Cottus schitsuumsh, Lemoine, Michael, Young, Michael K., Mckelvey, Kevin S., Eby, Lisa, Pilgrim, Kristine L. & Schwartz, Michael K., 2014

Lemoine, Michael, Young, Michael K., Mckelvey, Kevin S., Eby, Lisa, Pilgrim, Kristine L. & Schwartz, Michael K., 2014, Cottus schitsuumsh, a new species of sculpin (Scorpaeniformes: Cottidae) in the Columbia River basin, Idaho-Montana, USA, Zootaxa 3755 (3), pp. 241-258 : 244-255

Cottus schitsuumsh , new species

Cedar Sculpin

Holotype. UW 151670, male, 91 mm SL, haplotype group 1 ( JX311895 ), East Fork Steamboat Creek, a tributary of the Coeur d’Alene River at West Fork Road ( USFS Road 409) (47.71821°N, 116.20010°W), Shoshone County, Idaho, 29 September 2011.

Paratypes. UW 151671, 2 males and 1 female, 57–73 mm SL, haplotype group 1 ( JX311896 ), CIDA 101,703, 2 males and 1 female, 72–99 mm SL, collected with the holotype.

Additional materials (nontypes, examined morphologically and genetically). Idaho, Shoshone County: (5, 66– 81 mm SL, haplotype group 2, JX311919 ) Bird Creek (47.27235°N, 115.60885°W), 29 September 2011; (5, 68–80 SL, haplotype group 1, JX311898 ) Leiberg Creek (47.72100°N, 116.38335°W), 6 September 2011; (5, 64– 88 mm SL, haplotype group 2, JX311921 ) Red Ives Creek (47.06016°N, 115.33448°W), 29 September 2011; (5, 69– 96 mm SL, haplotype group 1, JX311902 ) West Fork Steamboat Creek (47.71718°N, 116.20380°W), 7 September 2011. Tissue samples (and extracted DNA) are archived at the Wildlife Genetics Laboratory, Rocky Mountain Research Station, Missoula, MT.

Additional materials (nontypes, examined morphologically). Idaho, Benewah County: (2, 50– 70 mm SL, CIDA 68425) Renfro Creek (47.16278°N, 116.40462°W), 11 July 1996. Idaho, Shoshone County: (5, 69– 84 mm SL) Beaver Creek (47.08260°N, 115.35738°W), 29 September 2011; (1, 62 mm SL, CIDA 69113) Buckskin Creek (47.99148°N, 116.22247°W), 24 July 1997; (2, 71– 86 mm SL, CIDA 68475) Eagle Creek (47.64813°N, 115.91920°W), 23 August 1996; (5, 71– 83 mm SL) East Fork Steamboat (47.71821°N, 116.20010°W), 29 September 2011; (5, 72– 79 mm SL) Leiberg Creek (47.72100°N, 116.38335°W), 6 September 2011; (10, 44– 95 mm SL) Steamboat Creek (47.69685°N, 116.167867°W), 18 October 2011; (4, 70– 97 mm SL) West Fork Steamboat Creek (47.71718°N, 116.2038°W), 18 October 2011; (1, 73 mm SL, UW 152969) West Fork Steamboat Creek (47.71718°N, 116.2038°W), 7 September 2011. Montana, Mineral County: (5, 48– 62 mm SL) Fish Creek (46.951°N, 114.67359°W), 12 October 2011; (5, 50– 76 mm SL) Fish Creek (46.96693°N, 114.65292°W), 12 October 2011; (5, 45– 67 mm SL) St. Regis River (47.43131°N, 115.74357°W), 15 October 2011; (5, 48– 86 mm SL) Trout Creek (47.09768°N, 114.90475°W), 12 October 2011; (5, 51– 67 mm SL) Trout Creek (47.13611°N, 114.85036°W), 12 October 2011; (5, 51– 91 mm SL) Trout Creek (47.14311°N, 114.83298°W), 12 October 2011; (6, 49– 83 mm SL) Twomile Creek (47.295958°N, 115.171311°W), 12 October 2011. Montana, Sanders County: (8, 53– 77 mm SL) Prospect Creek (47.57452°N, 115.39381°W), 15 October 2011.

