH STREAM WIDTH •Cottus Streams 68$ aleuticus Lakes 30$ Brackish 2$ • (41) Cottus asper Cottus hubbsi Lakes • 55$ Streams 43$ Brackish 2$ (140) Cottus Streams 69$ cognatus Lakes . 31$ . (54) Cottus Streams 100$ n. sp. (3) Streams 60$ Lakes 40$ (10) Cottus r Streams 84$ rhotheus Streams 1 ft. or less usually, up to 4 f t . (10) Streams usually 1-5 ft.; lakes 1-10 ft. (23) Streams 1-3 ft. up to 5 ft.; lakes 5-6 f t . (23) Cottus Streams 100? (2) Streams 1-3 f t . , usual., range g-5 ft. (5) Streams 1-3 f t . , rarely 1-5 ft. (6) Streams 1-3 f t . (1) 11-20 ft. 50$ 6-20 ft. 25$ + 50 ft. 25$ (12) + 50 ft. 21-50 ft. 11-20 ft. 6-10 ft. I- 5 ft. (16) II- 20 ft. 6-10 f t . 21-50 f t . + 50 f t . (22) 31$ 25$ 25$ 13$ 55$ 18$ 18$ 9$ +50 f t . 50$ I- 5 f t . 50$ (2) 21-50 ft. 50$ + 50 f t . 25$ II- 20 ft. 25$ (4) + 50 f t . 50$ 21-50 f t . 38$ 11-20 f t . 12$ (8) + 50 ft. 100$ (2) as and percentages refer to the number of collections. CURRENT Swift 75$ Mod. 13$ Slow 12$ (8) Swift 50$ Slow 43$ Mod. 7$ (14) Swift 45$ Slow 27$ Mod. 18$ S t i l l 9$ (22) Swift 100$ (2) WATER COLOR Clear 72$ Glacial 14$ Cloudy 14$ (7) Clear 47$ Cloudy 43$ Muddy 13$ Glacial 7$ (15) Clear 58$ Cloudy 26$ Muddy 16$ (19) TEMP- ERATURE Cold Warm Cool PREDATORS Game fish and Dolly Varden American Merganser, lake and Dolly Varden char, cutthroat;and\ .1 brown trout, squawfish, ling and sculpins. CO o Lake char, pike and ling. Cool Swift 43$ Clear 80$ Cool Slow 43$ Glacial 20$ Mod. 14$ (5) (7) Swift 38$ Clear 50$ Cool Mod. 38$ Glacial 33$ Slow 24$ Cloudy 17$ (16) Mod. 100$ (1) Muddy 100$ (1) TABLE 26 continued SPECIES . .BOTTOM Cottus Boulder 36$ aleuticus Gravel 36$ Rocks 18$ Sand 10$ (11) Cottus Sand 35$ Detritus 9$ asper Gravel 26$ Silt 4$ Mud 13$ Boulder 4$ Rock 9$ (54) Cottus Gravel 32$ Boulders 6$ cognatus Mud 25$ Clay 6$ Rocks 17$ Silt 2$ Sand 10$ Detritus 2$ (48) Cottus Rocks 66$ Boulder 34$ n. sp. . (3) Cottus Gravel 40$ Boulder 20$ hubbsi Rocks 17$ Sand 10$ (10) Mud 10$ Cottus Gravel 45$ Rocks 12$ rhotheus' Boulders 19$ Sand 12$ Cottus ' Mud 100$ ricei (l) REPRODUCTION F 0 0 D Spawn from Feb. to mid-June in creeks under boulders. Eggs orange, 1.5-2.0 run. Spawn from mid-Feb. to June Fry - plankton and aquatic insect larvae; in streams under boulders. Adults - insect larvae, fish, C r u s t a c e a , Yellow or orange eggs. Down- molluscs, stream spawning migrations - in coastal streams Ovaries are ripe from August Aquatic insect larvae to at least November. Eggs 1.5 to about 2 mm. Probably spawn from April to June. Probably spawn from April to June Ripe Individual on 11 June from Lake Michigan. Fry - plankton, midge larvae; Adults - insect larvae and fish. Part of habitat data from Carl and Clemens (1953). "Food data in 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 is provided below. 1 (12) Upper preopercular spine not long and shaped like buffalo horn and head not greatly flattened as in Figure 4« 2 (5) 3 (4) Figure 4 One pore on midline of tip of chin (see Figure 5); caudal vertebrae 24-28; 2 spines on the first dorsal basal; dorsal spines usually 8-10; 26-31 basals under the dorsal fins; commonly enter brackish water; lateral line always past second dorsal in specimens over 60 mm. total length. / Figure 5 - Figure 6 Posterior nostrils not tubular (Figure 6); anal rays 15-19; palatine teeth present; black spot present on the posterior portion of the first dorsal and then orange border along dorso- posterior edge; 2-3 spines on preopercle (skin must be removed); prickles usually present on back and sides, occasionally reduced to patch in axil; 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 first dorsal fin; wide orange band present on first dorsal of only spawning male; one spine at corner of preopercle; prickles in axil only or absent, skin slippery; pectoral rays usually 13-15 (occasionally 16) Aleutian sculpin - Cottus aleuticus One pore on either side of midline of tip of chin (see Figure 4)j 20-24 caudal vertebrae; usually one spine on first dorsal basal; dorsal spines usually 7-9; dorsal