Cirrhigaleus australis, William T. White, Peter R. Last & John D. Stevens, 2007

William T. White, Peter R. Last & John D. Stevens, 2007, Cirrhigaleus australis n. sp., a new Mandarin dogfish (Squaliformes: Squalidae) from the south-west Pacific., Zootaxa 1560, pp. 19-30 : 20-29

Cirrhigaleus australis new species

Southern Mandarin Dogfish

Figs 1-4; Table 1

Cirrhigaleus barbifer : (not Tanaka) Last and Stevens, 1994, Sharks and rays of Australia, pp 48, 68, figs 8.11, pi. 6; Bass, 1979, Records of little-known sharks from Australian waters, pp 250, 251, fig. 3.

Holotype. CSIRO H 5789-01 , female 970 mm TL, east of Bicheno , Tasmania, 41°55'S, 148°37'E, 360-414 m , 18 May 2002.

Paratypes. 3 specimens. AMS I 19154-001 , female 713 mm TL, off Brush Island , New South Wales, 35°34'S, 150°45'E, 493 m , 6 July 1976 ; AMS I 27022-001 , female 1230 mm TL, northeast of Sydney , New South Wales, 33°00'S, 152°00'E, 640 m , March 1986 ; AMS I 42891-001 , female 1124 mm TL, southeast of Green Cape , New South Wales, 37°30'S, 150°30'E, 400 m , 3 November 2003 .

Diagnosis. A moderately large dogfish of the genus Cirrhigaleus with the following combination of characters: body very robust, trunk depth 11.8-14.2% TL; eyes relatively small, length 1.37-1.49 in horizontal preorbital length; upper labial furrows relatively short, 7.09-8.15 times mouth width; first dorsal fin moderately large, slightly raked, posterior margin 9.1-10.9% TL; second dorsal similar in size to first dorsal fin, raked, height 1.70-1.91 times its length, posterior margin 8.0-8.9% TL; first dorsal spine long, its exposed length 4.6-5.7% TL, 5.48-6.43 times in pectoral -pelvic space, its apex located just below apex of fin; second dorsal spine long, its exposed length 4.6-6.0% TL, 4.95-6.08 times in pectoral -pelvic space, 3.08-4.24 times in prepectoral length, its apex located at about level of fin apex; pectoral fins moderately large, inner margin 7.0-8.0% TL; prepectoral length 1.47-1.89 times distance from pectoral-fin insertion to first dorsal-fin midbase; flank denticles with three primary cusps, lateral cusps often with cusplets; 50 monospondylous centra, 85 precaudal centra, 114-115 total centra; maximum size at least 123 cm TL.

Description. Body fusiform, robust, nape strongly humped; deepest near first dorsal-fin base, maximum depth 1.03 (0.85-1.01) times width; trunk depth 0.88 (0.93-0.95) times abdomen depth; head relatively short, 19.5 (19.1-19.8)% TL. Tail moderately elongate, subcircular in cross-section anteriorly, tapering slightly to second dorsal fin; tapering more rapidly beyond second dorsal fin, becoming broadly semicircular posteriorly; dorsal groove weakly developed, broad, very shallow; ventral groove well developed, broad, shallow, with weak medial ridge visible anteriorly; lateral keels very well developed, originating slightly posterior to level of insertion of second dorsal fin, terminating about three quarters of an eye length behind dorsal caudal-fin origin; pelvic -caudal space 1.67 (1.57-1.62) in pectoral -pelvic space, 1.00 (0.98-1.12) in prepectoral length; dorsal -caudal space 2.90 (2.50-2.82) in interdorsal length; dorsal caudal pit very weak, ventral caudal pit absent.

Head depressed, more flattened dorsally than ventrally, broad, width 1.06 (1.09-1.14) times trunk width, 1.07 (1.01-1.20) times abdomen width; becoming subtriangular in cross-section towards pectoral-fin origin; length 2.86 (2.72-3.03) in pre-vent length; height 0.83 (0.68-0.73) times width. Snout flattened dorsally, narrowly rounded ventrally, apex bluntly pointed; lateral prenarial margin broadly rounded, not forming a ridge; bluntly pointed, strongly tapered in dorsal view, horizontal length 1.49 (1.37-1.44) times eye length, 0.65 (0.60-0.65) times interorbital space; horizontal prenarial length 2.03 (0.97-2.10) times in preoral length.

Eye oval, moderately large, length 5.49 (4.83-5.93) in head, 2.14 (2.29-3.29) times height; weakly notched posteriorly, notch deepest anteriorly, not connected to anteroventral margin of spiracle. Spiracle moderately large, almost semicircular, greatest diameter 2.54 (2.40-2.64) in eye length; fold on posterior margin rudimentary, broad-based. Gill openings almost upright; first four subequal in size, fifth longest, height of fifth slit 2.6 (2.23-2.52)% TL.

Mouth broad, upper jaw weakly concave, width 0.95 (0.99-1.06) in preoral length; postoral groove prominent, almost twice length of upper labial furrows, extending posterolaterally from angle of jaws. Teeth similar in upper and lower jaws; upper teeth unicuspid, interlocking, blade-like; cusps directed strongly laterally, low, base of tooth broader than length of cusp.