Additional materials (nontypes, examined genetically). Haplotype group 1. Idaho, Kootenai County: (2, JX282597 ) 4th of July Creek (47.58208°N, 116.46721°W); (2, JX311897 ) Hayden Creek (47.82378°N, 116.65348°W). Idaho, Shoshone County: (2, JX311893 ) Bumblebee Creek (47.63522°N, 116.27645°W); (2, JX311899 ) Moon Creek (47.55719°N, 116.03062°W); (2, JX311900 ) Rampike Creek (47.81965°N, 115.96189°W); (2, JX311901 ) West Fork Eagle Creek (47.67772°N, 115.88087°W). Montana, Mineral County: (2, JX311903 ) Big Creek (47.37580°N, 115.39283°W). (1, JX311904 ) Burdette Creek (46.81331°N, 114.62097°W). (1, JX311905 ) Burdette Creek (46.83436°N, 114.60488°W). (2, JX311907 ) East Fork Packer Creek (47.43260°N, 115.49248°W). (2, JX311908 ) Savenac Creek (47.39438°N, 115.39210°W). (1, JX311909 ) Savenac Creek (47.43467°N, 115.39532°W). (1, JX311910 ) Savenac Creek (47.46251°N, 115.38812°W). (2, JX311911 ) St. Regis River (47.41834°N, 115.62450°W). (1, JX311912 ) St. Regis River (47.43131°N, 115.74357°W). (1, JX311913 ) St. Regis River (47.43675°N, 115.68220°W). (2, JX311914 ) Straight Creek (46.91092°N, 114.81761°W). (2, JX311915 ) Twelvemile Creek (47.37603°N, 115.25982°W). (1, JX311915 ) Twelvemile Creek (47.42681°N, 115.24120°W). Montana, Sanders County: (2, JX311917 ) Wilkes Creek (47.55313°N, 115.42111°W). Haplotype group 2. Idaho, Shoshone County: (2, JX282598 ) Beaver Creek (47.08314°N, 115.35790°W). (2, JX311918 ) Bird Creek (47.27229°N 115.60893°W). (2, JX311920 ) North Fork St. Joe River (47.35768°N, 115.73658°W). (2, JX311922 ) Simmons Creek (47.13888°N, 115.39229°W). (2, JX311923 ) St. Joe River (47.04652°N, 115.18094°W). Haplotype group 3. Idaho, Shoshone County: (2, JX282599 ) Bechtel Creek (46.99509°N, 116.28479°W). Tissue samples (and extracted DNA) are archived at the Wildlife Genetics Laboratory, Rocky Mountain Research Station, Missoula, MT. See Young et al. (2013; table S1) for additional materials used in this analysis.

Morphological diagnosis. Cottus schitsuumsh is diagnosed from all other Cottus in the upper Columbia River basin by the lack of a second preopercular spine, palatine tooth patches smaller and separate from the vomerine tooth patch, and axillary prickling.

Cottus schitsuumsh is distinguished from C. cognatus , C. confusus , C. hubbsi , and C. rhotheus by the lack of a second preopercular spine. Cottus schitsuumsh is distinguished from C. cf. bairdii and C. beldingii by the presence of axillary prickling. In addition, C. schitsuumsh has palatine tooth patches smaller than the vomerine tooth patch and the patches are separated. Cottus cf. bairdii has palatine tooth patches equal to or larger in size than the vomerine tooth patch. Cottus beldingii generally lacks palatine teeth.

Molecular diagnosis. Haplotypes of C. schitsuumsh differed from those of all other members of the genus Cottus (represented in GenBank or in this study) at three positions ( Table 1 ). Additionally, they differed from all other North American Cottus haplotypes at an additional position. Nucleotides at two other positions were diagnostic for individual haplotypes.

1Based on C. reinii mitome (GenBank accession AP004442 ; Miya et al. 2003).

2Relative to all Cottus haplotypes in GenBank (n = 104 from 283 accessions) and from Cottus collected throughout the upper Columbia and Missouri River basins ( Young et al. 2013) and in this study (n = 44).

Description. Cottus schitsuumsh is a moderately sized species of Cottus rarely exceeding 90 mm SL with anal fin rays 14 (rarely 13 or 15), the final posterior anal-fin ray commonly branched; dorsal-fin spines 8 (rarely 7 or 9); dorsal-fin rays 17–20 (usually 18–19) with the posterior dorsal-fin ray branched; pectoral-fin rays 13–14 (usually 14); and pelvic-fin rays 4 (rarely 3) and of similar length. There are 2 medial-chin pores, 10–12 preoperculomandibular pores, and 2 postmaxillary pores (rarely 0). Dorsal fins are generally not connected but occasionally have a slight connection at the base. Prickling is consistent and restricted to a trapezoidal area, widest in the axillary region and narrowest along the lateral line under the beginning of the second dorsal fin. Palatine teeth are present in two or fewer rows and sometimes on only one side. The palatine tooth patches are smaller than and separated from the vomerine tooth patch and generally equal if present on both sides. The lateral line is incomplete, ending below the latter half of the second dorsal fin. One preopercular spine was observed among all specimens. Preopercular spines are greatly reduced and skin-covered. The mouth width/head width fraction ranges from ½ to 2/3.

Morphometrics of the holotype (91 mm SL, male) and 3 paratypes (57–73 mm SL, 2 males and 1 female) as a percentage of SL (mean and range): caudal peduncle depth (8.8, 8.1–10.6); caudal peduncle length (13.9, 12.3– 17.4); head length (19.7, 16.8–23.4); head width (26.8, 21.6–34.3); lateral line length (59.5, 51.3–70.6); snout length (9.0, 6.5–17.4); mouth width (14.2, 12.9–15.9); interpelvic width (3.5, 2.3–4.6); longest pectoral ray (24.3, 21.2–33.7), longest pelvic ray (18.5, 15.1–24.4).

