Barbatula karabanowi, Prokofiev, 2018

Prokofiev, Artem M., 2018, A new species of Barbatula from the headwaters of the Bulgan River in western Mongolia (Teleostei: Nemacheilidae), Zootaxa 4407 (2), pp. 267-274 : 269-272

Barbatula karabanowi new species

( Figs. 3 , 4 )

Holotype. ZMMU 23829, 97 mm SL; Mongolia: Bayan-Ölgii aimag, headwaters of Bulgan River, 47˚04'46.4''N 91˚02'36.1''E, 21 July 2008.

Paratypes. ZMMU 23830 , 11 (1 cleared & stained), 84.5–111 mm SL, same data as holotype.

Additional material. IEE uncatalogued, 31, 18– 95 mm SL; Mongolia: Bayan-Ölgii aimag, headwaters of Bulgan River, 47˚05'12.7''N 91˚01'42.2''E, 20–21 July 2008.—IEE uncatalogued, 16, 24– 89 mm SL; Mongolia: Bayan-Ölgii aimag, headwaters of Bulgan River, 47˚00'46.8''N 91˚02'39.3''E, 21 July 2008.

Diagnosis. Barbatula karabanowi is most similar to B. dsapchynensis from the Zavhan River drainage (Lake Valley, western Mongolia) by having smooth lips, a short incision in the upper lip and short lateral lobes of the lower lip (vs. lips furrowed, if smooth then with a deep medial incision and no lateral lobes in all other species in Asia) and by the relatively small-sized elements of the dark colour pattern on the back and flank (maximal diameter of largest blotches on back and flank always less than ¼ of greatest body depth vs. equals to one-third or greater in the other species of the comparism group). Barbatula karabanowi is distinguished from B. dsapchynensis by lacking scales or having isolated scales on the flank between the dorsal- and caudal-fin bases only (vs. scales closely-set at least between the vertical of the dorsal-fin origin and the caudal-fin base). Barbatula karabanowi is further distinguished from B. dsapchynensis by a lower modal number of the pectoral-fin rays (11 vs. 12), a more anterior position of the dorsal and pelvic fins (predorsal and prepelvic distances 51–54 and 52–54% SL, respectively, vs. 54–57 and 55–58), a longer caudal peduncle (19–20% SL vs. 16–19), and the sphenotic contacting the epiotic (vs. contacting the lateral fontanelle), the posterior processes of the bony air-bladder capsule short and broad (vs. absent), and the posterior process of the urohyal twice as long as the lateral processes (vs. less than 1.5).

Barbatula karabanowi is distinguished from the sympatric B. cf. altayensis by having widely separated nares (vs. closely-set), lips with smooth and short lateral lobes, mental lobes oval, well-delimited (vs. lips, including mental lobes, strongly furrowed; lateral lobes absent; mental lobes barely separated from the rest of the lower lip), scales absent or isolated scales present on the flank between the dorsal- and caudal-fin bases (vs. flank and back completely covered by scales), less vertebrae (42–44 vs. 44–45) and less lateral line pores (75–88 vs. 89–105), a narrower head (maximum head width 45–50% of head length vs. 54–65), “non-muscular” cheeks in both sexes (vs. thickened, especially in males) and the colour pattern on the flank consisting of small and closely-set, irregularly shaped blotches (vs. irregularly shaped blotches large and widely spaced; Figs. 3 and 5 ).

Description. See Figs. 3–4 for general appearance and Table 1 for morphometric data. Body elongate, cylindrical in front of dorsal-fin origin and laterally compressed behind dorsal-fin base; dorsal profile straight or slightly arched between nape and dorsal-fin origin. Head conical, depressed; snout bluntly pointed at tip, ratio of greatest width of head (at level of hyomandibular joint) to width at level of anterior nostrils 1.4–1.6. Nostrils widely spaced (distance between center of posterior nostril and anterior border of eye equal to distance between center of posterior nostril to hind margin of nasal flap) ( Figs. 4A, 4B ). Nasal flap triangular, short, reaching up to center of posterior nostril when folded back. Mouth arched; lower jaw spoon-shaped; processus dentiformis poorly developed. Lips smooth; upper lip with short medial incision, dividing less than one-third of width of upper lip. Lateral lobes of lower lip short, equal to one-quarter of maxillary-barbel length. Mental lobes well separated, oval, smooth, lacking conical protrusions; a deep furrow present between mental lobe and rest of lip; otherwise lower lip smooth ( Fig. 4C ). Maxillary barbel reaching to vertical of posterior eye margin. Supraorbital sensory canal complete, disconnected from infraorbital canal. Supratemporal commissure continuous. Pores in cephalic sensory canal system: 8 in supraorbital, 13–14 in infraorbital; 9–10 in preoperculo-mandibular, 3 in supratemporal commissure. Lateral line complete, with 75–88 pores.

