Paraliparis stehmanni Andriashev 1986

Stein, David L., 2012, Snailfishes (Family Liparidae) of the Ross Sea, Antarctica, and Closely Adjacent Waters 3285, Zootaxa 3285, pp. 1-120 : 99-103

Paraliparis stehmanni Andriashev 1986

Figs. 71, 72

Paraliparis stehmanni Andriashev 1986:131 , Figs. 57, 58, 70; Stein & Tompkins 1989:7; Stein & Andriashev 1990:251, Fig. 30; Andriashev 2003:347, Figs. 184, 185.

Holotype. ISH 404 /76, male?, 216 mm TL, 195 mm SL, 54°12' S, 40°02' W, FR/ V Walther Herwig, 3 January 1976, ~ 2600 m.

Material examined. NMNZ P.043719, ripe female, 332 mm TL, 307 mm SL, 71°52.37' S, 174°04.29' E, NW edge of Mawson Bank , R / V Tangaroa, Stn. IPY / CAML TAN 0802 /167, 25 February 2008, 1954– 1990 m . NMNZ P.043719/1, cleared and stained right pectoral girdle. LACM 10784–1 , male, 98 mm SL, 61°55' S, 55°50' W , USNS Eltanin Stn. 995, 14 March 1964, 2119– 2562 m .

Expanded diagnosis (modified from Andriashev 2003 to include NMNZ P.043719). V 67–71, C 7, P 20–21, pc 6 [7]. Radials 4 (3+1), R 1, R 2, R 3 deeply and regularly notched. Teeth simple, mostly uniserial except near symphysis. Mandibular symphyseal pores distinctly separated, in smaller individuals in a shallow pit. Gill opening short, completely above pectoral base. Small rounded gill flap present. Pectoral notch rays rudimentary. Head 17– 21% SL, preanal length 40–45. Gill cavity blackish, peritoneum black.

Abbreviated description. Number before brackets from NMNZ P.043719, numbers in brackets given by or calculated from Andriashev 2003. Counts. V 67 [69–71 (11–12+58–59)], D 60 [63], A 53 [55–56], C 7 [7], P 20– 21 [20–21], radials 4 (3+1) but see below, pc 6, pores 2–6–7?–1. Ratios. HL 17.0 [18.4–20.7], HW 13.2 [11.8– 12.1], sn 4.5, E 3.3 [3.8–3.9], orbit 4.8, io 6.7, uj 7.6, go 2.6 [3.1–3.2], bd 22.7 [21.6–23.6], preD 27.9 [26.6–28.9], preA 45.5 [40.5–44.0], aAf 30.1 [21.6–27.7], UPL 11.1 [13.7–13.9], pcl 10.9. In % HL: HW 77.4 [59.0-65.8], sn 26.6, E 19.5 [19–21], orbit 28.2, io 39.3, uj 45.0, go 15.3 [15–17], bd 133.7 [117–118], preD 164.0 [133–157], preA 267.6 [220], aAf 177.4 [108–150], UPL 65.5 [69–74], LPL 82.8 [77–80], LLD 23.7, cp 5.2, pcl 64.0.

Andriashev NMNZ,

girdle

stehmanni pectoral

Paraliparis c

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FIGURE girdle pectoral

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Andriashev from

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195

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Holotype 1. /

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P 043719.

Premaxillary teeth uniserial for posterior 21 teeth, irregularly biserial for another anterior 20 teeth. Posterior teeth larger, stouter, not as sharp as those anterior. Symphyseal gap present, with deep anterior notch. Mandibular teeth much smaller than premaxillary teeth, uniserial for approximately 60 teeth, then an irregular band of tiny teeth near symphysis. Posterior mandibular teeth extend well behind posterior end of premaxillary tooth row. Chin pores paired, widely separated, interpore distance equal to about 5% HL, shallow pore pit not evident. Gill opening above pectoral fin upper ray, extending well below opercle tip. Gill flap a small rounded lobe near ventral end of gill opening, divided by opercle.