Mottling of C. schitsuumsh is variable and consists of at least two forms. One has black-brown mottling on a brown-olive background mainly above the lateral line that stops under the soft dorsal fin ( Fig. 4 ), and weak saddling is occasionally present (Fig. 5). The pectoral fins have faint black-brown contours running vertically. The other form lacks mottling or spotting over the body and the background color can be light brown, rust orange, or yellow. Both types have a dark blotchy marking near the base of the caudal rays and the first dorsal fin is generally dorsally darkened. Both forms are sympatric in the upper Spokane River basin, Idaho, but the mottled form has only been observed in Montana.

Comparisons. Cottus schitsuumsh tended to have more anal fin rays (mode, 14 rays) than the other species (modes, 12 or 13 rays) among our samples ( Table 2 ) and relative to other sculpins in this region ( Wydoski and Whitney 2003). Pelvic ray counts are similar among the observed Cottus species, but C. cognatus commonly had a greatly reduced fourth pelvic-fin ray (cf. Wydoski & Whitney 2003). Cottus rhotheus has more pectoral rays than C. schitsuumsh . Counts of medial-chin pores did not differ among species, although C. schitsuumsh tended to have more preoperculomandibular pores than other species and more postmaxillary pores than C. cf. bairdii , C. beldingii , and C. cognatus ( Table 3 ). Cottus schitsuumsh can be further distinguished from C. cognatus and C. beldingii by the presence of palatine teeth ( Table 4 ). The palatine tooth patch of C. schitsuumsh consists of two or fewer rows, may occur on only one side, and is about ½ the size of the vomerine tooth patch. The palatine tooth patch is similar to or larger than the vomerine tooth patch in C. rhotheus , C. hubbsi , and C. cf. bairdii . Cottus schitsuumsh also differs from C. hubbsi and C. rhotheus by having an incomplete lateral line.

Originally confused with C. confusus ( Bailey & Bond 1963) , C. schitsuumsh can be distinguished from it by having only one preopercular spine that is small (length less than half the eye diameter) and skin-covered ( Fig. 6 ). Most specimens of C. schitsuumsh also lack lateral-line pores on the caudal peduncle ( Fig. 7 ). Pores along the lateral line of C. confusus , usually end beneath the latter half of the second dorsal fin and reappear at the end of the caudal peduncle near the origin of the caudal rays.

1Fourth ray in the pelvic fin of C. cognatus reduced (ca. ½ of other rays; cf. Wydoski & Whitney 2003).

Most morphometric features separated C. schitsuumsh from one or more of the Cottus species. Caudalpeduncle depth, head length, mouth width, and interpelvic width statistically differed more often between C. schitsuumsh and the other species than did other measures ( Table 5 ). Frequency distributions of these features emphasized these differences ( Tables 6 , 7 ). With respect to C. confusus , C. schitsuumsh differed by having a shorter lateral line, wider mouth, longer snout, and narrower interpelvic width.

Standardized head length Distribution and ecology. Cottus schitsuumsh is distributed in all streams sampled in the upper Coeur d’Alene and St. Joe River drainages of the Spokane River basin above Post Falls near Post Falls, Idaho, and sporadically in the middle Clark Fork River basin between Fish Creek and Prospect Creek, approximately between Tarkio and Thompson Falls, Montana ( Fig. 1 ). This species is common to abundant in cool to cold tributaries with cobble and gravel bottoms. Cottus schitsuumsh is sympatric with Westslope Cutthroat Trout, Oncorhynchus clarkii lewisi , and Bull Trout, Salvelinus confluentus , throughout its distribution, with C. rhotheus in Idaho, and with C. cognatus in Montana. No effort was undertaken to find this species in Lake Coeur d’Alene or in the river main stems, but haplotype differences between fish from the Coeur d’Alene and St. Joe River basins imply that lineages in these basins are isolated and diverging.

The distribution in Idaho is consistent with that of other terrestrial and aquatic fauna e.g., Idaho Giant Salamander, Plethodon idahoensis , that persisted immediately south of the extent of Cordilleran glaciation in the Northern Rocky Mountain Refugium ( Carstens et al. 2005; Shafer et al. 2010). The disjunct distribution in the Clark Fork River basin in western Montana is puzzling (although known for some time; Hendricks 1997). There are no known peri- or post-glacial hydrological connections between these basins because all mountain divides are more than 150 m above the glacial Lake Missoula highstand ( Smith 2006). Because sculpins were a common and legal baitfish in Montana until this century, it is plausible that populations in western Montana resulted from human-assisted translocation. Regardless of their means of arrival, the Montana populations have haplotypes similar to those in the Coeur d’Alene River basin and probably originated from that watershed.

Etymology. The word schitsu’umsh (pronounced s-CHEET-sue-umsh) is Americanist phonetic notation of the spoken word used by the first peoples who inhabited portions of northern Idaho and western Montana, now recognized as the Coeur d’Alene Tribe. In modern usage it means “those who were found here” and refers to the people of this tribe. The current distribution of C. schitsuumsh overlaps with most of the historical homeland of this tribe. The common name refers to a common riparian tree in this area, Western Redcedar, Thuja plicata .

