Oxynoemacheilus kurdistanicus, Kamangar, Barzan Bahrami, Prokofiev, Artem M., Ghaderi, Edris & Nalbant, Theodore T., 2014

Kamangar, Barzan Bahrami, Prokofiev, Artem M., Ghaderi, Edris & Nalbant, Theodore T., 2014, Stone loaches of Choman River system, Kurdistan, Iran (Teleostei: Cypriniformes: Nemacheilidae), Zootaxa 3755 (1), pp. 33-61 : 38-43

Oxynoemacheilus kurdistanicus sp. nov.

( Fig. 3 )

Material: Holotype: FCFUK 146, male, 57.8 mm SL, Choman River (Tajaban, station 6), Baneh, Kurdistan, Iran, 35° 56' 53" N, 45° 41' 40" E, June, 2009, leg. B.B. Kamangar, E. Ghaderi.

Paratypes: FCFUK 147 – FCFUK 170, 12 males, 34.1–55.3 mm SL, 12 females, 32.1–50.9 mm SL, the same data as for the holotype; ZMMU 23084, 2 males, 35.2–50.6 mm SL, 2 females, 46.1–54.7 mm SL, the same data as for the holotype.

Non-type specimens: FCFUK 171 - FCFUK 174, 4 juveniles, 22.4–30.2 mm SL, the same data as for the holotype; ZMMU 23137, 1 juvenile, ca. 30 mm SL, the same data as for the holotype; FCFUK 175, 1 female, 31.3 mm SL, Choman River (Jemli, station 10) Baneh, Kurdistan, Iran, 35° 57' 54" N, 45° 42' 30" E, June 2009, leg. B.B. Kamangar, E. Ghaderi.

Diagnosis: A species of Oxynoemacheilus with usually 9 branched rays in the dorsal fin, very slender and compressed caudal peduncle, complete body lateral line and with transversely banded pattern.

Description: Morphometric and meristic features are explained in Tables 3 and 4. Body ( Figs. 3 a, 3b) elongate, rather thick anteriorly, laterally compressed posteriorly; dorsal contour arched; head slightly higher than wide; trunk as deep as wide to slightly deeper than wide before dorsal-fin origin; caudal peduncle very slender though not elongated (length being commensurable to lateral length of head), elliptical in cross-section at beginning, becoming strongly compressed at the base of caudal fin. Snout shorter than postorbital length, blunt, its dorsal contour sharply declining toward tip in lateral view. Eyes moderate, dorsolateral in position. Dorsal fin originated at about mid-length of body, its distal margin being nearly straight to slightly convex; distal margin of anal fin convex; pelvic fins inserted under anterior third of dorsal-fin base, slightly not reaching anal-fin origin, their pointed tips formed by 2nd branched ray; pectoral fins not reaching a level of dorsal-fin origin, with tips bluntly pointed, formed by 2nd to 3rd branched ray. Caudal fin forked, both lobes of equal size and with bluntly pointed tips. Pelvic axillary lobe absent, but body wall above insertion of pelvics having skin fold lacking free posterior tip. Dorsal and ventral adipose crests very weakly expressed, though sometimes rather long. Anus is close to anal-fin origin.

Nares closely spaced, anterior nare with a subtriangular flap being equal in length with posterior nare; posterior nare elongate and slit-like. Mouth arched, upper lip with deep incision, lower lip broadly interrupted, with fleshy medial portions and mostly not covering lower jaw; lips finely plicate; dentiform process moderately developed; lower jaw shovel-shaped, with slight corresponding incision ( Fig. 3 c). Barbels entirely covered with minute papillae; second pair of barbels reaching posterior edge of posterior nare; third pair of barbels extending to a level of mid-orbit.

Pores of cephalic lateralis system moderately small. Supraorbital and infraorbital canals confluent; an exception to this is that canals are not confluent at least from one side. Nasal and orbital groups of pores in supraorbital canal not separated, pores in orbital portion being variable in number and sometimes unequal on right and left sides of one fish. Supratemporal commissure uninterrupted, usually with 5 pores, sometimes with two pores laterally from the medial one on one side, but a single one on opposite side. Upper pore of preopercular canal positioned above the level of mouth corner. Number of pores in cephalic canals: supraorbital 8–9 (as exception, 5 or 6), infraorbital 13–14, preoperculo-mandibular 8–9, supratemporal (4) 5. Body lateral line canal complete. Body scaled. Scales with small and strongly eccentric focal zone ( Fig. 3 d).

Intestine with a single small loop not extending to stomach ( Fig. 3 e). Bony air-bladder capsule ( Fig. 3 f) rather depressed not deeper than the neural complex, with long and narrow, gently curved manubrium, and with welldeveloped posterior processes (“horns”); free air-bladder chamber highly reduced to absent.

Sexual dimorphism: Males possess very fine breeding tubercles on sides of body and head, which are very dense aggregated in the following areas: basal third of nearly all rays of pectoral and pelvic fins; broad band between pelvic fins; space between anus and anal-fin origin; bases of last unbranched and anterior two to three branched rays of dorsal and anal fins, and skin below dorsal-fin base; snout, isthmus and branchiostegal membranes, body wall above pectoral fins and narrow bands along mid-line on breast and belly between origins of pectoral and pelvic and of pelvic and anal fins. Preorbital groove weakly expressed to absent, when present occurring in both sexes; no suborbital flap in males, cheeks of males not inflated. Paired fins of males longer and dorsal fin comparably higher than in females (Table 6).