Right pectoral girdle with 15+2+4 rays, left fin with 14+2+4, notch rays both rudimentary, dorsal ray of the two filamentous, apparently much longer than the ventral, which is reduced to base only; lower lobe of four rays, the dorsalmost slightly more distant from remaining three than they are from each other. Radials abnormal; five (3+1+1) radials, R4 very small; normal arrangement would be 4 (3+1). Radials R1 and R2 round, large, R3 somewhat smaller, located at edge of girdle but not D-shaped, R4 very small, round, near edge of girdle but not touching it, R5 rounded, about equal in size to R1 , 2 , and 3. In the holotype and paratype, fenestrae present between R1 - R2 , R2 - R3 ; R1 , R2 , and R3 very deeply notched, R2 almost divided in half. In NMNZ P.043719, no fenestrae evident. Scapula with broad proximal head, distal head narrow; coracoid with long, slender helve, no basal notch present .

Pyloric caeca large, fat, not tapered to tips, of various lengths. Skin smooth, thick. Color in alcohol: snout dark, body posteriorly purplish, mouth blackish, branchial cavity dusky, peritoneum black. purplish posteriorly, upper pectoral fin lobe black edged. Stomach and caeca pale.

The NMNZ specimen has eggs up to 3.9 mm diameter.

Distribution. Capture in the Ross Sea greatly extends the range of the species from the previous records near the northern tip of the Antarctic Peninsula, and also greatly broadens the species depth range to shallower water (previous specimens were from 2119–2600 m, this one from 1431–1990 m).

Comparisons. Paraliparis stehmanni differs from all other Southern Ocean Paraliparis species in having the combination of deeply notched radials and two interradial fenestrae in the cartilaginous plate of the pectoral girdle (but see below). Few other Southern Ocean Paraliparis species have fenestrae: P. hureaui and P. camilarus , and in both the fenestrae are abnormal. Several of the new species described herein also have notched radials ( P. camilarus , P. epacrognathus , P. longicaecus , P. nullansa , P. posteroporus ), but none like those of P. stehmanni . Aside from these characters, P. stehmanni could be mistaken for almost any of the species with paired chin pores lacking an anterior fold, rudimentary pectoral fin rays, seven caudal fin rays, primarily uniserial teeth and similar counts, such as P. epacrognathus (see description) and P. parviradialis . This is especially true of damaged specimens; unfortunately, undamaged specimens are uncommon. Based on the few known specimens, only examination of the pectoral girdle structure can provide positive identification.

Comments. The individual described here differs in some regards from the types of P. stehmanni ( Table 3). Possibly significant morphometric differences could be the predorsal (164 vs 133–157% HL), preanal (268 vs 220), and anus-anal fin (177 vs 108–150) distances, which are much greater in NMNZ P.043719. It also differs in having the chin pores widely separated (more than 5% HL apart vs “closely set”). Many other proportions are just outside the previously known limits: head length (17.0 vs 18.4–20.7), head width (13.2 vs 11.8–12.1), eye (3.3 vs 3.8–3.9), gill opening (2.6 vs 3.1–3.2), upper pectoral fin lobe (11.1 vs 13.7–13.9), lower pectoral lobe (14.1 vs 14.7–15.4), preanal fin length (45.5 vs 40.5–44.0) and anus to anal fin distance (30.1 vs 21.6–27.7). These can possibly be explained by allometry resulting from the much greater size of this individual than the other two known specimens (307 vs 98–195 mm SL).

There are four qualitative differences between this specimen and the types: the apparently greater distance between the chin pores (more than 5% HL apart), the absence of a “common shallow transversely oval pit” for the chin pores ( Andriashev 1986), absence of fenestrae between R1-R2 and R2-R3, and the abnormal R4. The chin pores of the other specimens should be compared with those of this specimen. Presence of the pit cannot be determined in this individual owing to damage. Significance of the absence of the fenestrae is problematic; only three other specimens of P. stehmanni are known, and one of them is less than 100mm SL; variability of this character is not known. The “extra” radial (R4) is almost certainly anomalous because more than four radials are abnormal, R4 is small, and rest of the radials are identical to those of the types. The presence in NMNZ P.043719 of deeply notched radials in combination with similar meristic and morphometric characters, despite the “extra” R4, supports identification of this specimen as P. stehmanni . Future captures of additional specimens will clarify its identification.