basals usually 23-26 (occasion- ally to 28); never enter brackish water in 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 comp- lete in specimens whose total length is 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 in contact with the vomerine patch of teeth; dark median band absent in first dorsal. torrent sculpin - Cottus rhotheus Prickles reduced to a weak patch behind pectoral fin (rarely ex- tending onto sides and back past area covered by pectoral fin; usually three, sometimes two, mottled crossbars across back under 84 second dorsalj chin evenly speckled; lateral line not complete except sometimes in 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 pre- sent, not in contact with the vomer; dark marks in first 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 - Cottus hubbsi 10 (9) One to two preopercular spines; lateral line does not extend past second dorsal; 8-9 spines in first dorsal fin; 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 - Cottus n.sp_. 11 (8) Palatine teeth absent; anal rays 9-12 (occasionally 13); ventrals with 3-4 rays; lateral line not extending past second dorsal fin. 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 tip of chin. spoonhead sculpin - Cottus ricei 86 .Co i l l r lu i i i ! 1:1 L 1--. : ! - : " 1 i l . i ; ' i l l I t "I r j ; n ; i':'r. If:: i : l ; - 1-11 TTiT i n - i l l : "if:! i ". i i : : 1;!' Ti-i —: ' t — — :frr Or i 't. 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H u ) b s rr.: fFr 5? ; -• rh i ' t f i BUS — ---' r ii.- I: 1 il-'i »2i ; - l . " i " /3 14. IS 16 / 7 IS "ni Hit irii :• 7 - i l ' i 11: i lirl 1-' :lf| lv\ iz—: I t ; ; •H-- - V i i f l ' i : i ri 5 ei Sir . . : : ; r.r. - ! ; • I.:- ••• i - i.n; Hi? i ' : ; i =rfi Ill : . . . . i agi ( f l t m - IS 1-1 • l : - : •Hi : r l i l -iiii / IT Of Rt 5 HI" u h f .in,'. 351 l i i i T.-:T i i i : :H|I N o t hei 18- _ i l •511 i H l :=I " ; : • 1. _j — — . ' ! 1 -r ;; T rr. r /3 14 /6 1 ' ' 1 17 181 ^ l ° u t Cllf i i - l i l i i r -.-•: ; : i - '<•• •:1 -:r • ^i : ! ' -j i a ipe ITli .rill S I ; •-!- l - r ! , 1 : -1 i : ••-.-y • j . . . • - r i cei l i S •rnT irrl m 1*1; 1: : - 1 -|!;. • i l l . : "< ITS 69 iii; : i : : -.rt; 115 j x h i i s i - \ — EE T : • :!• • . : l • . Q t i s ; ; i •li-i. I-::. nil: 1": " M V£l RI RAE •••I •iiH u b t « r ; 1:1 - ~ . \ . i •.|:. . . : : ! ' ! rlVA the 20 jg [ : : - : : 2/ ^ 1 ' i 1 ' - I , I- - : " ' * l : : h fih l i l l : ; ; ; 22 23 24; 25 • I- 26 ,27' i ' 28 llil. i IS m sLi y f rip "I »- c 0+7 U mean -7 ; standard f- i-̂ |.er-i;or- tiop s j ...j—m {Hi : : i ! h i ; i-irr K i l - I • : '• 1 :|;'' ' I. • | ige, r ' Figure 7 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 in 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 will 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 first two of these subgenera are not now considered as valid since palatine teeth may very within species- and probably occur in 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 sub- genera. 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 ricei. Some western species studied in 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 in two. Group I includes Pacific forms, group II holarctic species, the eastern American forms of which break into Ila (sexually dimorphic) and lib (non sexually dimorphic species), and lastly 89 group III in which are placed ricei and perhaps related palearctic forms. It is likely that examination of Soviet species will 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 will be established in the following discus- sions. CHARACTERISTICS OF SPECIES GROUPS Caudal Vertebrae The number of caudal vertebrae is the principal character on which the three species groups are based. Caudal vertebrae were first 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 in 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 in 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 in 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 line. The amount of overlap occur- ring in