Choerodon sugillatum Gomon, 1987

Martin F., Martin F., 2017, A review of the tuskfishes, genus Choerodon (Labridae, Perciformes), with descriptions of three new species, Memoirs of Museum Victoria 76, pp. 1-111 : 85-87

Choerodon sugillatum Gomon, 1987

Wedgetail Tuskfish

Choerodon sugillatum Gomon, 1987: 19 , Queensland, Cape

Bedford ( Australia), 15° 13.59'– 15° 15.00'S , 145° 23.36'– 145° 27.87'E.

Diagnosis. Dorsal fin rays XII, 8; anal fin rays III, 10; pectoral fin rays ii, 13, rarely 14, dorsalmost ray short 2.8–11.7% pectoral fin length, ventralmost ray distinctly longer than those immediately above, posterior edge of fin falcate, dorsoposterior corner bluntly pointed, posteroventral corner sharply pointed; body shallow, 29.3–37.7% SL, head depth 21.5–29.2% SL, caudal peduncle depth 10.0–12.8% SL; head blunt, dorsal profile of snout moderately steeply curved, snout length 8.0– 10.6% SL; predorsal scales approximately 6 or 7, reaching forward on dorsal midline to midpoint between posterior extent of eye and posterior edge of preopercle; cheek with small partially embedded scales in about 6 diagonal rows, posteriormost with about 6 or 7 scales to upper extent of free preopercular edge, reaching forward to corner of upper lip crease above mouth, with very broad naked margin posteriorly and ventrally on preopercle; 2 rows of about 5–9 small scales (only 1 or 2 scales in second row when present) on subopercle adjacent preopercular edge extending forward to about anterior end of ventral preopercular margin; each lateral line scale usually with unbranched laterosensory canal tube; scales above lateral line about 2½ or 3; cephalic sensory canal pores moderately numerous confined to lines or short branches associated with major canals; second pair of canines in lower jaw directed dorsolaterally; dorsal and anal fins without basal sheath, 1–3 progressively smaller accessory scales adjacent to fin base; posterior lobe of dorsal and anal fins not quite reaching hypural crease; caudal fin truncate, posterior margin convex medially in adults, upper and lower corners pointed; pelvic fin not quite reaching anus, length 17.3–21.3% SL. (See Table 5 for additional meristic and morphometric ranges.) Olive above, white below with blue-edged black bar below lateral line under 3rd or 4th dorsal fin spine; blue lines anteroventral from eye, below and above eye and across pectoral fin base; caudal fin with darker, posteriorly tapering wedge-shaped patch centrally.

Reaches moderately small maximum size, largest specimen examined 149 mm SL.

Pigmentation in alcohol. Juveniles pale with dusky scale margins dorsally and prominent dusky stripe above lateral midline from opercular margin to distal caudal fin margin; darker mark on stripe below bases of second and third dorsal fin spines; centre of posterior caudal fin margin with small dark blotch; fins otherwise hyaline.Adults pale, slightly dusky dorsally, with prominent dark slash preceded by immaculate pale slash above and slightly behind pectoral fin base; narrow dark margin wrapping around dorsal edge of pectoral fin base; fins pale except for dark mark at centre of caudal fin’s posterior margin.

Fresh colours. Juveniles generally similar to initial phase adults as described below with additional brown blotches dorsally; fins mostly transparent with 2 olive stripes in dorsal fin and 2 blue stripes in anal fin ( Kuiter, 2010: 56, top B & C).

Initial phase adults olive dorsally, white ventrally with narrow orange to brown stripe just above lateral midline from snout to base of tail, stripe broader with blue dorsal edge on head (fig. 45); scale centres blue, at least posteriorly, yellow streaks between scale rows on caudal peduncle; distinctive vertical black mark with blue anterior margin on midlateral stripe above and slightly behind pectoral fin base; 2 yellow edged blue lines directed anteroventrally from eye to upper jaw, 2 others crossing snout in front of eye, short blue line directed posteriorly from top and bottom of eye, lower line curving ventrally anteroventral to eye and continuing onto chin; blue stripe directed posteriorly from lower jaw to posterior edge of preopercle; lower lip blue; broad blue band with narrow yellow margins crossing pectoral fin base. Dorsal and anal fins blue, dorsal fin with thin yellow horizontal line proximally and distally; anal fin with thin yellow horizontal lines proximally and midlaterally; caudal fin blue with posteriorly converging yellow lines, lines edged with black posteriorly at centre of rear margin of fin. Pectoral and pelvic fins hyaline; pelvic fin with lengthwise yellow submarginal line near leading edge ( Sainsbury & Kailola, 1984: 261, middle as Choerodon sp 2 .).

Terminal phase adults similar to initial phase but pinker overall with narrower midlateral stripe and vertical blue line or spots on most scales on side. ( Allen, 1985: fig 334, as Choerodon species; Kuiter, 2010: 56, top A)

Etymology. The name sugillatum is Latin for “black and blue”, a reference to the characteristic marking on the side of this species.

Distribution. Restricted to northern Australia, extending at least from Cape Tribulation, Queensland to the Monte Bello Islands, Western Australia (fig. 46). Occurs on open sand with sparse algal cover, like Caulerpa , at depths of 10–120 m ( Kuiter, 2010: 56).

Comments. Described from a series of specimens from both coasts of northern Australia ( Gomon and Allen, 1987: 19, NMV A 3126, 104 mm SL, holotype), C. sugillatum frequently features in the bycatch of northern Australian prawn fisheries. As a dark slash-like marking is present on the side above the lateral line in a number of species of this subgenus and at least one other apparently unrelated subgenus, it cannot be relied on alone for recognising this species. However, in combination with the crescentic pectoral fin, having a nub-like first fin ray, the features alone distinguish the species .

Material examined. 114 specimens, 35.3–149 mm SL; see appendix .