Remarks. Although originally assigned to C. confusus , a broad-scale genetic biodiversity inventory of fishes in the northern Rocky Mountains ( Young et al. 2013) indicated, based on sequence differences among two mtDNA regions, that C. schitsuumsh was not closely related to that species. In the present study, the more geographically comprehensive sample of fishes subjected to genetic analysis coupled with the morphological assessment confirmed that interpretation. In a broader context, however, these findings support previous assertions that the taxonomy of sculpins in North America is far from resolved ( Neely 2003; Kinziger et al. 2005; April et al. 2011). Paraphyly and polyphyly among a number of taxa are evident in phylogenetic trees based on COI ( Fig. 2 ). Although partly attributable to a lack of resolution resulting from the limited number of nucleotides in this region ( Pollock et al. 2002), the results are similar to those observed for other mtDNA regions that included additional taxa and more nucleotides ( Kinziger et al. 2005; Young et al. 2013). In addition, the large genetic differences between clades within other species of Cottus in the western U.S., such as C. beldingii and C. confusus , suggest that additional taxa remain to be described (also see April et al. 2011).

The ambiguous morphological distinctions among sculpin species ( Jenkins & Burkhead 1994; McPhail 2007) argue for the use of genetic information for species discovery and delineation ( Baldwin & Weigt 2012). Moreover, some of the variation in diagnostic traits within species ascribed to geography may instead reflect the existence of cryptic taxa ( Bickford et al. 2007). As has been suggested for other groups of species, an integrative taxonomy relying on morphology and genes will be necessary to understand the details of the systematic relations and boundaries of individual taxa among members of the genus Cottus .

Comparative material for morphological and genetic analyses (GenBank accession numbers for COI haplotypes). Cottus beldingii : (4, 45– 54 mm SL, JX311884 ) North Fork Asotin Creek, Asotin County, WA (46.25856°N, 117.29962°W), 9 August 2011. Cottus cognatus : (5, 65– 81 mm SL, JX311885 ) Marten Creek, Sanders County, MT (47.89233°N 115.82088°W), 20 September 2011; (5, 44– 74 mm SL, JX311886 , JX311887 ) Skalkaho Creek, Ravalli County, MT (46.18128°N, 114.07984°W), 8 January 2012. Cottus cf. bairdii (Rocky Mountain Sculpin): (5, 60– 91 mm SL, JX311882 ) Elk Creek, Missoula County, MT (46.92707°N, 113.43934°W), 23 August 2011. Cottus confusus : (5, 77– 89 mm SL, JX311888 ) Little North Fork Clearwater River, Shoshone County, ID (47.06579°N, 115.85287°W), 19 September 2011; (2, 74– 89 mm SL, pending) Pole Creek, Blaine County, ID (43.90974°N, 114.76370°W), 7 November 2012; (2, 59– 68 mm SL, pending) Salmon River, Blaine County, ID (43.88382°N, 114.76370°W), 7 November 2012; (2, 67– 90 mm SL, pending) Smiley Creek, Blaine County, ID (43.89650°N, 114.79853°W), 7 November 2012. Cottus hubbsi : (1, 112 mm SL, JX311892 ) Dragoon Creek, Spokane County, WA (47.88619°N 117.38400°W), 16 August 2011. Cottus rhotheus : (1, 71 mm SL, JX311890 ) Dragoon Creek, Spokane County, WA (47.88619°N 117.38400°W), 16 August 2011; (5, 59– 84 mm SL, JX311891 ) Spokane River, Spokane County, WA (47.66060°N, 117.43559°W), 12 September 2011.