other species than ricei (both other groups extend to 24) is small, 24 being an unusual count in these species. Other evidence for the exist- ance of three groups will be dealt with under the headings of the characters that separate them. Dorsal .Spines Table 28 gives the ranges of the dorsal spines in 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 in groups I and II. In most species, as may be seen from the graphs in Figure 7, the midpoint of the range would be a fair indication of the mean. A chi square test on the differences in distribution of midpoints above and below 8.75 in the two groups yield a chi square value having a probability of less than .01. 91 TABLE 2-7 RANGE OF CAUDAL VERTEBRAE SPECIES NUMBER OF CAUDAL VERTEBRAE 20 21 22 23 24 25 26 27 28 29 Group I asper — ~ aleuticus princeps amblvstomopsis czerski — kesserli pretusus Group II rhotheus gulosus hubbsi gobio — kneri poeciolopus tubulatus • beldingi n.sp. bairdi bairdi hypselurus carolinae _c. _ cognatus klamathensis bendirei : Group III ricei 92 Differences in 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 verte- brae and the number of dorsal spines within each group. The significantly higher tendancy in group I to have more dorsal spines is then dissociated from their having a higher vertebral count. The higher number of dorsal spines in group I then confirms the existence of two groups. Table 28 gives dorsal spine counts in the two groups. TABLE 28 DORSAL SPINE RANGE IN GROUPS I AND II SPECIES ~ NUMBER OF DORSAL SPINES 5 6 7 8 9 10 11 Group I 1 asper aleuticus princeps amblystomopsis czerski — kesserli protusus Group II rhotheus : t gulosus hubbsi go bio " kneri poecilopus — tubulatus beldingi bai rdi bairdi — n . s D . — 'hypselurus carolinae c. : cognatus — • klamathensis bendirei 93 Dorsal Rays Table 29 gives the ranges of dorsal rays in group I and group II. It may be seen that the ranges are usually higher in group I than group II. A chi square test shows that the difference is significant (p <.0l). Chi square tests also show that no relationship exists between the number of rays and vertebrae in 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 difficult on this basis. It must be remembered than in many species, particularly where the range is small, large series of specimens have not been examined. Therefore, one expects that, in the future, ranges may be extended, which may increase the degree of overlap. TABLE 29 RANGES OF DORSAL RAYS IN GROUP I AND II SPECIES NUMBER OF DORSAL RAYS 14 15 16 17 I S 19 20 21 22 23 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 — 94 Anal Rays Table 30 gives the ranges of the number of anal rays in groups I and II. Group II was found to have significantly more of the midpoints of its ranges above those of group II (p= -.01). TABLE 30 RANGES OF ANAL RAYS IN SPECIES GROUP I AND II SPECIES NUMBER OF ANAL RAYS 9 10 11 12 13 14 15 16 17 18 19 20 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 Ventral Rays There seems to be a higher frequency of forms having 3 ventral rays in group II than in 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 fin rays of the two groups showed they vrere not statistically different in this respect. Lateral Line Only one out of seven species in 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 in group I I exists to have incomplete lateral lines. Symphysial pores A l l three of the species examined in group I (asper. aleuticus and princeps) normally possess one pore on the tip of the chin. According to Robins and according to my own data, seven out of eight species II possess two pores on the tip 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 in the last two species the one pore has been secondarily derived by fusion. Cottus ricei, 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 in both groups. Their ready gain or loss is presumably the result of converg- ent and divergent evolution. 