Pogonophryne neyelovi, Shandikov, Gennadiy A. & Eakin, Richard R., 2013

Shandikov, Gennadiy A. & Eakin, Richard R., 2013, Pogonophryne neyelovi, a new species of Antarctic short-barbeled plunderfish (Perciformes, Notothenioidei, Artedidraconidae) from the deep Ross Sea, ZooKeys 296, pp. 59-77 : 60-67

Pogonophryne neyelovi sp. n. Figures 12b345cTable 1

Holotype.

MNKhNU R299 (Fig. 1), post-spawning male, 355 mm TL, 295 mm SL, weight (in formalin) 685 g, F/V Tronio, bottom Spanish long-line, set no. 49, Ross Sea (72°50.5'S, 176°49.2'E), depth 1,337 m, 12 January 2010, coll. G.A. Shandikov. Damage made by releasing the hook: symphysis of lower jaw disjointed and skin removed from stem of mental barbel though preserved in good condition.

Additional material.

Freshly caught female (not preserved, Fig. 3), 350 mm TL, 294 mm SL, F/V Tronio, bottom Spanish long-line, set no. 46, Ross Sea (72°50.1'S, 176°50.8'E), depth 1,350 m, 18 January 2010, coll. G.A. Shandikov. Freshly caught specimen, sex undetermined, probably female (not preserved, identified by photos, Fig. 4), 305 mm TL, 253 mm SL, F/V Joong Woo 3, bottom trot-line, set no. 43, Ross Sea (73°14.6'S, 177°52.4'W), depth 700-1,390 m, 13 January 2012, coll. Yu. Korzun.

Diagnosis.

A new species of the genus Pogonophryne distinguished from other species of the " Pogonophryne mentella " group by the following combination of characters. Short and tiny mental barbel, light-brownish dorsally, reaching anterior edge of orbit over snout with mouth closed; its length about 9% SL (Table 1). Very short poorly developed ovaloid terminal expansion composed of bicolored, white and brownish, scale-like and mostly bluntly palmate processes; its length less than 1/3 of barbel length. Lower jaw moderately protruding with weakly visible anterior teeth on symphysis and hidden dorsum of tongue when mouth closed. Second dorsal fin high in male (its height about 25% SL), lacking any prominent anterior elevated lobe, with longest rays (1st to 7th) very soft, sinuous distally and branched from about mid-length; fin almost entirely black in coloration with bluish insertions in anterior one third and dark basally with light upper margin posteriorly. Dorsal surface of head and area anterior to first dorsal fin covered by dark-brown irregular spots, vermiculations and markings; belly, breast and lower surface of head brown or brownish in general, without distinct dark spots. Mandibular oral valve light. Pectoral fin vertically dark-striped in its anterior part and uniformly lightish in posterior part.

Description of holotype.

For all measurements and counts see Table 1. Body robust and tadpole-like from dorsal and ventral views. Head depth (maximum body depth) 20% SL. First dorsal fin with two soft spines, comparatively low, length of its base very short. Second dorsal fin with 27 rays and very high, its dorsal profile not concave and without a prominent elevated anterior lobe. Longest second dorsal fin rays (1st to 7th) very soft, sinuous distally and branched from about mid-length. Anal fin with 18 fleshy rays. Left and right pectoral fins with 20 rays. Pelvic fin not long, fleshy and notably wide (almost as wide as long). Posterior margin of caudal fin sharply rounded.

Eye filling orbit, snout rounded in dorsal view. Lower jaw moderately protruding (distance between tip of lower jaw and tip of upper jaw 1.9% SL or 4.8% of head length) with weakly visible anterior teeth on symphysis and hidden top of tongue when mouth closed. Posttemporal ridges not prominent. Both oral valves anteriorly possess sparsely distributed short and simple papillae; inner margins of both lips fringed.

Mental barbel (Fig. 2b) small and short, its length about 9% of head length, somewhat rounded distally, reaching anterior edge of orbit in backward extended mode over snout with mouth closed. Barbel base about 21% as wide as long. Proximal part of stem covered by sparsely distributed short papillae; median part of stem covered by sparsely distributed elongated papillae; distal part of stem covered by densely distributed flattened and acute-angled processes. Terminal expansion short, ovaloid and barely wider than stalk (width about 3.2 mm or 12% of barbel length, depth about 2.8 mm or 10% of barbel length), composed of scale-like, mostly bluntly palmate (resembling cat’s paw) processes; bifurcated, truncate and serrated processes also occur.

Teeth on both jaws sharp and conical, slightly curved inwards, somewhat enlarged on tips of jaws in posterior rows, somewhat larger on upper jaw; up to five irregular rows at symphyses of lower and upper jaws.

Gill rakers short, denticulate, slightly laterally compressed or conical; in total 19 rakers on first arch: 1+0+9=10 in anterior series and 0+1+8=9 in posterior series; rakers on lower part of gill-arch distributed along entire length of ceratobranchial bone.