Comparative material for morphological analyses. Cottus beldingii : (2, 56– 57 mm SL, CIDA 68169) Big Bear Creek, Latah County, ID (46.63927°N, 116.65417°W), 1 July 1995; (4, 57– 68 mm SL, CIDA 68443) Clear Creek, Clearwater County, ID (46.04655°N, 115.79120°W) 18 July 1996; (2, 57– 58 mm SL, CIDA 68110) East Fork Potlatch River, Clearwater County, ID (46.82873°N, 116.38967°W), 25 July 1969; (2, 52– 60 mm SL, CIDA 68369) Glade Creek, Idaho County, ID (46.22338°N, 115.52972°W), 18 July 1996; (2, 51– 58 mm SL, CIDA 68309) Lochsa River, Idaho County, ID (46.46113°N, 115.04775°W), 15 August 1969; (4, 39– 64 mm SL, CIDA 68192) Middle Fork Clearwater River, Idaho County, ID (46.14052°N, 115.69819°W), 23July 1969; (1, 46 mm SL) North Fork Asotin Creek, Asotin County, WA (44.25856°N, 117.29962°W), 9 August 2011; (4, 49– 63 mm SL, CIDA 68389) North Fork Clearwater River, Clearwater County, ID (46.81125°N, 115.20330°W), 20 August 1969; (4, 40– 64 mm SL, CIDA 81824) South Fork Clearwater River, Idaho County, ID (46.03107°N, 115.97420°W), 20 August 2003; (2, 48– 55 mm SL) Swauk Creek, Kittatas County, WA (47.17556°N, 120.72944°W), 9 June 1996; (6, 42– 75 mm SL) Tucannon River, Columbia County, WA (46.21694°N, 117.71111°W), 1 August 1993; (2, 35– 68 mm SL, CIDA 69562) Weitas Creek, Clearwater County, ID (46.53143°N, 115.42108°W), 4 August 1998. Cottus cf. bairdii (Rocky Mountain Sculpin): (5, 84– 99 mm SL) Elk Creek, Missoula County, MT (46.92707°N, 113.43934°W), 23 August 2011. Cottus cognatus : (10, 32– 81 mm SL) Blodgett Creek, Ravalli County, MT (46.28756°N, 114.16837°W), 3 August 2012; (2, 51– 54 mm SL, CIDA 70563) Burton Creek, Boundary County, ID (48.772227°N, 116.46445°W), 26 July 2001; (2, 31– 40 mm SL, CIDA 69961) Kalispell Creek, Bonner County, ID (48.57615°N, 116.95607°W), 18 July 2000; (10, 59– 88 mm SL) Overwhich Creek, Ravalli County, MT (45.66498°N, 114.28005°W), 21 August 2012; (3, 50– 56 mm SL, CIDA 68609) Pack River, Bonner County, ID (48.47588°N, 116.55390°W), 12 October 1972; (5, 48– 71 mm SL) Petty Creek, Mineral County, MT (46.91728°N, 114.45675°W), 12 October 2011; (5, 52– 82 mm SL) Petty Creek, Mineral County, MT (46.99196°N, 114.44762°W), 12 October 2011; (5, 48– 76 mm SL) Petty Creek, Mineral County, MT (46.93116°N, 114.44568°W), 12 October 2011; (2, 48– 53 mm SL) Skalkaho Creek, Ravalli County, MT (46.18128°N, 114.07984°W), 8 January 2012; (10, 66- 77 mm SL) Sleeping Child Creek, Ravalli County, MT (46.11015°N, 114.00677°W), 10 August 2012; (3, 32– 81 mm SL) Sullivan Creek, Pend Oreille County, WA (48.86333°N, 117.30500°W), 20 August 1996; (6, 42– 71 mm SL) Tonata Creek, Ferry County, WA (48.83308°N, 118.80858°W), 1 September 1996. Cottus confusus : (3, 69– 77 mm SL) Alpine Creek, Blaine County, ID (43.89740°N, 114.91070°W), 15 August 2011; (1, 47 mm SL) American River, Yakima County, WA (46.92611°N, 121.36389°W), 1 September 1993; (3, 35– 70 mm SL) Entiat River, Chelan County, WA (47.92528°N, 120.51167°W), 1 October 1996; (2, 31– 56 mm SL) Frenchman Creek, Blaine County, ID (43.87108°N, 114.77263°W), 1 August 1998; (3, 54– 64 mm SL) Lost River, Okanogan County, WA (48.65556°N, 120.50444°W), 31 August 1999; (3, 52– 77 mm SL, CIDA 69441) Pole Creek, Blaine County, ID (43.91063°N, 114.74935°W), 26 August 1998; (3, 47– 70 mm SL, CIDA 69831) Salmon River, Blaine County, ID (43.83368°N, 114.75885°W), 26 July 1990; (5, 32– 60 mm SL, CIDA 70993) Salmon River, Blaine County, ID (43.85745°N, 114.75448°W), 3 August 2003; (3, 54– 74 mm SL) Salmon River, Blaine County, ID (43.88382°N, 114.76370°W), 7 November 2012; (7, 33– 78 mm SL, CIDA 69443) Smiley Creek, Blaine County, ID (43.82638°N, 114.82743°W), 26 July 1998; (3, 33– 78 mm SL) Smiley Creek, Blaine County, ID (43.89650°N, 114.79853°W), 7 November 2012; (2, 50 mm SL, CIDA 69503) Vat Creek, Blaine County, ID (43.97637°N, 114.84807°W), 8 August 1998. Cottus hubbsi : (4, 57– 68 mm SL) Chewuch River, Okanogan County, WA (48.56472°N, 120.17667°W), 31 August 1999; (2, 44– 53 mm SL, CIDA 68934) Siegel Creek, Idaho County, ID (45.78730°N, 115.36688°W), 11 July 1997; (5, 35– 73 mm SL) Similkameen River, Okanogan County, WA (48.95667°N, 119.64583°W), 21 July 1998; (3, 53– 63 mm SL, CIDA 69699) Skull Creek, Clearwater County, ID (46.87165°N, 115.38710°W), 9 September 1999; (3, 67– 103 mm SL, CIDA 68494) Selway River, Idaho County, ID (45.73492°N, 114.75885°W), 12 July 1970; (1, 68 mm SL) West Fork Sanpoil River, Okanogan County, WA (48.51417°N, 118.88889°W), 23 August 1999. Cottus rhotheus : (5, 67– 79 mm SL) Ramskull Creek, Benewah County, ID (47.08918°N, 116.63813°W), 11 August 2011; (5, 63– 94 mm SL) Spokane River, Spokane County, WA (47.66060°N, 117.43559°W), 12 September 2011; (10, 41– 90 mm SL, JX311891 ) Spokane River, Spokane County, WA (47.69878°N, 117.04451°W), 12 September 2011.