Nostrils large, suboval; anterior nasal flap length 5.2 (4.3-5.1)% TL, with greatly enlarged medial barbel; barbel extending past lower jaw (not quite reaching mouth in paratype AMS I 42891-001); posterior nasal flap large; internarial space 2.03 (1.88-2.06) in preoral length, 1.65 (1.70-2.06) times nostril length.

Dermal denticles on flank small, strongly imbricate; mainly tricuspidate. Crowns broad, directed posterolaterally, more elevated posteriorly than anteriorly; with pronounced median ridge (~1.0 mm in length); median ridge most strongly elevated anteriorly, originating forward of rest of crown, extending full length of crown; weak mesial furrow developing anteriorly on median ridge and converging towards posterior tip of crown; lateral cusps short and variable, usually with single short, blunt lateral cusps or two very short blunt cusplets; crowns lacking elevated ridges laterally.

First dorsal fin tall, slightly raked, bluntly pointed apically; base robust, fleshy; anterior margin weakly convex; posterior margin moderately concave, upper portion directed slightly posteroventrally from fin apex, point of deepest concavity near middle of margin; rear lobe of fin moderately deep basally, long; free rear tip sharply acute; inner margin of fin almost straight; insertion of fin base almost midway between pectoral-fin insertion and pelvic-fin origin; fin origin over pectoral-fin free rear tip; exposed spine base broad, 0.8 (0.9- 1.0)% TL, exposed anteriorly at about junction of spine and soft portion of fin; soft portion of fin connected at about a third of total spine length; spine tapering gradually distally (abraded apically in all types), anterior margin very weakly convex; exposed portion only slightly raked, subequal in length to exposed portion of second dorsal-fin spine; height of spine at apex much lower than soft portion of fin; pre-first dorsal length 3.34 (3.21-3.33) times in TL; first dorsal-fin length 1.70 (1.60-1.75) times its height, 1.05 (1.01-1.04) times second dorsal-fin length; first dorsal-fin height 1.07 (1.07-1.20) in second dorsal-fin height; exposed first dorsal spine length 0.61 (0.47-0.54) in height of fin.

Second dorsal fin large, raked; base very fleshy, much more thickened than first dorsal-fin base; anterior margin slightly convex, apex bluntly pointed; posterior margin strongly concave, maximum concavity about a third distance from free rear tip, upper portion almost straight, sloping very slightly anteroventrally from apex; free rear tip moderately elongate, acutely pointed; inner margin weakly convex, length 0.62 (0.56-0.69) times fin height; second dorsal-fin length 1.74 (1.70-1.91) times its height; spine length 0.63 (0.55-0.74) in height of fin; fin origin posterior to pelvic-fin insertion; origin of exposed dorsal spine posterior to free rear tip of pelvic fin; spine exposed near level of junction with soft portion of fin; exposed spine base broad, 0.9 (0.9- 1.0)% TL, spine tip when undamaged extending to about level of insertion of fin; soft portion and spine apices subequal in height (slightly shorter in paratype AMS I 42891-001); interdorsal ridge absent; interdorsal space 0.85 (0.86-0.91) in pre-pectoral length, 1.36 (1.40-1.53) in pre-first dorsal length.

Pectoral fin moderate in size, weakly falcate; anterior margin moderately convex; apex broadly pointed; posterior margin strongly concave; free rear tip broadly rounded; inner margin moderately convex, length 8.0 (7.1-7.9)% TL; base short, 2.95 (2.66-2.98) in length of anterior margin. Pelvic fins large, subtriangular; anterior margin weakly convex; posterior margin straight anteriorly with a subterminal notch (less apparent in paratypes); apex broadly rounded; free rear tip acute.

Caudal fin relatively long, broad lobed; upper caudal margin almost straight, tip bluntly pointed (similar to second dorsal-fin apex); preventral margin moderately convex, tip narrowly rounded; lower postventral margin short, almost upright, straight; caudal fork moderately concave; upper postventral margin strongly convex ventrally, with moderate concavity towards apex (less apparent in paratype AMS I 27022-001); dorsal caudal margin 0.91 (0.91-1.07) in head length; length of lower caudal lobe 1.61 (1.47-1.64) in upper lobe length.

Vertebral centra 115, monospondylous 50, precaudal 85 and caudal 30. Teeth (based on paratype AMS I 19154-001) in upper jaw 13+14=27, lower jaw 12+12=24.

Coloration. When fresh (based on holotype): dorsal surface of body uniformly medium greyish; ventral surface (from head to vent) mostly pale, with a few scattered darker blotches; nasal barbels almost uniformly pale; light and dark tonal areas most strongly demarcated on head, interface between them extending from snout to pectoral-fin base, passing well under eye through mid-gill slits. Dorsal fins mostly pale grey, with light and dark areas; upper posterior margin distinctly whitish, preceded by blackish submarginal bar, pattern extending from fin apex to point of maximum concavity; dark marginal streak extending from near first dorsal-fin apex to about insertion of exposed fin spine; additional white flecks on anterior margin of first dorsal fin in holotype (not apparent in paratypes); fin spines pale, greyish brown, most pronounced on anterior margins. Caudal fin mostly greyish; posterior margin with narrow white border, demarcated internally for its entire length by a blackish subterminal bar. In preservative (based on holotype): similar in coloration, but blackish markings on dorsal and caudal fins less apparent. Pectoral and pelvic fins on dorsal surfaces similar to upper body, but with narrow white posterior margins; ventral coloration slightly darker on posterior half of fin than on base.

