Cottus gratzianowi Sideleva, Naseka & Zhidkov, 2015, sp. nov.
Creators: name: Sideleva, Valentina G.
name: Naseka, Alexander M.
name: Zhidkov, Zakhar V.
Publisher: name: Zenodo
Year: 2015
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Actinopterygii
Scorpaeniformes
Cottidae
Cottus
Cottus gratzianowi

description: Cottus gratzianowi, sp. nov.
(Figs 2, 3, 5, 6)
Holotype. ZIN 55596, 63 mm SL; Ukhtomitsa River village of Korotetskaya (Vologda Province), 60°18′19″N, 38°40′30″E, Onega River drainage, White Sea basin; coll. A. Naseka & Z. Zhidkov, July 2010.
Paratypes. ZIN 55597, 17 specimens, 42–60 mm SL, same data as holotype.
Diagnosis. Cottus gratzianowi sp. nov. is diagnosed from all other described members of the genus Cottus in Europe east of the Meuse (except C. koshewnikowi) in having the following combination of character states: no transverse dark bands on the pelvic fin, a single median chin canal pore, an incomplete lateral line not reaching behind the anal-fin insertion, and the position of the lateral line which is located considerably above the mid-line of the flank. Cottus gratzianowi sp. nov. is distinguished from C. koshewnikowi by a larger eye (horizontal diameter 23−28% HL, equal to or exceeding snout length vs. 16−25% HL, less than snout length), a rounded caudal fin (vs. commonly truncated), frequent presence of one to three branched rays in median part of the pectoral fin (vs. usual absence), an interrupted supratemporal canal commissure with 4 pores (vs. non-interrupted, with 3 pores), the pelvic fin extending to the anus in both sexes (vs. not reaching the anus), a short lateral-line canal extending to below the fifth to tenth ray of the second dorsal fin, with 15−24 pores, with few interruption (vs. commonly extending to below the 9th to 15th ray of the second dorsal fin, with modally 21−27 pores, with few to numerous interruptions), abdominal vertebrae commonly 10 (vs. 11), and contrasting black blotches on all fins including pelvic and anal fins (vs. no blotches on pelvic and anal fins).
Description. Proportional measurements of the holotype and paratypes are given in Table 1. Body humped behind head, deep and compressed; maximum body depth 4.3−5.5 times in SL (5.4 in holotype) and markedly less than HL (Figs 2, 3). Caudal peduncle length 6.8−9 times in SL (6.8 in holotype), caudal peduncle depth 1.7−2.3 times in its length (2.2 in holotype). Prickles (modified scales) numerous, located below and above lateral line; just behind pectoral base, area of prickling extended to back and gradually tapered caudad, terminating below middle of second dorsal fin. Prickle possessing roundish basis and short sharp spine.
Head large, its length, only slightly less than or equal to width, 2.5−3.3 times in SL (3.3 in holotype), depressed (Fig. 2 a −c). Small and very shallow dermal tubercles on dorsal surface of head. Interbranchial space wide, 2.5−3.8 times in HL (2.7 in holotype) (Fig. 2 c). Three preopercular spines; uppermost spine longest, slightly curved upward, its length about 6 times in SL; second spine short, about 3 times in length of uppermost spine; third spine blunt and covered by skin. Snout steep and elongated, its length 3.7−5 times in HL (4.2 in holotype). Anterior nostril forming short cylindrical pigmented tube. Posterior nostril as slender tube, 3 times as small as anterior nostril. Eye relatively large, eye horizontal diameter 3.5−4.4 times in HL (4.2 in holotype), equal or greater than snout length; dorsal margin of orbit elevated. Interorbital space narrow; its width 1.2−2 times in eye horizontal diameter (1.5 in holotype) about 6.5−9.3 times in HL (6.5 in holotype). Mouth horizontal and terminal; upper jaw extending caudad to below anterior margin of pupil. Length of upper jaw 2.8−3.7 times in HL (2.8 in holotype); lower jaw slightly shorter than upper jaw.