Comparative material for genetic analyses from GenBank. Cottus aleuticus : (5) EU523991 , EU523992 , HQ010070 , JN024987 , JN024988 . Cottus asper : (2) EU523994 , JQ354065 . Cottus aturi : (1) EF416966 . Cottus bairdii : (20) EF416967 , EU522459 , EU523998 , EU524490 , EU524496 , EU524506 , HQ557187 , HQ557189 , JN024992 , JN024996 , JN024997 , JN024999 , JN025004 , JN025006 , JN025010 , JN025011 , JN025012 , JN025013 , JN025022 , JN025023 . Cottus beldingii : (5) HQ557196 , HQ579024 , JN025027 , JN025029 , JN025034 . Cottus caeruleomentum : (2) JN025040 , JN025041 . Cottus carolinae : (8) JN025046 , JN025047 , JN025051 , JN025052 , JN025053 , JN025058 , JN025060 , JN025064 . Cottus cf. bairdii : JN025069 , JN025070 , JN025071 . Cottus cf. carolinae : (2) JN025072 , JN025073 . Cottus chattahoochee : (1) JN025077 . Cottus cognatus : (7) EU523999 , EU524511 , EU524517 , JN025085 , JN025090 , JN025091 , JN025099 . Cottus duranii : (1) EF416968 . Cottus girardi : (1) HQ557143 . Cottus gobio : (6) EF416970 , EF416971 , EF416973 , HQ960512 , HQ960869 , HQ960870 . Cottus gulosus : (2) JN025102 , JN025103 . Cottus hispaniolensis : (1) EF416977 . Cottus hubbsi : (1) JN025104 . Cottus hypselurus : (3) JN025105 , JN025106 , JN025110 . Cottus klamathensis : (1) JN025112 . Cottus leiopomus : (1) HQ971431 . Cottus perifretum : (1) EF416978 . Cottus perplexus : (3) EF416984 , JN025117 , JN025120 . Cottus pitensis : (1) JN025122 . Cottus poecilopus : (5) HQ536339 , HQ960874 , HQ960878 , HQ961093 , JN025128 . Cottus reinii : (1) AP004442 . Cottus rhenanus : (3) EF416985 , EF416986 , EF416988 . Cottus rhotheus : (3) EU524000 , HQ579026 , JN025131 . Cottus ricei : (4) EU522462 , EU524521 , HQ557327 , JN025134 . Cottus sibiricus : (1) EF416990 . Cottus tallapoosae : (6) JN025137 , JN025140 , JN025143 , JN025144 , JN025145 , JN025146 . Cottus tenuis : (2) HQ579025 , JN025147 . Leptocottus armatus : (1) FJ164712 .

Comparative material for genetic analyses from regional sampling (with GenBank accession numbers, if available). Cottus beldingii : (5, JX282576 – JX282580 , 2 pending) Feather Creek, Clearwater County, ID (46.91599°N, 116.40383°W), Potlatch River, Clearwater County, ID (46.91376°N, 116.39121°W); Goddard Creek, Idaho County, ID (46.10088°N, 115.55723°W); Musselshell Creek, Clearwater County, ID (46.35239°N, 115.75575°W); Lolo Creek, Clearwater County, ID (46.40720°N, 115.67415°W); Portneuf River, Bannock County, ID (42.70837°N, 112.21222°W); Pass Creek, Custer County, ID (43.93533°N, 113.44703°W). Cottus cf. bairdii : (5, JX282572 – JX282575 , JX311883 , 2 pending) Alice Creek, Lewis and Clark County, MT (47.10702°N, 112.4767°W); Colts Creek, Flathead County, MT (48.99259°N, 114.49092°W); Trout Creek, Lewis and Clark County, MT (46.90852°N, 112.38711°W); Taylor Fork Gallatin River, Gallatin County, MT (45.04594°N, 111.37768°W); Highwood Creek, Choteau County, MT (47.47503°N, 110.61261°W); Thayer Creek, Beaverhead County, MT (45.20349°N, 113.29354°W); Mussigbrod Creek, Beaverhead County, MT (45.76858°N, 113.58538°W). Cottus cognatus : (8, JX282581 – JX282588 ) Beaver Creek, Missoula County, MT (47.38776°N, 113.66057°W); Little Thompson River, Sanders County, MT (47.69347°N, 114.81318°W); Lake Creek, Lincoln County, MT (48.03698°N, 115.49420°W); Kraft Creek, Missoula County, MT (47.45570°N, 113.75697°W); Twelvemile, Mineral County, MT (47.37603°N, 115.25982°W); Lower Twin Creek, Flathead County, MT (47.99185°N, 113.56328°W); Overwhich Creek, Ravalli County, MT (45.66399°N, 114.15168°W). Cottus confusus : (7, JX282589 – JX282594 , JX311889 , 9 pending) Crooked Fork Creek, Clearwater County, ID (46.66158°N, 114.67718°W); Fishing Creek, Clearwater County, ID (46.51996°N, 114.86661°W); Cayuse Creek, Clearwater County, ID (46.59984°N, 114.89314°W); French Creek, Clearwater County, ID (46.52659°N, 115.65508°W); South Fork Red River, Idaho County, ID (45.67204°N, 115.36070°W); Newsome Creek, Idaho County, ID (45.91054°N, 115.62920°W); Baldy Creek, Idaho County, ID (45.91278°N, 115.64021°W); Fallert Springs, Butte County, ID (43.91625°N, 112.12339°W); Wildhorse Creek, Custer County, ID (43.85320°N, 114.08758°W); Pass Creek, Clark County, ID (44.13444°N, 112.99285°W); Big Gulch, Custer County, ID (44.34647°N, 113.52006°W); Eighteenmile Creek, Lemhi County, ID (44.53546°N, 113.24102°W); Loon Creek, Custer County, ID (44.80694°N, 114.81070°W); Salmon River, Blaine County, ID (43.88382°N, 114.76370°W); Pole Creek, Blaine County, ID (43.90974°N, 114.75629°W); Smiley Creek, Blaine County, ID (43.89650°N, 114.79853°W). Cottus hubbsi : (1, pending) South Fork Rock Creek, Power County, ID (42.50190°N, 112.82991°W). Cottus rhotheus : (2, JX282595 – JX282596 ) East Fork Emerald Creek, Latah County, ID (47.02486°N, 116.32903°W); Little Sand Creek, Latah County, ID (46.92103°N, 116.62829°W).