Lateral line system. Upper lateral line with 25 (left) and 26 (right) pores (tubular scales), middle lateral line with about 14 (left) and 15 (right) pores and tubular scales. Number of pores in cephalic sensory canals: preoperculo-mandibular 9/9; infraorbital 7/7; supraorbital 4/4, with 2/2 nasal and 2/2 interorbital pores; coronal commissure with 1 central pore; temporal 6/6; supratemporal 2, disrupted at middle, with 1 left and 1 right pores.

Radiograph. Total vertebrae 38: 16 abdominal and 22 caudal.

Coloration. In live specimen general ground coloration of upper and lateral surfaces of head, upper jaw, back and lateral trunk sandy-pale. Bases of pectoral fins uniformly dark-brown. Abdominal surface of body lacking evident dark spots or markings: belly generally dark brown with some lighter indistinct areas and longitudinal zigzag-like striations, Breast lighter than belly, lower surface of head light. Dorsal and lateral surface of head anterior to first dorsal fin, back and lateral parts of trunk covered by dark-brown, specific irregular (not rounded) markings − vermiculations and spots, markings covering up to 50% of upper surface of head anterior to first dorsal fin. Spotted skin extends over dorsal parts of eyes. Nostrils unpigmented. Upper jaw mostly spotted, posterior tips of maxillaries and angle of mouth uniformly white. Mandibular oral valve whitish to somewhat light brownish, maxillar oral valve whitish. Fringes on inner margins of both lips and oral cavity overall whitish. Mental barbel indistinctly bicolored dorsally: with brownish stem and bicolored, whitish and brownish, scale-like processes on terminal expansion, ventral surface of stem lighter.

Soft spines in first dorsal fin whitish, fin-fold blackish basally and light-bluish distally. Second dorsal fin generally black in anterior third with partly bluish fin-fold sectors along first to third and sixth-seventh rays, and dark basally with light upper margin posteriorly. Anal and pelvic fins light, somewhat pinkish (fleshy), without the contrasting (dark-light) vertical bicolored pigmentation typical of most congeners. Pectoral fins with about six to seven narrow dark vertical stripes anteriorly, distal third of fins light. Caudal fin with creamy-pinkish (fleshy) ground coloration, dark very basally and in median superior part more evident in three upper branched rays, with about six indistinct dark vertical stripes medially.

Gill chamber light, somewhat light-brownish. Peritoneum creamy white, with very sparsely distributed black dots.

In formalin-preserved specimen general features of pigmentation remain unchanged except for bluish and pinkish coloration on fins being faded.

Variability.

The second dorsal fin in the adult male is considerably higher than in the female (24.8% SL vs. 18.9% SL in female, Table 1), this may be due sexual dimorphism. In the female the point of primary branching of the anterior longest rays in the second dorsal fin is located somewhat above the mid-point of the rays (vs. mid-point of rays in male). General body and fin coloration is similar in both sexes. Wide, very fleshy and uniformly light pinkish pelvic fins, as well as fleshy anal-fin rays and uniformly light pinkish coloration of the anal fin and ground coloration of the caudal fin, may be considered as nuptial or age-related changes in post-spawning adults, both male and female. Similar nuptial or age-related changes in adult fish were recently found in Pogonophryne tronio by Shandikov et al. (2013). Immature subadult or juvenile individuals probably possess vertically bicolored (dark and whitish) anal and pelvic fins, and the pelvic fins are narrowed as can be seen in the smaller unpreserved specimen 305 mm TL (Fig. 4).

Distribution.

Pogonophryne neyelovi is a deep-water benthic species known from three captures in the Ross Sea at depths of 700-1,390 m.

Mode of life.

Like other morphologically close deep-water congeners ( Shandikov et al. 2013) Pogonophryne neyelovi might be considered predatory in its feeding behavior. It probably also feeds by necrophagy. Three known specimens of Pogonophryne neyelovi were captured by hooks baited with large pieces (about 4 ×3× 2 cm) of giant Peruvian squid, Dosidicus gigas . In the holotype, the liver is large, filling about 35% of the abdominal cavity length and creamy in coloration; hepatosomatic index reaches 2.0. Spawning probably took place within one month prior to the capture, around December - January. The testes are paired, well developed and folded, reaching about 68 mm in length, 14 mm in width and 6.5 mm in depth. GSI was about 0.6, and SGM apparently corresponds to early post-spawning stage VI or VI−II.

Etymology.

The new species is named after Alexey V. Neyelov who contributed significantly to the knowledge of Antarctic fishes, and to whom the first author is sincerely thankful for the valuable help during his PhD studies in Zoological Institute, Russian Academy of Scienses, St Petersburg, Russia. Vernacular names proposed for Pogonophryne neyelovi : hopbeard plunderfish - in English and хмельовуса бородатка [khmelyovusa borodatka] - in Ukrainian.