Teeth simple, conical, similar in shape and size, grouped in bands on jaws and prevomer; no teeth on palatines. Upper lip thick, lateral lip lobes well developed. Gill slit large (46−58% HL), located completely above pectoralfin base. Outer gill rakers on first gill arch 3 or 4, small and tuberculate, covered with spines at tip. Inner gill rakers on first gill arch 4 or 5, two median gill rakers longer than marginal ones, of trapezoidal shape, laterally compressed and expanded at base, top and sides, armored with tiny sharp spines.
Genital papilla of breeding males triangular, short, not reaching base of first anal ray. Three piloric caecae, one long and two short.
Fin-ray counts are given in Table 2. First dorsal fin originating behind vertical through dorsal tip of opercular flap; length of first dorsal-fin base about 5−6.3 times in SL and about 2.2−3 times in length of second dorsal fin base (2.6 in holotype). No gap between end of terminal membrane of first dorsal fin and second dorsal-fin origin; length of second dorsal-fin base 2.2−2.8 times in SL (2.4 in holotype); first ray of second dorsal-fin about 3 times as short as its longest ray.
First dorsal fin Second dorsal fin Anal fin Pectoral fin
VI VII VIII 15 16 17 18 19 20 12 13 14 13 14 15 C. gratzianowi 2 14* 2 4 13 * 1 12* 6 4* 12 2 (n=18)
C. koshewnikowi 1 19 3 2 9 11 1 8 12 3 4 16 3 (n=23), Volga
C. koshewnikowi 3 2 2 3 4 1 1 3 1 (n=5), Northern
Dvina
C. koshewnikowi 5 6 3 5 2 1 3 8 2 8 1 (n=11), Pechora
Anal fin originating at short distance from anus, below third ray of second dorsal fin; length of anal-fin base about 1.3 times as short as length of second dorsal fin base, and 2.8−3 times in SL (3 in holotype), about equal to head length; length of longest anal-fin ray about equal to length of longest second dorsal-fin ray (equal in holotype). Caudal fin rounded, with 11 or 12 rays supported by hypural plate, 8 middle rays branched and upper 2 and lower 1−2 rays unbranched, and 12−14 (6−7 dorsal and 6−7 ventral) procurrent rays. Pelvic fin extending to anus; two inner soft rays longer than two outer rays; outer ray with long free tip; narrow pelvic base 7 times in length of longest pelvic-fin ray. Pectoral-fin base oblique, broad, its base about 3 times in HL; pectoral-fin length 3−3.4 times in SL (3.4 in holotype); tip of longest ray reaching below base of third or fourth ray of second dorsal fin; one to three medial (longest) rays clearly branched in 56% of examined specimens (in holotype and 9 paratypes) (Fig. 5 a).
Lateral-line system. Cephalic sensory canals developed and interconnected except preoperculo-mandibular sensory canal. Supraorbital canal pores 3 (on each side); infraorbital canal pores 8−9 (usually 8); temporal canal pores 3. Temporal canals of left and right side connected via supratemporal commissure interrupted in middle, with two paired pores instead of one; preoperculo-mandibular canal pores 11 on both sides with five paired pores and single large median pore on chin. Lateral-line canal with 15−24 pores (averaging 19.8) (Table 3), extending along dorsal profile of body, reaching below fifth to tenth ray of second dorsal fin, sometimes (in 2 specimens from 18) interrupted at very end with one or two free canal segments.
Vertebrae. Abdominal vertebrae 10 or 11; caudal vertebrae 22 or 23, total 32−34 (Table 4); long, thin pleural ribs on the parapophyses of commonly three last abdominal vertebrae (Fig. 6).
Predorsal 2 Abdominal Caudal vertebrae Total vertebrae
vertebrae vertebrae
8 9 10 10 11 12 21 22 23 24 32 33 34 35
C. gratzianowi 2 16* 12 6* 6 12* 2 14 2 * (n=18)
C. koshewnikowi 9 12 2 1 22 2 12 9 2 13 8 (n= 23), Volga
C. koshewnikowi 5 5 1 4 1 4 (n=5), Northern
Dvina
C. koshewnikowi 1 10 10 1 2 8 1 2 7 2 (n=11), Pechora
Colouration. Body background light olive; overall body dark mottled, blotches forming marble pattern (Fig. 2). Head dorsally dark, with dark blotches laterally similar to body. Distinct melanophores and their clusters densely located on ventral surface of head and bases of pectoral and pelvic fins. Dark spots forming transverse bands on both dorsal, pectoral and caudal fins. First dorsal-fin margin in adult males light, whitish.
