Paraliparis ekaporus, Stein, 2012

Stein, David L., 2012, Snailfishes (Family Liparidae) of the Ross Sea, Antarctica, and Closely Adjacent Waters 3285, Zootaxa 3285, pp. 1-120 : 50-52

Paraliparis ekaporus n. sp.

Figs. 33, 34

Holotype. NMNZ P.043688, ripe male, 315 mm TL, 287 mm SL, 71°55.80' S, 173° 18.08' E, NW edge of Mawson Bank, R / V Tangaroa, Stn. IPY / CAML TAN 0802 /144, 23 February 2008, 1431– 1658 m. NMNZ P.043688/1, cleared and stained right pectoral girdle.

Diagnosis. Teeth uniserial in at least posterior halves of both jaws, then forming a gradually wider band anteriorly. V 67, C 7, P 20, radials 4, scapular helve absent. Chin pore single. Head short, HL 18% SL, and broad, HW 96% HL; snout short, 5% SL, 25% HL. Dorsal fin insertion between V 8–9, anal fin insertion between V 16–17. Preanal fin length about 46%, anus-anal fin distance about 31% SL. Body color purplish, snout and pectoral fin edges brown.

Description. Counts. V 67 (15+52), D 60, A 54, C 7, P 20 (14+3+3), radials 4 (3+1), pc unknown, pore formula unknown. Ratios. HL 18.1, HW 17.3, sn 4.6, E 4.4, orbit 6.0, io 6.9, uj 8.4, go 2.1, bd 19.5, preD 31.6, preA ~46, aAf 30.6, UPL 12.6, LPL 12.1% SL. In % HL: HW 95.8, sn 25.2, E 24.3, orbit 33.1, io 38.3, uj 46.2, go 11.6, bd 107.9, preD 174.6, preA ~257, aAf 169.0, UPL 69.9, LPL 66.8, LLD 18.7.

Head short, broad, and low, its width about equal to its length; its dorsal profile flattened at interorbital, then anteriorly rounded ventrally to snout. Snout short. Nostrils on a horizontal with pupil. Mouth horizontal, inferior, oral cleft short, reaching below anterior of eye. Lower jaw included, thick, unusually stout. Teeth simple, sharp canines, uniserial in both jaws for about posterior half of jaw; on premaxilla becoming a narrow band two or three teeth wide near symphysis. Teeth gradually and noticeably smaller anteriorly. Symphyseal gap present in each jaw. Eye prominent, pupil large, ½ to ⅔ eye diameter. Gill opening completely above pectoral fin base, a little more than 10% HL, not quite reaching ventrally to uppermost pectoral fin ray; opercular flap broad, triangular, supported by crescent-shaped almost horizontal opercle, its anterior end only slightly higher than the tip. Pore formula unknown owing to damage; remaining mandibular pores moderately large. Chin pore single, large, oblong, located immediately posterior to front edge of lower jaw and apparently pointing anteroventrally. Suprabranchial pore apparently single, directly above opercular flap.

Pectoral fin well developed, longest ray of upper lobe reaching about mid-abdomen. Uppermost ray on horizontal with mid-pupil. Upper lobe rounded, of 14 rays, notch rays three, the two lower rays rudimentary and very short, but more than just bases. Lower lobe of three rays, insertion of lowest ray below cheek and anterior to opercle, lower lobe reaching almost to posterior tip of upper lobe, posterior third of its rays free. Right pectoral girdle with four (3+1) radials, R1 and R2 large, round, about equal in size; R3 small with narrow rudimentary dorsal notch or slit, roughly D-shaped, flat near posterior edge of endochondral plate; R4 round, smaller than R1 and R2 but larger than R3. Fenestrae absent. Scapula hemicircular, helve absent; coracoid with long slender helve.

Body thick, deepest at about mid-abdomen. Dorsal fin insertion between vertebrae 8–9, anal fin insertion between vertebrae 16–17. First 2–3 caudal vertebrae lack anal fin rays, first anal fin ray poorly developed, buried in tissue. Dorsal and anal fins deepest at about 4/5 of SL posterior. Anus well behind symphysis of lower pectoral fin lobes, below anterior end of opercle and bases of lowest rays of upper lobe. Peritoneum visible through ventral part of abdominal wall. Hypural complex fused, slit absent. Caudal fin of seven (3/4) rays, auxiliary rays absent. SECM poorly developed. Skin thick, fibrous.

Color of body in alcohol purplish, darker on abdomen and caudal region; snout, edges of upper lobe, entire lower pectoral lobe brown, anal region blackish. Orobranchial cavity blackish, peritoneum black, stomach pale, pyloric caeca unknown, rotted.

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pores chin

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043688

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girdle pectoral

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043688

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ekaporus

Paraliparis

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33

FIGURE

Distribution. Known only from the type, collected on the northwestern edge of Mawson Bank, Ross Sea, at

1431–1658 m depth.

Etymology. From the Sanskrit eka, one, and Greek poros, hole, denoting the presence of a single chin pore.

Comparisons. Paraliparis ekaporus is most similar to P. monoporus but differs distinctly in number of vertebrae (67 vs 72–74), dorsal fin rays (60 vs 63–68), anal fin rays (54 vs 58–62), caudal fin rays (7 vs 6), radials (3+1 vs 2+0+1), and some proportions including body depth (19 vs 26–28% SL), snout length (25 vs 33–35% HL), anus to anal fin distance (31 vs 27–28% SL), and others. It is also similar to P. haploporus (see below for comparison). Paraliparis tetrapteryx has chin pores opening in a single common oval pore, but differs distinctly in number of vertebrae (76–81 vs 67), pectoral fin rays (26–31 vs 20), the far anterior position of the anus between the bases of the anterior lower pectoral fin lobe rays, and many other characters. Paraliparis devriesi is similar in counts and some proportions, but has clearly paired chin pores in a shallow pit; in addition, the new species differs distinctly in its blackish orobranchial cavity (vs pale) and more prominent triangular opercular flap (vs small and shallow).