Paraliparis magnoculus, Stein, 2012

Stein, David L., 2012, Snailfishes (Family Liparidae) of the Ross Sea, Antarctica, and Closely Adjacent Waters 3285, Zootaxa 3285, pp. 1-120 : 70-72

Paraliparis magnoculus n. sp.

Figs. 49, 50

Holotype. NMNZ P.038643, ripe? male, TL, SL unknown, 41 mm HL, ~ 66 mm preA, 72° 21.00' S, 178°56.10' W, Iselin Bank, Ross Sea, F / V Janus, Stn. OBS 1593 A/104, 25 February 2002, 950– 1062 m . Paratype, NMNZ P.037589, sex unknown, TL unknown,> 180 mm SL, 37.2 HL, 72°09.45' S, 175°19.45' E, Mawson Bank, Ross Sea, F / V Sonrisa, Stn. OBS 1311/083, 26 February 2000, 1368– 1413 m, poor condition . NMNZ P.037589/1, cleared and stained right pectoral girdle.

Diagnosis. Snout short, blunt, 19–25% HL, orbit exceptionally large, 36–39% HL, aAf 113% HL. Pectoral fin rays 23–24. Teeth simple, blunt canines, forming bands about four teeth wide. Four large pectoral radials (1+1+1+1), fin almost unnotched, upper ray about horizontal with oral cleft. Haemal spines of posterior four or five abdominal vertebrae present, gradually lengthening posteriorly.

Description. Counts. V>61, D>55, A>50, C?, P 24 (23), radials 4, pc 6, pore formula unknown. Ratios. In % HL: HW 57.3, sn ~19 (25.0), orbit 38.8 (36.3), io 29.5, uj 42.4 (43.5), go 32.2, preD 93.0, preA 161.0, sna 67.1 (64.5), ma 54.6 (~61.0), aAf 113.2, UPL 73.2 (75.0), LPL 33.4, pabd 124.0.

Head deep, dorsal profile gradually sloping to abrupt, deep snout; snout blunt, flat, rising almost vertically above upper jaw. Nostrils damaged, apparently directly anterior to orbit on horizontal through middle of eye. Mouth terminal, horizontal, short, oral cleft reaching only to below front of orbit, but maxilla extending posterior to mid-orbit; teeth in both jaws stout, simple canines, in about nine long and very oblique rows of up to 10 teeth each, forming a narrow band up to four teeth wide. A wide gap at premaxillary symphysis. Eye and orbit unusually large, prominent; upper edge of orbit entering dorsal profile of head. Gill opening above pectoral fin and extending ventrally in front of 4–5 rays; opercular flap damaged in both specimens, but opercle itself points downward and curves posteriorly, its tip not horizontal. Mandibular symphyseal pores unknown. Pore formula unknown.

Pectoral fin short, its upper ray on about a horizontal with corner of mouth, well below orbit. Upper lobe about 3/4 of head, lower lobe about 1/3, notch moderately deep, rudimentary rays absent. Lower lobe far forward, its most anterior ray below or slightly posterior to a vertical through mid-orbit and posterior corner of upper jaw. Pectoral ray formula 16–18+3–4+3, rays in upper and lower lobes distinctly more closely spaced than rays in notch, which are more widely separated. Paratype with pectoral radials 4 (1+1+1+1), large, rounded; lowest with squared posterior margin. Notches and fenestrae absent. Scapula without helve, roughly hemicircular; coracoid with moderately long helve with dorsal web almost to tip, basal notch absent.

Tails broken off and missing in both specimens; holotype missing at least 18 vertebrae, paratype possibly missing only hypural complex. Body gradually tapering from above posterior of abdominal cavity. Anus located far forward below head, slightly behind a vertical through posterior margin of orbit. Abdominal cavity large, long, deep, its length behind pectoral fin base symphysis about 1 ¼ HL. Predorsal length about greater than HL, first dorsal fin pterygiophore rayless, its insertion between vertebrae 3–4, first dorsal ray insertion between vertebrae 4–5, anal fin insertion between vertebrae 10–12. Abdominal vertebrae 10, caudal vertebrae at least 51, probably not more than 52 or 53 including hypural. Abdominal vertebrae distinctive in having haemal spine gradually increasing in length posteriorly from fifth (NMNZ P.037589) or sixth (NMNZ P.038643) abdominal vertebra. Pyloric caeca large, digitate, blunt, thin-walled.

Color of skin in alcohol unknown, both specimens completely skinned. Oral cavity and tongue dusky, branchial cavity black, peritoneum black, stomach and pyloric caeca pale.

Distribution. Known from two Ross Sea locations: southeast of Iselin Bank at 1368 m, and from Scott Canyon at 950–1413 m.

Etymology. The specific epithet magnoculus from the Latin magnus, large, and oculus, eye, referring to the large orbits of the species.

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49 FIGURE

Comparisons. Despite the poor condition of the holotype and the paratype, P. magnoculus is clearly an undescribed species. Even though number of vertebrae, dorsal, and anal fin rays cannot be ascertained owing to damage, it differs from all other possible species in at least one significant character, and in many cases, more than one. For instance, among species with four radials with similar pectoral fin ray numbers, it differs from many in radial spacing (1+1+1+1 vs clearly 3+1); of those remaining, P. valentinae Andriashev & Neelov 1984 has a coracoid of entirely different shape (almost rectangular, helve absent vs normal with long helve), scapula with helve (vs without), and broader interorbital space (46–52 vs ~30% HL); P. hubbsi Andriashev 1986 has fewer vertebrae (57–60), 12–13 pyloric caeca (vs 6), scapula with helve (vs without), and a black-veined stomach (vs pale); in P. diploprora Andriashev 1986 the aAf distance is less than HL (71 vs 113% or more HL), and in P. operculosus a scapular helve is present (vs absent), a prominent opercular lobe is present (vs small), the stomach is dark (vs pale), the gill opening is shorter (22 vs 32% HL) and other differences.