96 Distribution A l l species of group I are found in Pacific drainages except kesserli which is found in Lake Baikal, U.S.S.R. of Nearctic and Palearctic. Species of group II are holarctic in distribution. The homogeneity of dis- tribution of group I would confirm the common origin of its members. There are indications that group I is more tolerant of saline water than is group II. Cottus asper and aleuticus of group I are known to enter salt water and the presence of several others of this group in maritime islands would also suggest this. Of group II, cognatus (Dunbar and Hildebrand 1952) and poecilopus (Splastenenko 1955) have evidenced ability 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 ricei would, at present, differentiate i t from I and II (see key). Further information on its anatomy and that of other freshwater cottids may indicate its derivation which is not clear'. Robins' groupings have not been deeply examined; they have been adopted as subgroups of II to which they belong without critical examination since specimens of most eastern species were not available for study. The relationships of the different species groups are indicated in the following key. The species in each group are listed following each group, the probable members are in parentheses. 97 KEY TO SPECIES GROUPS IN COTTUS 1 (4) Upper preopercular spine not longer than eye and not buffalo-horn- like; 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, (asperimus) 3 (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, peecil- opus, tubulatus, beldingi, bairdi, hypselurus, carolinae, cognatus, klamathensis, bendirei, n.s£., baileyj girardi. a (b) Sexual dimorphism in breeding features; breeding male charac- terized 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 fi 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 in b r e e d i n g features lacking; males and females similarly colored, anal papilla a small rounded protuberance in both sexes. Fins never black, the spotting restricted to the surfaces o f the rays. Chin characteristi- cally mottled. Red border on fi r s t dorsal f i n reduced or absent. Group lib Cottus girardi, C a r o l i n a ^ (rhotheus). (l) Upper preopercular spine longer than diameter of eye; buffalo- like head greatly flattened; caudal vertebrae 23-25; lateral line complete; bones of head cavernous; one chin pore. Do not occur on Pacific slope Group III - Cottus ricei (sibiricus, spinulosus). 99 CONCLUSIONS 1. Differences were found in 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 in or near brackish water near the coast were found to be significantly different than those just inland, in 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 in Casper between dorsal rays and verte- brae and between anal rays and vertebrae. Pectoral rays and dorsal spines showed no significant correlation with vertebrae. 5. Differences in variability of dorsal spines, dorsal rays, anal and pectoral rays and vertebrae were shown to exist in Casper. 6. Body proportion and meristic differences were found in river systems and at different latitudes in Cottus cognatus. 7. No significant sex differences in dorsal spines, dorsal rays, anal rays, pectoral rays and vertebrae were found in Ccognatus. 8. C.philonips was found to be synonomous with C.cognatus. 9. No sex differences in dorsal spines, dorsal rays, anal rays, pectoral rays and vertebrae were found in Crhotheus. 10". Significant differences exist between B.C. and Washington in pectoral rays of Chubbsi. IGO 11. Significant differences exist in pectoral rays of coastal and non- coastal C.aleuticus. 12. A latitudinal cline in vertebrae, increasing northwards, occurs in C.aleuticus. 13. Clines were shown to exist • from southeast to northwestern North America in anal and pectoral rays in C.ricei. 14. Differences were shown to exist between B.C. species in coloration, body proportion, meristics, distribution and ecology. 15. The taxonomic characters used to classify Cottus were evaluated. 16. Three natural groups were found in 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. 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