Oxynoemacheilus hazarensis, Freyhof, Jörg & Özuluğ, Müfit, 2017

Freyhof, Jörg & Özuluğ, Müfit, 2017, Oxynoemacheilus hazarensis, a new species from Lake Hazar in Turkey, with remarks on O. euphraticus (Teleostei: Nemacheilidae), Zootaxa 4247 (4), pp. 378-390 : 379-384

publication ID	https://doi.org/ 10.11646/zootaxa.4247.4.2
publication LSID	lsid:zoobank.org:pub:C6132ED5-A674-493F-9AFA-2FB03EB88E14
DOI	https://doi.org/10.5281/zenodo.5662537
persistent identifier	https://treatment.plazi.org/id/B51F2F36-D860-FFF0-FF63-FA12FA19E244
treatment provided by	Plazi
scientific name	Oxynoemacheilus hazarensis
status	sp. nov.

Treatment

Oxynoemacheilus hazarensis View in CoL , new species

( Figs. 1–6 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 View FIGURE 6 )

Holotype. IUSHM 2017-1171, 44 mm SL; Turkey: Elazığ prov.: north-eastern shore of Lake Hazar , 38° 28.398N 39° 18.093E. GoogleMaps

Paratypes. IUSHM 2017-1172, 22, 30–46 mm SL; FSJF 2512, 11 , 44–62 mm SL; same data as holotype GoogleMaps .

Diagnosis. Oxynoemacheilus hazarensis is distinguished from the other species of Oxynoemacheilus in the Tigris and Euphrates drainages by a combination of characters, none of them unique. Oxynoemacheilus hazarensis belongs to a group of species ( O. chomanicus , O. frenatus , O. gyndes , O. kaynaki , O. kiabii and O. zagrosensis ) which lack a suborbital groove in males (vs. present in O. bergianus , O. euphraticus , O. hanae , O. longipinnis , O. karunensis , O. kurdistanicus and O. parvinae ) and a slightly emarginate or truncate caudal fin (vs. deeply emarginate or forked in O. argyrogramma , O. bergianus , O. euphraticus , O. hanae , O. longipinnis , O. karunensis , O. kurdistanicus and O. parvinae ).

The new species is superficially similar and occurs adjacent to O. frenatus . Oxynoemacheilus hazarensis is distinguished from O. frenatus by having an incision in the middle of the upper lip (vs. absent or with a shallow groove in the middle of the upper lip), the colour pattern on the flank is not interrupted by an unpigmented zone along the lateral line (vs. interrupted), the caudal fin is slightly emarginate (vs. almost truncate) and O. hazarensis lack scales on the back and flank in front of the anus (vs. scales present).

Oxynoemacheilus hazarensis is distinguished from O. chomanicus and O. zagrosensis by having longer barbels, the maxillary barbel reaching beyond the middle of the eye (vs. to anterior eye margin or middle of eye), having no scales on the back and flank in front of the anus (vs. scales present at least below the dorsal-fin base, on the predorsal back and the flank behind a vertical of the tip of the pectoral fin in most individuals) and having an incomplete lateral line (vs. complete).

It is distinguished from O. kiabii by the presence of a central pore in the supratemporal canal (vs. absence), three pores in the supratemporal canal (vs. 4–6 pores), flank with a mottled colour pattern, with vertically elongated, dark-brown blotches on the caudal peduncle in some individuals (vs. flank with very large, vertically elongated and distinct blotches most distinct on flank behind dorsal-fin base), a shorter head (length 24–26% SL vs. 26–30) and a larger predorsal distance (51–54% SL vs. 48–52).

The new species is distinguished from O. gyndes by the presence of a central pore in the supratemporal canal (vs. absence), the lateral line reaching to a vertical below the dorsal-fin base or above the anal-fin base (vs. to below pectoral-fin), the dorsal-fin usually with 2 brown bands on rays (vs. 5–7) and the caudal-fins with 2–4 brown bands on rays (vs. 6–10).

Two additional species occur in the adjacent upper Euphrates drainage. Oxynoemacheilus hazarensis is distinguished from O. paucilepis by lacking a suborbital groove in males (vs. present) and having an incomplete lateral line (vs. complete), a greater predorsal length (51–54% SL vs. 43–45), a greater preanal length (73–77% SL vs. 68–69) and a longer caudal peduncle (17–21% SL vs. 11–13). Oxynoemacheilus hazarensis is distinguished from O. kaynaki by having an incomplete lateral line (vs. complete), a slightly emarginated caudal fin (vs. truncate), a longer predorsal body (predorsal length 51–54% SL vs. 46–50) and no scales on the back and flank in front of the anus (vs. present).

