Paraliparis macropterus, Stein, 2012

Stein, David L., 2012, Snailfishes (Family Liparidae) of the Ross Sea, Antarctica, and Closely Adjacent Waters 3285, Zootaxa 3285, pp. 1-120 : 66-69

Paraliparis macropterus n. sp.

Figs. 46, 47, 48

Holotype. NMNZ P.043716, male, 199 mm TL, 177 mm SL, 71°52.37' S, 174°04.28' E, NW edge of Mawson Bank, R / V Tangaroa, Stn. IPY / CAML TAN 0802 /167, 25 February 2008, 1954– 1990 m . Paratypes, NMNZ P.049141, male, 256 mm TL, 226 mm SL , NMNZ P.038592,> 232 mm TL, male, 217 mm SL, 72°04.39' S, 176°31.56' E, Iselin Bank , F / V San Aotea II, Stn. OBS 1595A/026, 3 February 2002, 1133– 1361 m ; P.038592/1, cleared and stained right pectoral girdle. NMNZ P.038582, male, 222 mm TL, 201 mm SL, 71°09.76' S, 176°25.48' E, northern Iselin Bank , F / V San Aotea II, Stn. OBS 1595A/012, 30 January 2002, 1228– 1312 m .

Diagnosis. V 66–67 (9–10+56–57), P 14–15 (10+1–2+3), notch rays rudimentary; gill opening long, 71–74% HL, extending over all or almost all rays, to base of lower pectoral-fin lobe; UPL 34–36% SL, extending to 14th or 15th anal-fin ray; LPL 23–28% SL, extending posteriorly to at least second or third anal-fin ray; pectoral radials 4. HL 18–25% SL. A distinct notch present at symphysis of premaxillae, matching a protrusion at symphysis of lower jaw.

Description. Counts. V 66 (66–67; 9–10+56–57), D 60 (60–62), A 54 (~53–55), C9 (8–9), P 15 (14–15), radials 4 (3+1), pc ~5, pores 2–5–7–1. Ratios. HL 25.6 (~18.4–23.7), HW 15.6 (13.7–15.1), HD ~20, sn 7.4 (6.7–7.0), E 3.7 (3.4–4.0), orbit 8.0 (6.0–7.3), uj 13.3 (13.0–13.2), go 18.1 (16.8–17.3), preD 28.7 (25.8–29.0), preA 37.6 (33.7–36.7), sna 19.1 (18.4–19.8), ma 15.4 (12.0–15.5), aAf 18.9 (17.1–17.9), UPL 36.8 (34.2–36.6), LPL 28.7 (23.6–25.5), pabd 21.6 (19.1). In % HL, HD ~87, sn 29.1 (28.2–30.0), E 14.5 (14.6–17.3), orbit 31.1 (25.6–30.7), uj 51.8 (55.5–55.7), go 70.7 (70.7–74.2), ma 60.1 (57.1–66.4), preD 111.9 (108.9–124.5), preA 146.5 (157.3), aAf 73.6 (76.8), UPL 143.4 (150.7–154.4), LPL 111.9 (101.3–102.1), LLD 10.6 (10.1–12.0), pabd 84.4 (82.0).

Head large, deep, its depth about 4/5 its length, dorsal profile sloping gradually downwards to high blunt snout. Mouth horizontal, subterminal. Upper jaw reaching to below rear margin of orbit or behind it, oral cleft reaching to below mid-pupil. Upper jaw deeply incised below snout. Both upper and lower jaws with wide gaps at symphysis, the lower with convex projection fitting into concavity of symphyseal gap in upper jaw. Premaxillary teeth simple, sharp canines, the largest slightly recurved, in about 38 oblique rows of 4–8 teeth each, forming a narrow band about five teeth wide; anterior teeth very irregularly arranged. Lower jaw teeth larger than premaxillary teeth, arranged similarly. Eye prominent but not large; orbit much larger than eye. Nostrils not tubular, about horizontal with middle or upper half of pupil. Gill opening exceptionally long, extending from above pectoral upper lobe ventrally over almost all rays. Tips of four branchiostegal rays entering margin of opercular membrane below opercle; opercular flap extending posterior to pectoral fin girdle and ray bases and covering them. Chin pores unusually widely separated, the distance between them about 4–5 pore diameters, a little less than 1/3 eye. All pores similar in size, none with raised rim. Pore formula unusual, 2–5–7–1.