Distribution and habitat. The species is currently known from the Ukhtomitsa River, a tributary of the Modlona River (a Lake Vozhe tributary) in the Onega River drainage, the White See basin (Fig. 8). Cottus gratzianowi sp. nov. occurs in a relatively cool in summer small river with moderate to rapid current, gravel and cobble bottom, and not very dense submerged aquatic vegetation.
Etymology. The new species is named in honour of Valerian Ivanovich Gratzianow [Gratsianov] (1876−1932), the author of the first taxonomic review of Russian fishes "Versuch einer Übersicht der Fische des Russischen Reiches in systematischer und geographischer Hinsicht" (Gratzianow 1907a), who described Cottus koshewnikowi. We retained the original latinised spelling of the surname (Gratzianow).
Comparison. Cottus gratzianowi sp. nov. belongs to C. gobio species group as possessing no transverse dark bands on the pelvic fin, a commonly single median chin canal pore and non-spatulate prickles (see Kottelat & Freyhof 2007). Freshwater sculpins from the White Sea basin have not been distinguished from Volga sculpin and appeared in literature under the name either Cottus gobio (e.g. Novoselov 2008; Novoselov et al. 2013; Parin et al. 2014) or C. koshewnikowi (e.g., Kottelat & Freyhof 2007). Cottus gratzianowi sp. nov. and C. koshewnikowi share an incomplete lateral line not reaching behind the anal-fin insertion and located considerably above the mid-line of the flank.
Cottus gratzianowi sp. nov. form the Onega River drainage is distinguished from C. koshewnikowi from the Volga (type locality) by a set of the following character states. Cottus gratzianowi sp. nov. possesses a larger eye: eye horizontal diameter, 23−28 (mean 25) % HL, is equal to or exceeds snout length, 20−27 (mean 24) % HL (vs. eye diameter less than snout length, 16−23, mean 19, and 22−28, mean 25, respectively) (Table 1), a rounded caudal fin (vs. truncated) (Fig. 3, 4), the pelvic fin extending to the anus in both sexes (vs. not reaching the anus), frequent presence of one to three branched rays in median part of the pectoral fin (56% of specimens vs. 0 to 2%) (Fig. 5), the supratemporal canal commissure often interrupted in the middle and possessing 4 pores (vs. noninterrupted, with 3 pores), a short lateral-line canal extending to below the fifth to tenth ray of the second dorsal fin, with 15−24 pores (vs. extending to below the ninth to fifteenth ray of the second dorsal fin, with 21−27 pores) (Table 3). Only six from 18 (33%) specimens of C. gratzianowi sp. nov. have the lateral-line canal slightly interrupted at its end with one or two free canal segments while C. koshewnikowi commonly (94% of specimens) have the lateral line considerably interrupted with two to nine free segments in its posterior section. Post-pectoral prickling in C. gratzianowi sp. nov. is dense and occupies a wider area than in C. koshewnikowi where prickels are sparse and located only under the pectoral fin. The new species has contrasting black blotches on all fins including the pelvic and anal fins while no blotches on either pelvic or anal fin are developed in C. koshewnikowi. There are also some differences in fin-ray counts between C. gratzianowi sp. nov. and C. koshewnikowi from the type locality (Table 2), the former having lower numbers of second dorsal-fin rays (15−18, averaging 16.8, vs. 16−20, averaging 17.5) and anal-fin rays (12−13, averaging 12.3, vs. 12−14, averaging 12.8). In the new species, total vertebrae are 32−34 similar to C. koshewnikowi from the Volga but in C. gratzianowi sp. nov. the number of abdominal vertebrae is most often 10 (averaging 10.3) vs. commonly 11 in Volga C. koshewnikowi (averaging 11.0) while the number of caudal vertebrae is commonly 23 (averaging 22.7) vs. 21−23, commonly 22 (averaging 22.3). This vertebral feature, a longer caudal region, in combination with a shorter anal fin (commonly 12 rays vs. 13, see Table 2) determines a relatively longer caudal peduncle in the new species as shown above (mean 12.8% SL vs. 8.7% SL, see Table 1). The new species and the Volga C. koshewnikowi are well discriminated by a complex of morphometric characters as can be seen from results of a DFA presented below.