Description. For general appearance see Figs. 1–5 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 ; morphometric data are provided in Table 1. Medium sized and moderately stout species with a blunt head. Body deepest at dorsal-fin origin or at about midline between nape and dorsal-fin origin, depth decreasing continuously towards caudal-fin base. No hump at nape. Greatest body width at pectoral-fin base. Section of head roundish, flattened on ventral surface. Caudal peduncle compressed laterally, 1.6–1.9 (mean 1.7) times longer than deep. No or a very shallow, usually roundish axillary lobe at base of pelvic fin, fully attached to body. Pelvic-fin origin below second or third branched dorsal-fin ray. Anal-fin origin clearly behind vertical of middle between dorsal- and caudal-fin origins. Pectoral fin reaching approximately 55– 78% of distance from pectoral-fin origin to pelvic-fin origin. Pelvic fin not reaching vertical of tip of last dorsal-fin ray, reaching to a short distance in front of anus. Anus about one eye diameter in front of anal-fin origin. Anal fin not reaching caudal-fin base. A short and shallow dorsal adipose crest on caudal peduncle, a short ventral adipose crest. Margin of dorsal fin straight or slightly convex. Caudal fin slightly emarginate. Largest known specimen 65 mm SL.

Dorsal fin with 7½ (1), 8½ (14) branched rays. Anal fin with 5½ (15) branched rays. Caudal fin with 8+8 (15) branched rays. Pectoral fin with 10 (13), 11 (2) and pelvic fin with 7 (15) rays. Body covered by isolated embedded scales on caudal peduncle, no scales on back and flank in front of anus. Lateral line incomplete, reaching to a vertical below dorsal-fin base or above anal-fin base. Two lateral and one central pore in supratemporal canal. Anterior nostril opening at end of a low, pointed and flap-like tube. Posterior tip of anterior nostril overlapping posterior nostril when folded backwards. No suborbital groove in males. Male with longer pectoral fin. Mouth large, arched ( Fig. 6 View FIGURE 6 ). Lips very thick, with strongly marked furrows. A deep median interruption in lower lip. A median incision in upper lip. Processus dentiformis narrow and pointed. No median notch in lower jaw. Barbels moderately long, inner rostral barbel not reaching to base of maxillary barbel; outer one reaching to vertical of anterior eye margin. Maxillary barbel reaching to or beyond middle of eye.

Coloration. Body yellowish with fine, dark-brown mottled pattern in life and preserved individuals. Head plain brown on top or with mottled pattern, cheeks with fine dark-brown spots or mottled pattern, without colour pattern ventrally in some individuals. Flank below a line from pectoral-fin base to anus with fine dark-brown mottling. Colour pattern on flank not interrupted by lateral line. Back with two, rarely one wide, dark-brown saddles, irregularly shaped and set, usually wider than interspaces, not fused to lateral blotches. A large, roundish or irregularly shaped, dark brown blotch at dorsal fin-origin and below posterior half of dorsal-fin base. Two or three wide, dark-brown saddles on upper caudal peduncle, fused with blotches or bars on flank in few individuals. Flank with 6–12 large, dark-brown, irregularly shaped vertically elongated blotches or bars along lateral midline. Flank below lateral series of blotches with mottled patter. Two black or brown blotches at upper and lower posterior extremity of caudal peduncle, not fused together. Dorsal-fin usually with two wide, brown bands on rays, caudal-fins with 2–4 wide, irregularly shapes, brown bands on rays. Anal-, pelvic- and pectoral fins hyaline, with few dark-brown spots on rays or with almost browns rays.

Distribution. Oxynoemacheilus hazarensis was found in Lake Hazar, a large tectonic lake in eastern Turkey, and one of the sources of the Tigris. It may be endemic to Lake Hazar.

Etymology. The species is named for its type locality, Lake Hazar. An adjective.

Remarks. If this is confirmed by intensive field-work in the region, O. hazarensis would be the third fish species endemic to Lake Hazar after Aphanius asquamatus (Cyprinodontidae) and Alburnus heckeli (Cyprinidae) .