Pectoral fin broad-based, deeply divided into two prominent exceptionally long lobes. Dorsal pectoral fin ray about on a horizontal through posterior of upper jaw or slightly higher, distinctly below lower margin of orbit. Upper lobe of ten closely spaced rays, lower of three rays, one to two rudimentary fin rays present only as ray bases in notch, creating a wide gap between lobes. Upper and lower fin lobes barely connected by membrane or continuation of skin between them. Upper lobe reaching far behind anal fin origin, to about 14th ray; lower lobe rays reaching to about second or third ray. Anteriormost lower lobe ray below posterior margin of orbit. Bases of lower lobe rays well separated by a distance equal to about 1/10 of HL, all three rays free for almost their entire length. Radials four (3+1), large, round, unnotched; ventralmost with a fenestra. Scapula triangular, helve absent; coracoid helve long, lobate, basal notch absent.

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FIGURE

Body tapering slowly to caudal fin. Dorsal fin insertion between neural spines 4–6, anal fin insertion between vertebrae 10–13. Abdominal part of spine strongly curved dorsally above abdominal cavity but not forming an externally obvious hump. Anus position posterior to pupil by about 2/3 distance between pupil and tip of opercular lobe, completely forward of the latter. A small, black, pointed genital papilla present. Abdominal cavity large, peritoneum visible through body wall and skin. Hypural fused, no slit evident; caudal-fin rays 8–9 (4/4, 4/4+1), a single ventral procurrent ray may be present. Skin thin, translucent, easily damaged.

Color in life uniformly pink (Fig. 47). In alcohol, skin translucent white; oral cavity dusky grayish, branchial cavity blackish. Peritoneum black, stomach pale with black veining.

Distribution. Known from three trawls taken on Iselin Bank and NW Mawson Bank at depths between 1133– 1990 m.

Etymology. From the Greek makros, long, and pteron, fin, to note the unusually long pectoral fin upper lobe.

Comparisons. The new species is so distinct that it cannot easily be confused with others. It has slightly fewer pectoral-fin rays than any other reported Antarctic Paraliparis species : P. gracilis and P. thalassobathyalis Andriashev 1986 have 15–17 ( Andriashev 2003), but the former has 67–74 vertebrae (vs 66–67), and the latter (including all subspecies) has 52–59, and neither has the gill opening extending ventrally in front of more than 3 pectoral-fin rays (vs from above the pectoral fin to the base of the lower pectoral-fin lobe). Its gill opening length is also similar to that of P. antarcticus , which is strikingly different in its much shorter pectoral fins (66–87 vs 143–154% HL), many more pectoral rays (23–28 vs 14–15), different peritoneum color (pale vs blackish), and other characters. In addition, no other Paraliparis has the pectoral fin upper lobe reaching the 14th or 15th anal-fin ray and the lower lobe reaching posterior to the first anal-fin ray. Paraliparis kreffti Andriashev 1986 has both pectoral fin lobes reaching posterior to the anal fin, although not as far, but also has more pectoral rays (16–18 vs 14–15) and only two radials (vs 4), a black stomach, and other trenchant differences ( Andriashev 2003:295). Several species of Careproctus ( C. profundicola , C. pseudoprofundicola Andriashev & Stein 1998 , and others) have similarly elongate pectoral fins, but have a well-developed disk and are obviously not Paraliparis .

Comments. The four specimens are all males. It is possible that the very long fins are a sexually dimorphic character or represent allometric growth. Similar sex-related differences have not been reported in the family, but allometric increase in pectoral fin length was reported by Kido (1988:24) for Careproctus rastrinus Gilbert & Burke 1912 .