Comprehensive DescriptionRead full entry
Parmaturus albimarginatussp. nov.
Figs 2 and 3, Tables 1-3
White-tip Catshark (English), holbiche à pointes blanches (French).
Material. 1 specimen.
New Caledonia . Cruise HALICAL 1, stn 15, 18°54’S , 163°05’E (Grand Passage), 688-732 m depth, longline, R.V. “ Alis ”, 21 November 1994 , adult male 577 mm TL ( MNHN 1997.3584: holotype ).
Diagnosis. A scyliorhinid catshark with the following combination of characters: a soft body; velvet-like skin with large tricuspidate denticles; plain pale to medium brown coloration; dorsal, caudal and anal-fin posterior margins distinctly white-edged; pronounced caudal crests on upper and lower anterior caudal fin margins, denticles on crests greatly enlarged; teeth mainly tricuspidate with greatly elongate median cusps, in 92 rows in both jaws; first dorsal fin slightly behind middle of back; pelvic fins slightly in front of mid-body, prepelvic length 47% TL; vent at mid-length, pre-vent length 50% TL; snout relatively short, prenarial length 3.7% TL; mouth short, length 3.7% TL; labial furrows short, 1.7-2.0% TL, lower furrows subequal in length to upper furrows; head depressed, shorter than abdomen, length 19.2% TL, pectoral-pelvic length 24.8% TL; second dorsal fin larger than first, anterior margins of first and second dorsal fins 8.7% and 10.4% TL respectively; subterminal caudal lobe relatively small, subterminal margin length 3.3% TL, terminal margin length 3.8% TL; monospondylous centra 43; precaudal centra 95.
Description. Scyliorhinid catshark with flabby, soft body, trunk slightly depressed, tail compressed and tapering to caudal fin, head well depressed, height 6.9% TL, head shorter than abdomen, pectoral to pelvic space 24.8% TL, 1.3 in head length; pelvic to anal space 0.7 in anal-fin base; caudal peduncle moderately elongate, anal to caudal space 1.1 of anal-fin base; peduncle moderately compressed, caudal peduncle width 1.6 in height, dorsal and ventral profile longitudinally ridged by anterior part of upper and lower caudal fin crest. Snout short and rounded-parabolic in dorsoventral view, tip broadly rounded, conical in lateral view; preoral length 6.3% TL, 0.7 in mouth width; prenarial snout 0.9 times eye length. Eyes large, length 3.9% TL, 4.9 in head length; eyes dorsolateral on head, with well-developed subocular ridges. Labial furrows short but well defined. Nostrils large with tube-like incurrent apertures, anterior nasal flaps sub-triangular, posterior tip not forming a pronounced lobe, nostrils well separated, internarial length 2.1% TL; well removed from mouth.
Teeth of upper jaw fully exposed when mouth closed; anterior teeth tricuspidate with a long pointed central cusp flanked by much smaller lateral, often barely distinguishable cusps; lateral teeth with shorter median cusps, and relatively longer lateral cusps, lateral cusps often with a short accessory cusp (teeth weakly fivecusped), base of teeth ridged, teeth in 92/92 rows in upper and lower jaw respectively; teeth in quincunx arrangement but lateral teeth appear as arranged in oblique rows due to the equal or decreasing size of the cusps. Dermal denticles on side: weakly imbricated and erect; shield-like tricuspidate crown with a very long pointed median cusp ending in a longitudinal ridge and mostly short lateral cusps. A strong caudal crest of enlarged denticles on basal half of upper caudal margin falling short of second dorsal-fin insertion by length of about first gill slit; denticles of caudal crest greatly enlarged laterally (tricuspidate, often more than three times longer than body denticles below, lateral cusps barely shorter than median cusp, directed posterolaterally, with about three rows of smaller denticles between greatly enlarged lateral denticles, denticles largest anteriorly decreasing in size posteriorly on crest to merge with denticles of tail, crest well elevated, naked area of skin separating crest denticles from those on side of tail); a similar but less well-developed crest on caudal peduncle ventrally, barely extending onto ventral caudal margin; crest less well elevated than dorsal crest, in 4-5 rows, denticles smaller in size than those in dorsal crest.
First dorsal fin much smaller than second dorsal, first originating slightly forward of pelvic fin insertion; second originating over posterior half of anal fin base; anterior margin of both dorsal fins weakly convex, apices narrowly rounded; posterior margin of first dorsal fin strongly convex, second dorsal posterior margin much less convex; rear corner obtusely angular; inner margin straight, directed posterodorsally. Pectoral fins small and rounded distally, somewhat lobe-like, anterior margin 9.4% TL; anterior and posterior margins moderately convex, apex and rear corners broadly rounded. Pelvic fins small, subtriangular, apex broadly rounded, length 9.4% TL. Anal fin triangular, similar in size to second dorsal fin, base 10.7% TL, 0.9 times interdorsal space; origin at about level of anterior half of interdorsal space, anal-fin height 2.3 in base length.
Caudal fin relatively short, dorsal caudal margin length 21.9% TL, upper and lower lobes originating as low ridges of enlarged denticles; lower lobe moderately developed distally; terminal caudal lobe fan-like with pronounced convex posterior margin. Monospondylous centra 43; precaudal centra 95; total 136.
Coloration. (from preserved specimen). Plain pale to medium brown dorsally, no evidence of body markings; lower flanks yellowish white, gradating into slightly darker coloration above; brownish coloration on dorsal tail delineated clearly from lighter lower side; yellowish white ventrally; dorsal, caudal, anal and dorsal surfaces of pectoral and pelvic fins brownish, somewhat darker than body; posterior margins of dorsal, caudal and anal fins with broad, white posterior margins; posterior margin of pectoral and pelvic fins light but not forming conspicuous white stripe. Floor and roof of mouth greyish, pores on roof of mouth black-edged. Claspers yellowish ventrally, milky white above; naked skin at pelvic insertion white.
Size. Known only from the holotype, an adult male 577 mm TL.
Distribution. From the insular slopes off northern New Caledonia (Grand Passage) in 590-732 m depth (Fig. 1).
Etymology. From the Latin “albus” (white) and “marginatus” (with a border) in reference to its broad, white, posterior fin margins.
Comparisons. Parmaturus albimarginatus can be distinguished from its congeners by the following: Parmaturus melanobranchus differs from P. albimarginatus by: first dorsal-fin origin forward of mid-length (after midlength in P. albimarginatus ), pre-first dorsal length about 46% TL (versus about 51% TL); teeth with 3-5 cusps (versus mainly 3); shorter pre-pelvic length (39% TL versus 47% TL); longer mouth (7.0% TL versus 3.7% TL); head longer than abdomen (rather than shorter); and a dark brown or grey coloration (rather than pale brown).
Parmaturus pilosus ZBK differs from P. albimarginatus by: first dorsal-fin origin forward of mid-length (after midlength in P. albimarginatus ), pre-first dorsal length 45-46% TL (versus about 51% TL); teeth with mainly 5-6 cusps (versus mainly 3); dorsal fins subequal (versus second dorsal larger); and a larger subterminal caudal lobe (5.5% TL versus 3.3% TL).
Parmaturus macmillani ZBK differs from P. albimarginatus by: first dorsal-fin origin forward of mid-length (after midlength in P. albimarginatus ), pre-first dorsal length about 48% TL (versus 51% TL); teeth with 5-6 cusps (versus mainly 3); and dorsal fins subequal (versus second dorsal larger).