Figures

FIGURE 1. Distribution of specimens of Cottus schitsuumsh (filled circles; type location, unfilled star) examined within the upper Spokane River (the Couer d’Alene and St. Joe rivers) in Idaho and the Clark Fork River in Montana. Locations of specimens of other Cottus species examined from adjacent basins are depicted (unfilled squares); others beyond this area are noted in the text. Inset: Columbia River basin in the United States.

FIGURE 2. Outgroup-rooted neighbor-joining tree of Cottus from all available haplotypes based on uncorrected p - distances for cytochrome c subunit 1 sequences. State and province abbreviations are given for North American samples, and river basins are noted for C. beldingii, C. confusus, and C. schitsuumsh in Idaho and Montana. Cottus poecilopus, C. reinii, those in the Cottopsis clade (Kinziger et al. 2005), and the outgroup Leptocottus armatus are not shown.

FIGURE 4. Illustration of the holotype of Cottus schitsuumsh.

FIGURE 6. Preopercular bone of Cottus schitsuumsh (left) and of Cottus confusus (right).

FIGURE 7. Lateral pores absent on the caudal peduncle on Cottus schitsuumsh (left) and present on Cottus confusus (right).

Tables

TABLE 1. Diagnostic characters for Cottus schitsuumsh in the mtDNA cytochrome c oxidase subunit 1 (COI) region.

Position1	Nucleotide	Diagnostic for2
5577	T	C. schitsuumsh haplotype 3
5664	G	C. schitsuumsh in North America
5685	T	C. schitsuumsh haplotype 2
5868	T	C. schitsuumsh
6081	T	C. schitsuumsh
6120	T	C. schitsuumsh

TABLE 2. Range (mode) for counts of Cottus fin spines and rays examined in this study. Samples sizes are noted after each sampling location or species.

Species	Dorsal spines	Dorsal rays	Anal rays	Pelvic rays	Pectoral rays
Spokane River basin (n = 64)	7–9 (8)	17–19 (18)	13–15 (14)	3–4 (4)	12–14 (14)
Clark Fork River basin (n = 44)	7–9 (8)	17–19 (18)	12–14 (14)	3–4 (4)	12–15 (14)
C. beldingii (n = 39)	7–8 (7)	16–18 (17)	11–13 (12)	3–4 (4)	13–15 (14)
C. cf. bairdii (n = 10)	6–8 (8)	16–19 (17)	12–14 (13)	4	13–15 (14)
C. cognatus (n = 73)	7–9 (8)	15–19 (18)	10–13 (12)	3–4 (4)1	12–14 (13)
C. confusus (n = 49)	7–9 (8)	15–19 (17)	10–14 (13)	4	11–15 (13)
C. hubbsi (n = 19)	7–8 (8)	15–18 (17)	12–14 (13)	4	13–16 (15)
C. rhotheus (n = 26)	7–9 (8)	15–18 (16)	11–14 (12)	4	15–17 (16)

TABLE 3. Range (mode) of pore counts for Cottus examined in this study.