Size. Types consist of four females between 713 and 1230 mm TL. Two New Zealand specimens reported by Garrick & Paul (1971), which may be conspecific with Cirrhigaleus australis , were females (922 and 1082 mm TL).

Distribution. Type specimens collected from the mid-continental slope off southeastern Australia between Sydney (ca. 33°S) and eastern Tasmania (ca. 42°S) in depths of 360-640 m. New Zealand specimens were collected from the Bay of Plenty, North Island, in depths of 360 and 440 m (Garrick & Paul, 1971).

Etymology. Derived from the Latin australis in reference to the distribution of this species in the temperate Southern Hemisphere.

Common name. We propose “Southern Mandarin Dogfish” in allusion to its well accepted genus group name and its southern distribution.

Discussion

The Mandarin sharks, Cirrhigaleus australis and C. barbifer , differ from their congener C. asper , in possessing anterior nasal flaps with greatly elongated, moustache-like barbels that reach to (or almost to) the mouth rather than nasal flaps with very broad and short barbels that fall well short of the mouth. Cirrhigaleus australis (Figs 1-4) can be distinguished from C. barbifer (Figs 5-8) in a number of morphometric characters: smaller eye (eye length 3.3-4.1 vs. 3.9-4.3% TL, 1.4-1.5 vs. 1.0-1.1 in horizontal preorbital length), longerbased and more falcate second dorsal fin (base length 9.8-10.0 vs. 7.7-9.1% TL; anterior margin 14.5-14.8 vs. 12.5-14.0% TL; height 7.5-8.7 vs. 8.8-9.6% TL, 1.7-1.9 vs. 1.4-1.6 in its total length), shorter dorsal spines (perpendicular height of first dorsal spine 7.6-8.0 vs. 8.3-10.4% TL; perpendicular height of second dorsal spine 7.5-8.5 vs. 9.5-10.6 TL; exposed second dorsal spine length 5.0-6.1 vs. 3.9-4.7 in pectoral -pelvic space), slightly shorter upper labial furrow (mouth width 7.1-9.1 vs. 6.0-6.7 times labial furrow length), and shorter prenasal snout (2.0-2.2 vs. 2.5-3.2 times horizontal prenasal length). Additional morphometric differences between C. australis and C. barbifer include: dorsal -caudal space 7.6-8.1 vs. 8.0-8.7% TL and pectoral posterior margin 12.3-13.0 vs. 10.6-11.8% TL. Vertebral counts for the two species were similar (precaudal centra 85-87 in C. australis vs. 84-86 in C. barbifer ; total centra 114-115 vs. 112-114).

Cirrhigaleus barbifer (Fig. 5) appears to have a more prominently humped nape than C. australis (Fig. 1) but this may be related to posture or preservation. They also differ in dorsal coloration with C. australis having a uniformly medium greyish colour compared to the darker brownish coloration of C. barbifer (see Fig. 5 and description by Herre, 1935). Cirrhigaleus australis differs from Indonesian specimens of C. barbifer in the structure of the CO1 gene (B. Ward, CSIRO, pers. comm.). The flank denticles of the holotype of C. australis are much smaller than in the similarly-sized Indonesian C. barbifer (crowns ~1.0 vs. 1.3 mm in length; Figs 4 and 7).

A single record from Vanuatu (Fourmanoir & Rivaton, 1979) of a 950 mm TL individual cannot be accurately identified, due to the lack of adequate photographs or illustrations, as either C. australis or C. barbifer . Thus, further specimens from this region are required to confirm the true species involved.

Ontogenetic differences in morphometrics were observed between the smallest paratype (713 mm TL, AMS I 19154-001) and the three larger types (970-1230 mm TL). These include: prebranchial length 17.3 vs. 15.7-16.4% TL; prepelvic length 51.8 vs. 54.1-54.6% TL; pectoral -pelvic space 28.1 vs. 29.6-31.3% TL; pelvic -caudal space 17.5 vs. 18.7-19.0% TL; interorbital space 9.4 vs. 7.6-8.1% TL; eye length 4.1 vs. 3.3- 3.8% TL and exposed second dorsal spine length 4.6 vs. 5.2-6.0% TL.

An Indonesian specimen of C. barbifer (CSIRO H 5875-09) differed from the Japanese specimens in some characters: exposed first dorsal spine length 8.0 vs. 5.0% TL, and distance from midpoint of first dorsal fin to pectoral-fin insertion 8.6 vs. 11.9-12.3% TL. Additional material and research is needed to test the conspecificity of Indonesian and Japanese populations.