Gobio baliki, Turan & Kaya & Bayçelebi & Aksu & Bektaş, 2017

Turan, Davut, Kaya, Cüneyt, Bayçelebi, Esra, Aksu, İsmail & Bektaş, Yusuf, 2017, Gobio baliki, a new gudgeon from Turkey (Teleostei: Cyprinidae), Zootaxa 4350 (2) : -

Gobio baliki , new species

( Fig. 1 )

Holotype: FFR 0 5966, 92 mm SL, male; Turkey: Düzce prov.: stream Asar at Kaynaşlı , 40°46'52"N 31º16'37"E, C. Kaya & İ. Aksu, 0 6 October 2016.

Paratypes: FFR 0 5962, 21, 48–90 mm SL; same data as holotype.— FFR 0 5961, 14, 62–93 mm SL; Turkey: Düzce prov.: stream Aksu at Gölyaka , 40º45'50"N 30º57'46"E, C. Kaya & İ. Aksu, 0 6 October 2016 .— FFR 0 5967, 5, 66–82 mm SL; Turkey: Düzce prov.: stream Asar at Yenitaşköprü , 40º50'08"N 31º06'35"E, C. Kaya, İ. Aksu & Y. Bektaş 14 July 2016 .

Diagnosis. Gobio baliki is distinguished from all other Gobio species in the Marmara and Turkish Black Sea basin by having a greater distance between the anus and the anal-fin origin (7–10% SL vs. 4–7) and the depth of anal-fin being approximately equal to the length of pelvic-fin (vs. depth of anal-fin greater than length of pelvic-fin in all other species). Gobio baliki is further distinguished from G. sakaryaensis by having 5–6 scales between the posterior extremity of the pelvic-fin base and the anus (vs. 6–8), a more slender body (body depth at dorsal-fin origin 18–22% SL vs. 22–27), the midlateral blotches separated from each other (vs. blotches not separated, especially in individuals larger than 70 mm SL) and the snout with a pointed tip (vs. tip blunt). Gobio baliki is also distinguished from G. kizilirmakensis by having less scales between the posterior extremity of the pelvic-fin base and the anus (5–6 vs. 8–10), a greater distance between the pectoral-fin origin and the anal-fin origin (47–52% SL vs. 43–47), the postorbital distance being 1.0–1.2 times in snout length (vs. 1.3–1.6) and scales on the belly being greater than the pupil (vs. smaller). Gobio baliki has 6–8 blotches on the back and upper part of flank (vs. 10–15 in G. kizilirmakensis ) and a pointed snout (vs. blunt). Gobio baliki further differs from G. kovatschevi by having a greater distance between the pectoral-fin origin and the anal-fin origin (47–52% SL vs. 43–47), a more slender snout (snout depth at nostrils 8–10% SL vs. 10–11), a longer postorbital distance (1.0–1.2 times snout length vs. 0.9–1.0), and no black, irregular shaped spots on the top of the head in most individuals (vs. presence in most individuals). Gobio baliki is further distinguished from G. artvinicus by having a greater distance between the pectoral-fin origin and the anal-fin origin (47–52% SL vs. 44–48) and more mid-lateral blotches (8–9, vs. 7–8). In G. baliki , the breast is completely covered by scales and scales are extending slightly behind the isthmus (vs. scales extending forward to half-distance between pectoral fin and isthmus). Gobio baliki is further distinguished from G. bulgaricus by having a shorter head (24–28% SL, vs. 28–30), a greater distance between the pectoral-fin origin and the anal-fin origin (47–52% SL, vs. 44–47), the interorbital distance being 1.5–1.9 times in the eye diameter (vs. 1.1–1.3) and having more mid-lateral blocks blotches (8–9 vs. 6–8).

Description. General appearance is shown in Fig. 1 ; morphometric data are given in Table 2. Body slender, slightly compressed. Predorsal profile convex, postdorsal profile slightly concave and ventral profile straight or slightly convex. Head short, dorsal profile straight at interorbital area, slightly convex in front of nostril, slightly concave at nostril. Snout with pointed tip, its length equal to or smaller than the postorbital distance. Mouth inferior, horseshoe-shaped. Length of mouth gape smaller than its width. Barbels short, reaching to vertical of mid point of pupil. Interorbital width 8–9% SL, 1.4–2.1 times eye diameter. Anus situated approximately at middle between posterior extremity of pelvic fin base and anal-fin origin ( Fig. 2 ). Largest individual observed 94 mm SL.

Lateral line with 40 (6), 41 (12) or 42 (15) scales. 6 (26) or 7 (7) scales rows between lateral line and dorsal-fin origin. 4 (6) or 5 (27) scales between lateral line and anal-fin origin. 5 (21) or 6 (12) scales between posterior extremity of pelvic fin base and anus. 5 (10) or 6 (23) scales between anus and anal-fin origin. Breast completely scaled, scales extending slightly behind isthmus ( Fig. 2 ). Gill rakers 1–3+2–3=3–6 on outer side of first gill arch. Pharyngeal teeth 5.3–3.5, slightly hooked. Dorsal fin with 3 simple and 7½ branched rays, its height approximately equal to pectoral-fin length, distal margin straight or slightly concave. Pectoral fin long, almost reaching 1 to 2 scales in front of pelvic-fin origin in males, 3 or 4 scales in females, distal margin straight or slightly concave. Pectoral fin with 15–17 branched rays. Pelvic fin long, reaching beyond anus in both sexes, distal margin rounded, with 6–7 branched rays. Anal-fin slender, its depth approximately equal to pelvic-fin length, with 3 simple and 6½ branched rays, distal margin straight or slightly concave posteriorly. Caudal fin long, forked, its lobes slightly rounded.

holotype holotype & paratype

mean min max SD

Standard length (mm) 92 70 92

In percent of standard length

Sexual dimorphism. Pectoral fin longer in males than in females.

Colouration. Formalin preserved individuals: Back and flank dark grey, whitish on belly, 8–9 midlateral black blotches, usually well separated from each other. On predorsal back, 6–8 black blotches. Pigment cells denser on upper and lower extremities of exposed part of flank scales and few rows of dark grey pigment cell on free margin of flank scales, forming a dark grey net on flank. Pectoral fin yellowish, with 2-3 rows of black spots; pelvic and anal fins yellowish, without or with few small black spots; dorsal and caudal fins greyish, with 3–4 rows of black spot.

Distribution and notes on biology. Known only from the Büyük Melen ( Fig. 3 ) which flows to the Black Sea at Caferiye, 13 km west of Akçakoca. It inhabits swift flowing water, with cobbled and pebbled bottoms. Etymology. The species is named for Süleyman Balık (İzmir) for his contribution to the knowledge of the ichthyofaunal of Turkey. A noun in genitive, indeclinable.

Figures

FIGURE 1. Gobio baliki, a, holotype, FFR 0 5966, 92 mm SL; b, paratype, FFR 0 5962, 90 mm SL; c, paratype, FFR 0 5962, 86 mm SL; Turkey; stream Büyük Melen.

FIGURE 2. Gobio baliki, a, holotype, FFR 0 5966, 92 mm SL; b, paratype, FFR 0 5961, 86 mm SL; Turkey; stream Büyük Melen.

FIGURE 3. Distribution of Gobio species in Turkey: G. artvinicus (▲), G. baliki (ο), G. battalgilae (▼), G. bulgaricus (□), G. gymnostethus (■), G. hettitorum (), G. insuyanus (♦), G. intermedius (x), G. kızılırmakensis (), G. kovatschevi (), G. maeandricus (), G. microlepidotus (●) and G. sakaryaensis ().