Coloration of preserved specimens: Head dark above, pale below, with irregular pattern on cheeks. Sides of body with dark transverse cross-bands of irregular shape, bands of opposite sides of body are usually connected to each other across the dorsum; width of bands being variable but usually less than width of pale interspaces. Breast with indistinct pattern of dark pigment in some specimens, but unpigmented in others. Dorsal, caudal and paired fins with bright pattern of transverse lines of freckles, sometimes obscured on paired fins. Peritoneum pale, melanophores sparsely distributed in abdominal part but very dense to almost confluent and fully hiding pale underground in paravertebral parts. Juveniles are characterized by a much more fragmented mottled pattern on the head and body (see Figs. 3 a and 3b).

Live fishes have a background color of yellowish to olive green with yellow to orange fins.

Etymology: This species is named from Kurdistan; adjective.

Comparative remarks: A combination of several features, including the modal 9 branched dorsal-fin rays (9) and the considerably slender caudal peduncle are most important for diagnostics of O. kurdistanicu s. In the Tigris- Euphrates basin there are no other species having both these features together. Oxynoemacheilus kurdistanicus seems to be most similar to O. argyrogramma (Heckel, 1849) (including O. euphraticus ( Bănărescu & Nalbant, 1964) as a synonym, according Krupp & Schneider (1989), Freyhof et al. (2011) and Kottelat (2012)), O. insignis (Heckel, 1843) and O. hamwii ( Krupp & Schneider, 1991) , but can be easily distinguished from all these species in a very slender caudal peduncle, modal number of branched dorsal-fin rays (9 vs. 7–8), and in the color pattern which is more regularly transversely banded instead of irregularly spotted. Oxynoemacheilus kurdistanicus further differs from O. insignis in the presence of the distinct posterior processes of the bony air-bladder capsule, features much less developed than in O. hamwii . The aforementioned combination of features distinguish Oxynoemacheilus kurdistanicus from all the nominal taxa described from Turkey (Erk’akan et al. 2007, 2008). Only O. erdali Erk’akan et al. (2007) and O. kaynaki Erk’akan et al. (2008) have been described as having 9 branched dorsal-fin rays, but O. erdali can be easily distinguished papillae of lips and shape of mouth (lips papillate and no processus dentiformis). O. kaynaki differs in having a much deeper body and caudal peduncle (ratio maximum/least body depth is 1.3–1.5 vs. 1.7–2 in the new species).

The considerably slender caudal peduncle seems to be the most peculiar feature of the new species. Within the genus only O. brandti (Kessler, 1877) and O. bergianus (Derjavin, 1934) possess the similarly gracile caudal peduncle; however, these species can be easily distinguished from O. kurdistanicus in the number of the branched dorsal-fin rays (7 or 8 vs 9), in having a conical snout, (not sharply declined declining toward tip in lateral view), a more irregular color pattern, and especially in the breeding tubercles being homogeneously distributed on the male’s head and body. In O. kurdistanicus tubercles are concentrated on the snout, underside of head and body, on the fin rays and along the dorsal-fin base.

Sexual dimorphic characters of the new species are similar to those in O. argyrogramma and O. hamwii —two widely distributed and potentially closely related species of the Tigris-Euphrates; this, together with some other morphological similarities (i.e., structure of the bony air-bladder capsule, shape of fins, configuration of the laterosensory system) may indicate common ancestry. However, in addition to the structural differences mentioned above, the morphometric comparison between O. kurdistanicus , O. argyrogramma and O. hamwii show the significantly smaller values of length of the 2 pairs barbels, distance from snout to anterior margin of anterior nostril, distance between posterior margin of anterior nostrils and anterior margin of posterior one, postorbital length, anal fin height, dorsal head length, pectoral-pelvic distance, pelvic-anal distance and larger values of width of bony interorbital space, length of pelvic fin base, maximum head width and lateral head length than both O. argyrogramma and O. hamwii (see Fig. 7 ). The paired fins of O. kurdistanicus are more closely spaced than in O. argyrogramma and O. hamwii ; the position of anus in O. kurdistanicus is closer to pelvic fins than that in O. argyrogramma and O. hamwii .

Figures

FIGURE 3. Oxynoemacheilus kurdistanicus sp. n.: a) holotype, SL 57.8 mm; b) juvenile, SL 25.1 mm; c) mouth structure; d) scale; e) gastrointestinal duct; f) bony air-bladder capsule, ventral view.

FIGURE 7. Comparison of some morphometric ratios between O. hamwii, O. argyrogramma, O. kurdistanicus and O. chomanicus. Values are mean ± 95 % confidence interval. The morphometric ratios are: a) width of caudal peduncle (wcp), horizontal eye diameter (oo), distance between posterior margin of anterior nostrils and anterior margin of posterior one (An to pn), length of pelvic fin base (LPelFB); b) maximum head width (wc), length of dorsal fin base (lD), length of longest rays in innermost caudal lobe (lC / m), depth at base of caudal peduncle (dbcp); c) lateral head length (lc), pectoral-pelvic distance (PV), length of longest rays in lower caudal lobe (lc / l), pectoral-fin length (lP); d), least depth of caudal peduncle (h), postorbital length (po), width of bony interorbital space (io), distance from snout to anterior margin of anterior nostril (dsn); e) dorsal head length (dlc), caudal peduncle length (lcp), pelvic-anal distance (VA), anal fin height (hA); f) preanal distance (aA), the ratio of the caudal peduncle length to the least depth of caudal peduncle (lcp / h).