Dorsal fin with 3–4 (mode 3) unbranched and 7 branched rays; anal fin with 3 unbranched and 5 branched rays; pectoral fins with one unbranched and 11 branched rays; tip formed by 2nd or by 2nd and 3rd, rarely by 1st to 3rd or by 1 st and 2nd branched rays. Pelvic fins with one unbranched and 7 branched rays (often seventh ray being small and closely attached to sixth ray); tip formed by 2nd branched ray, rarely by 1 st and 2nd. Pelvic-fin origin below dorsal-fin origin, rarely slightly behind, pelvic fin not reaching to anus. Caudal fin with 9 + 9 principal rays (8 + 8 branched) and 7–8 + 6–7 (usually 7 + 6) procurrent rays, slightly emarginate (ratio between length of outermost and innermost branched caudal ray usually 1.1–1.2, as exception, up to 1.25), lobes rounded, equal in length.

Scales absent, if present, isolated from each-other, widely spaced on flank between dorsal- and caudal-fin bases; all scales with a large central focal zone. Skin texture smooth, without warts. Anus situated about one eye diameter in front of anal-fin origin. Intestine with two flexures. Free portion of gas bladder absent.

Coloration in preservative. Background coloration yellowish with greyish-brown, olive-brown to brownishblack pattern. Back with short oblique or transverse squarish blotches, sometimes fragmented, never extending onto flank. Flank usually with dense pattern of wavy streaks and small irregularly shaped blotches often fused with each other. Pattern usually bold ( Fig. 3A ), less frequently poorly contrasted ( Fig. 3B ); rarely flank almost plain, without pattern except short, obscure blotches on back ( Fig. 3C ). Fin rays indistinctly mottled, mottles present on dorsal-, caudal- and usually on pectoral-fin rays, on pelvic-fin rays in few individuals, absent on all fins in few individuals. Peritoneum unpigmented or brownish, usually pale-yellowish-brown in anterior half of abdominal cavity and hyaline in posterior half, with isolated melanophores, more densely set along vertebral column.

Sexual dimorphism. Males of III–IV stages of gonadal maturity possess very small and sparsely distributed epidermal tubercles on skin of dorsal, lateral and ventral surface of head and throat. Unbranched and 1–8th outer branched pectoral-fin rays expanded, tubercles on rays very small, sparsely set and inconspicuous. Probably none of males examined exhibits full development of breeding tubercles despite high stages of gonadal maturity. Some females with gonads up to IV (V?) maturity stage show expanded outermost branched pectoral-fin rays (without epidermal tubercles) and possess epidermal tubercles on head and skin almost as in males. Cheeks not thickened in females. Paired fins equal in length in both sexes.

Etymology. Named for Dmitry P. Karabanow (Borok) for his invaluable help during the expedition of 2008.

Analysis of food. Gut contents of B. karabanowi (n=8) contained larvae of stoneflies (Plecoptera) (n=4), stoneflies and chironomids (n=1), stoneflies and gammarids (n=2) or only chironomid larvae (n=1). In contrast, guts of all dissected B. cf. altayensis (n=8) were filled with chironomid larvae only except of one in one male (105 mm SL), which had eaten a large simuliid larva in addition to many chironomid larvae.

Figures

FIGURE 3. Barbatula karabanowi, a, ZMMU 23829, holotype, 97 mm SL; b, ZMMU 23830, paratype, 105 mm SL; c, ZMMU 23830, paratype, 114 mm SL; Mongolia:headwaters of Bulgan River.

FIGURE 4. Barbatula karabanowi, ZMMU 23829, holotype, 97 mm SL:a+b, head: a, dorsal view; b, lateral view; c, mouth. Scale bars:(a,b) 3 mm; (c) 5 mm; Mongolia:headwaters of Bulgan River.

FIGURE 5. Barbatula cf. altayensis, ZMMU 23828, 123 mm SL; Mongolia:headwaters of Bulgan River.