Psednos cryptocaeca, Stein, David L., 2012

Stein, David L., 2012, A Review of the Snailfishes (Liparidae, Scorpaeniformes) of New Zealand, Including Descriptions of a New Genus and Sixteen New Species, Zootaxa 3588, pp. 1-54 : 37-39

Psednos cryptocaeca n. sp.

Fig. 28

Holotype. NMNZ P. 031114, ripe? male, 96 mm SL, 110 mm TL, 46°5.04' S, 170°50.39' E, off the Otago Canyons, R/V Tangaroa, Stn. TAN 9306/118, 5 March 1993, 118– 121 m.

Diagnosis. Vertebrae 56, pectoral fin rays 15 (6+4+5). Mouth terminal, oblique, its angle about 45°, posterior lower edge of lower jaw with anterior projecting blunt spine. Teeth very slender, needle-like. Opercle long, slender and slightly curved, pointing posteroventrally but primarily down; lower margin emarginate, supported by at least two, possibly three, branchiostegal rays. Coronal pore apparently absent. Abdominal vertebrae forming a marked dorsal curve. Mandible to abdomen end about 175% HL. Peritoneum dark brown, visible through body wall; stomach brownish, intestine entirely cream-colored.

Description. Counts: V 56, D 49 or 50, A 43 or 44, C 6, P 15, radials unknown, pc 7, pore formula unknown. Ratios: HL 19.9% SL, HW 13.7, sn 5.1, E na, orbit 5.7, io ~ 8.3, uj 9.2, go ≤6.1, UPL na, LPL na, bd 27.1, preD 27.9, preA 38.0, sna 19.1, ma 20.1, aAf 23.0, mabd 34.9, pabd 24.0. In % HL: HW 69.1, sn 25.6, E na, orbit 28.8, io ~42, uj 46.1, go ≤30.9, UPL na, LPL na, bd 136.1, preD 140.3, preA 191.1, sna 95.8, ma 101.0, aAf 115.7, mabd 175.4, pabd 120.4.

Dorsal profile of head sloping gradually dorsally at about a 45° angle to occiput. Occiput prominent, forming a hump, then gradually sloping posteriorly to caudal. Snout blunt. Nostrils single, small, about on a horizontal with or just below dorsal margin of orbit and immediately anterior to it. Mouth terminal, oblique, its angle about 45°, tip of upper jaw slightly posterior to tip of lower jaw but dorsal to it, not included. Teeth very slender, needle like, in about 28 oblique rows of up to seven or eight teeth each in both jaws. Premaxillary teeth forming narrow band on anterior 1/3 of jaw; mandibular teeth similarly arranged, but band is shorter, about 1/4 of jaw length. Lower jaw unusual in having an anteriorly projecting blunt spine above and forward of ventrally oriented blunt tip of retroarticular. Judging from diameter of orbit, eye apparently large, but missing. Gill opening damaged, probably more or less vertical; opercle long, slender and slightly curved, pointing posteroventrally but primarily down; lower margin supported by at least two, possibly three emarginate branchiostegal rays. Membrane of opercular flap damaged, above pectoral base and possibly extending ventrally in front of a few rays. Gill rakers not examined. Pores mostly missing with skin, coronal pore apparently absent.

Pectoral fin dorsal ray on horizontal between lower margin of orbit and posterior corner of mouth. Rays of upper and lower lobes damaged, lengths unknown. Both right and left fins of 15 rays each, (6+4+5 R, 7+3+5 L), rudimentary rays absent. Lowest (most anterior) ray of lower lobe slightly posterior to a vertical through posterior margin of orbit. Pectoral girdle not examined.

Trunk deep just behind head, tapering evenly to tail. Vertebral column clearly humped, abdominal vertebrae forming a marked dorsal curve. Vertebrae 10+46. Dorsal origin well behind head at a little more than 1/4 body length; dorsal fin origin between vertebrae 5–6. Anal fin origin between vertebrae 13–14, preanal fin distance more than 1/3 SL. Anus below upper edge of pectoral fin girdle, well behind symphysis of lower pectoral fin lobes, about half lower lobe length posterior to symphysis. Genital papilla absent. Abdomen relatively short and deep. Pyloric caeca difficult to find; stomach and caeca located dorsally in body cavity. Hypural complex fused, hypural plate single, unslit. Skin mostly missing, but a subcutaneous fibrous layer remaining over most of body, suggesting presence of thick pseudotissue in life.

Life color unknown. In alcohol, body and all fins pale, orobranchial cavity dusky, tongue dotted with melanophores. Dark orobranchial cavity makes branchiostegal membranes and posterior of gill cavity darker than remainder of body. Musculature visible through skin. Peritoneum dark brown, visible through body wall; stomach dark brown, portion of intestine close to stomach dark brown, distal part cream colored.

Distribution. Known only from the holotype, collected in shallow water about 120 m deep off the Otago Canyons to the east of southern New Zealand.

Etymology. The name cryptocaeca , from the Greek krypto -, hidden and the Latin caecum, blind, referring to the difficulty of finding the pyloric caeca in this species.

Comparisons. Psednos cryptocaeca differs from the other known species of the region in the extreme dorsal position of the pyloric caeca and in having a retroarticular with two spines, one at the posterior angle of the lower jaw and the other, blunter and forward of it and pointing anteriorly. It may be easily confused with P. platyoperculosus and P. n e m n e z i, but see those descriptions below for comparison.

It is similar to P. whitleyi Stein et al. 2001 from Australia in having almost identical vertebral and fin ray counts, but differs distinctly in its shorter head length (20 vs 25% SL), shorter snout (5 vs 8% SL), wider head (69 vs 46% HL), deeper body (136 vs 105% HL), longer mandible to anus distance (101 vs 75% HL), greater anus to anal fin distance (116 vs 95% HL), and longer preanal fin length (191 vs 158% HL).

Figures

FIGURE 28. Psednos cryptocaeca n. sp. Holotype. NMNZ P. 031114, 96 mm SL. A. lateral view. B. lateral view of preserved specimen. (Photo by C. Struthers, Te Papa)