As to sculpins from other rivers of the Arctic basin in Europe, an opinion was expressed that the sculpin from the Pechora River may represent a distinct species, Cottus milvensis Soldatov, 1924, though no distinguishing characters were given (Kottelat & Freyhof 2007). Soldatov (1924) recorded Cottus gobio in the Pechora River, while two juvenile specimens from the Mylva tributary were described by him as a new subspecies C. gobio milvensis (whereabouts of the syntypes are unknown). These two specimens differed from the fish identified as C. gobio gobio by a complete lateral line, longer both dorsal and anal fins, and some departure in the prickling. All specimens we examined (18 in total available at ZIN, see below in the list of material) were tentatively identified by us as C. koshewnikovi. Volga and Pechora specimens share most diagnostic characters (e.g., a smaller eye) mentioned above in the comparison between C. gratzianowi sp. nov. and Volga C. koshewnikovi as can be seen from Tables 1−4. However, the Pechora specimens differ from the Volga specimens in having a slightly longer second dorsal fin, 16−19 rays vs. 17−19, though mode value, 18, is the same (Table 2), a markedly longer caudal peduncle (11−20 % SL)−longer than in C. gratzianowi sp. nov. and, accordingly, a longer caudal vertebral region, 22−24, modally 23. The number of total vertebrae, 33−35, modally 34, is higher in the Pechora specimens than in the Volga sample. This feature needs a further study based on a more numerous material. However, the number of abdominal vertebrae is 11 in the Pechora sample (a character state typical of C. koshewnikovi) in contrast to 10 in C. gratzianowi sp. nov. As to the Northern Dvina, a geographically close drainage in the White Sea basin, only five specimens were available for the examination including three old specimens in poor condition. The morphometric characters, fin-ray, lateral-line, and vertebral counts indicate to their probable conspecificity with the Pechora species we tentatively identify as C. koshewnikovi, but one specimen had branched pectoral-fin rays.
Discriminant Function Analysis (DFA) of morphometric characters was performed for 53 examined specimens (as in Table 1): 9 specimens of C. gratzianowi sp. nov. (holotype and 8 paratypes), 21 specimens including syntypes of C. koshewnikowi (Volga River drainage), 5 specimens of C. koshewnikowi from the Northern Dvina, and 18 specimens from the Pechora.
The DFA using morphometric measurements revealed significant morphological shape differences between the new species and the other samples (Fig. 7, Table 5). This analysis correctly classified all individuals of the new species, C. gratzianowi sp. nov., as well as the Volga sculpin (C. koshewnikowi), and the combined sample of individuals from the Northern Dvina and the Pechora tentatively identified as C. koshewnikowi. Statistics values are as follows: Wilks’ Lambda 0.00121, approx. F (69, 81) =9.9956, p<0.0000, which indicate almost perfect discrimination. Cottus gratzianowi sp. nov. from the Onega River drainage is the most distant from the Volga sculpin (Squared Mahalanobis Distance equal 116.5); the Pechora and the Northern Dvina samples are closer (72.4 and 96.1, respectively) but still significantly distant. The most removed, by the morphometric characters considered, are the Volga and the Northern Dvina samples (224.6) and the Volga and the Pechora (167.4). For all mentioned comparisons, p<0.0000.
Partial Lambdas, demonstrating the unique contribution of the respective variable to the discriminatory power of the whole model, are given in Table 5. The most significant (Partial Lambda <0.7) for discrimination of the samples under consideration are length of caudal peduncle, head depth, snout length, head width, length of gill slit, and horizontal eye diameter.
Thus, the Pechora and the Northern Dvina combined sample is well discriminated by a complex of morphometric characters from both C. koshewnikowi from the Volga and C. gratzianowi sp. nov. A further study of these sculpins is needed.