Species Medial chin pores	Preoperculomandibular pores	Postmaxillary	pores
Spokane River basin (n = 64) (2)	10–12 (12)	0–2 (2)
Clark Fork River basin (n = 44) (2)	10–12 (12)	0–2 (2)
C. beldingii (n = 39) (2)	10–12 (11)	(2)
C. cf. bairdii (n = 10) (2)	10–11 (11)	0–2 (1)1
C. cognatus (n = 73) (2)	10–12 (10)	0–1 (0)
C. confusus (n = 49) (2)	10–12 (11)	1–2 (2)
C. hubbsi (n = 19) (2)	10–12 (11)	1–2 (2)
C. rhotheus (n = 26) (2)	10–12 (11)	1–2 (2)
1Postmaxillary pores for C. cf. bairdii were consistently in a	lower position compared to that of other	species.

TABLE 4. Additional meristic and morphological characters of Cottus examined in this study.

Species	Preopercular spines	Prickling	Palatine teeth	Lateral line pores on caudal peduncle
Spokane River basin (n = 64)	1	Consistent and restricted to a trapezoidal area, widest in the axillary region and narrowest along the lateral line	1–2 rows on 1–2 sides	No (59), yes (5)
Clark Fork River basin (n = 44)	1	Consistent and restricted to a trapezoidal area, widest in the axillary region and narrowest along the lateral line	1–2 rows on 1–2 sides	No (40), yes (4)
C. beldingii (n = 39)	1–2 (1)	Absent	Absent	No
C. cf. bairdii (n = 10)	1–2 (2)	Generally absent; some prickles (1–7) can be present axial to the pectoral fin	≥ 2 rows on both sides	No
C. cognatus (n = 73)	2–3 (2)	Generally absent; occasionally small patches in the axillary region	Absent	No
C. confusus (n = 49)	2–3 (2)	Consistent and restricted to a trapezoidal area, widest in the axillary region and narrowest along the lateral line	1–2 rows on 1–2 sides	No (3), yes (46)
C. hubbsi (n = 19)	3	Large patch under pectoral fins, scattered elsewhere	≥ 2 rows on both sides	Yes
C. rhotheus (n = 26)	3–4 (3)	Covers most of the body	≥ 2 rows on both sides	Yes

TABLE 5. Mean values for 11 morphometric characteristics among Cottus examined in this study. Morphometric values were standardized by dividing by standard length, except mouth width was standardized by head width. An asterisk denotes a significant pairwise difference (ANCOVA, Scheffé test; P <0.05) between the pooled sample of C. schitsuumsh and another species.

Species	Caudal peduncle depth	Caudal peduncle length	Head length	Head width	Lateral line length	Snout length
Spokane River basin (n = 64)	0.086	0.144	0.191	0.264	0.582	0.086
Clark Fork River basin (n = 44)	0.088	0.144	0.187	0.265	0.584	0.086
C. beldingii (n = 39)	0.097*	0.134*	0.211*	0.273	0.620*	0.092
C. cf. bairdii (n = 10)	0.077*	0.131	0.208*	0.301*	0.599	0.084
C. cognatus (n = 73)	0.078*	0.165*	0.221*	0.257	0.565	0.076*
C. confusus (n = 49)	0.084	0.157	0.202	0.265	0.667*	0.078*
C. hubbsi (n = 19)	0.081*	0.131	0.245*	0.299*	0.711*	0.095
C. rhotheus (n = 26)	0.062*	0.134	0.213*	0.304*	0.678*	0.109*
continued.

TABLE 6. Frequency distribution of head length divided by standard length (%) for Cottus examined in this study.

Species Spokane River basin (n = 64)	Mouth width 0.608	Interpelvic width 0.034	Longest pectoral ray 0.338	Longest pelvic ray 0.180	Longest dorsal ray 0.124
Clark Fork River basin (n = 44)	0.605	0.036	0.337	0.179	0.123
C. beldingii (n = 39)	0.509*	0.042*	0.282*	0.167*	0.116
C. cf. bairdii (n = 10)	0.522*	0.043*	0.325	0.191	0.106
C. cognatus (n = 73)	0.505*	0.044*	0.287*	0.198*	0.110*
C. confusus (n = 49)	0.527*	0.039*	0.314	0.178	0.117
C. hubbsi (n = 19)	0.541*	0.045*	0.302	0.217*	0.126
C. rhotheus (n = 26)	0.599	0.038	0.284*	0.185	0.129

TABLE 7. Frequency distribution of interpelvic width divided by standard length (%) for Cottus examined in this study.

	Standardized interpelvic width
Species	1.5 2.0 2.5 3.0 3.5	4.0	4.5	5.0	5.5	6.0	6.5	7.0
Spokane River basin (n = 64)	2 1 5 18 16	19	2		1
Clark Fork River basin (n = 44)	2 1 10 15	12	2			2
C. beldingii (n = 39)	2 7	12	11	4	1		2
C. cf. bairdii (n = 10)		4	4	2
C. cognatus (n = 73)	1 2 7	19	19	15	7	2		1
C. confusus (n = 49)	5 15	16	11	1	1
C. hubbsi (n = 19)	4	3	6	2	2	1	1
C. rhotheus (n = 26)	4 2 6	8	5	1