Comparative material. Cottus koshewnikowi. Caspian Sea basin: Syntypes: ZMMU Р-2001 (4, SL 47–53 mm), Goredva River at village of Ligachevo; ZMMU Р-2658 (20, SL 44–76 mm), same locality; ZMMU P- 2688 (3, SL 46−71 mm), same locality; ZMMU Р-3118 (1, SL 56 mm), same locality. Non-type material: ZMMU Р- 3912 (1, SL 40 mm) Seliger Lake; ZIN 15540 (10, SL 45-84 mm), Kos’va River (left tributary of Kama); ZIN 15777 (4, SL 62−78 mm) Kama River at village of Ust-Divia; ZIN 55581 (60, SL 51–98 mm), Kama River at town of Perm'; ZIN 55582 (11, SL 39–66 mm), Oka River at town of Kaluga; ZIN 55583 (29, SL 48.5–95 mm), Kara River (Kama system); ZIN 55685 (5, SL 45−97 mm), Kolosleyka River, Kama River system.
Baltic Sea basin: ZIN 8568 (5, SL 60.8–72.8 mm) Neva River at St Petersburg; ZIN 1909 (4, SL 54.7–68.0 mm) Neva River; ZIN 3718 (1, SL 34.5–56.5 mm), Neva River; ZIN 14439 (5, SL 57.8–82.0 mm) Neva River, Ostrovki; ZIN 14493 (2, SL 60.8–100.0 mm), same locality; ZIN 23480 (5, SL 19.5–30.5 mm) Neva River downstream of Mga River mouth; ZIN 36171 (3, SL 37.0– 51 mm), Neva River at St Petersburg; ZIN 40739 (2, SL 40.5–41.0 mm), Ladoga Lake; ZIN 41251 (2, SL 61.0–73.0 mm), Neva River at Ostrovky; ZIN 41253 (2, SL 67.5– 69.5 mm), Neva River at St Petersburg; ZIN 51904 (6, SL 41.0– 51.5 mm), Ladoga Lake, 5 кm from Kraskovo, depth 4.5 m; ZIN 52249 (1, SL 78.0 mm), Lute River at Sikovitsy, Pskov Province; ZIN 52861 (2, SL 40.0–52.0 mm), Ladoga Lake; ZIN 54243 (5, SL 66.2–73.0 mm), Neva River delta; ZIN 54247 (1, SL 71.0 mm), Neva River, depth 15–20 m; ZIN 55686 (75, SL 48.0– 57.5 mm), Izhora River at town of Gatchina.
Barentz Sea basin: ZIN 11331 (7, SL 57.2–88.5 mm), Pechora River; ZIN 37102 (2, SL 52.0–58.0 mm), upper Pechora River, 62о N, 58о44’E; ZIN 41252 (1, SL 70 mm), Pechora River; ZIN 50221 (3, SL 77−79 mm), Ydzhyd- Lyaga River, tributary of Ilych, Pechora drainage; ZIN 55687 (6, SL 63−74 mm), Koshym River, tributary of Pechora River.
White Sea basin: ZIN 41256 (1, SL 77.0 mm), Northern Dvina River at town of Arkhangelsk; ZIN 52124 (2, SL 75, 74.6), Yavzora River, tributary of Pinega, Northern Dvina drainage; ZIN 55688 (2, SL 63, 71 mm), Dvinitsa River, Northern Dvina river system.
Cottus gobio. ZIN 13510 (1, SL 58.5 mm), Sillamae; ZIN 41255 (1, SL 62.0 mm), Baltic Sea, Svybiriken Bay, Aland Islands: Gradeso.
Cottus poecilopus. Syntypes: NMW 78816 (1, SL 84.5 mm) Ober-Ungarn, Karpaten; NMW 78816 (2, SL 88, 92 mm) same locality; NMW 6729 (3, SL 82−92 mm); non type: ZIN 315 (1, 90 mm), Vistula River, ZIN 37661 (1, SL 66 mm), Teresva River, Danube drainage, Ukraine.
Cottus metae. NMW (3, SL 75−79 mm), Krupa River, Sava system, Danube.
description: Published as part of Sideleva, Valentina G., Naseka, Alexander M. & Zhidkov, Zakhar V., 2015, A new species of Cottus from the Onega River drainage, White Sea basin (Actinopterygii: Scorpaeniformes: Cottidae), pp. 419-430 in Zootaxa 3949 (3) on pages 420-430, DOI: 10.11646/zootaxa.3949.3.7, http://zenodo.org/record/243672