Choerodon albofasciatus, Martin F., 2017

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 : 64-68

Choerodon albofasciatus nom. nov.

Ira-modoki, Whitestripe Tuskfish

Choerodonoides japonicus Kamohara , l958: 2, pl. 1, fig. 1, Mimase Market, Kochi City ( Japan), junior homonym of Labrus japonicus Valenciennes (= C. azurio ).

Peaolopesia gymnogenys (not Günther). — Masuda et al., 1975:

294; Masuda et al., 1984: 202, Okamura and Amaoka, 1997: 519;

Nakabo, 2000: 969. Choerodon gymnogenys (not Günther). — Shen, 1993: 452; Chen,

2010: 384. Choerodon japoncus . — Kuiter, 2010: 63; Nakabo, 2013: 1088. Choerodon cf margaritiferus . — White et al., 2013: 265;

Puckridge et al., 2015: 65, 66, figs 1 & 2.

Diagnosis. Dorsal fin rays XII, 8 (rarely XI, 9); anal fin rays III, 10 (rarely 8); pectoral fin rays ii, 13 (rarely 12), dorsalmost ray short 7.2–13.1% 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, 27.8– 32.5% SL, head depth 21.2–25.5% SL, caudal peduncle depth 10.8–11.6% SL; head blunt, dorsal profile of snout steep, snout length 9.9–13.1% SL; predorsal scales approximately 7, reaching forward on dorsal midline to or just in advance of posterior edge of preopercle; cheek with small partially embedded scales in about 4 or 5 diagonal rows, posteriormost with about 8–10 scales to upper extent of free preopercular edge, reaching forward almost to corner of upper lip crease above mouth, with very broad naked margin posteriorly and ventrally on preopercle; row of about 8–10 small scales on subopercle adjacent preopercular edge extending forward to about anterior end of ventral preopercular margin; each lateral line scale with unbranched laterosensory canal tube; cephalic sensory canal pores moderately numerous confined to lines or short branches associated with major canals; scales above lateral line about 2½ or 3; second pair of canines in lower jaw directed laterally, recurved posteriorly; dorsal and anal fins without basal sheath, additional small scale at top of some oblique rows; posterior lobe of dorsal and anal fins reaching well short of hypural crease; caudal fin truncate, with posterior margin slightly convex medially, upper and lower corners slightly pointed; pelvic fin reaching to anus, length 21.4–24.8% SL. (See Table 5 for additional meristic and morphometric ranges.) Red to green above, white below with with pearly blue midlateral stripe angled from underside of eye to base of caudal fin, stripe deflected downward to upper jaw below front of eye; terminal phase with second narrower stripe from back of eye along lateral line to top of caudal peduncle; scales posteroventrally with vertical pearly blue line.

Reaches moderately small maximum size, largest specimen examined 152 mm SL.

Pigmentation in alcohol. Juveniles unknown. Adults pale with moderately narrow tapering dark stripe directed posteriorly and slightly dorsally from centre of posterior margin of orbit towards posterior end of dorsal fin base, terminating slightly below last few rays; similar stripe directed from lower extent of orbit to just above centre of caudal fin base; space between stripes dark dusky tapering to point adjacent termination of ventral stripe; fins pale.

Fresh colours. Juveniles unknown. Initial phase adults reddish orange above, white below, with broad white stripe running from tip of snout under eye and angled slightly dorsally to caudal fin base above lateral midline, stripe with distinct red margin from lower edge of eye to caudal base dorsally and from opercle to caudal base ventrally (fig. 33A); scales below stripe on sides blotched with red to level of lower end of pectoral fin base; head with white cheeks and red lips. Dorsal fin yellow with hyaline submarginal stripe; anal fin hyaline with broad yellow midlateral stripe; caudal fin mostly yellow. Pectoral and pelvic fins hyaline; pelvic fin with lengthwise yellow submarginal line near leading edge ( Masuda et al., 1984: pl. 193, fig. B; Okamura & Amaoka, 1997: 519, fig. 1, as Paeolopesia gymnogenys ; White et al., 2013: 265, fig. 89.14, as Choerodon cf. margaritiferus ).

Terminal phase adults green above, yellow reticulation midlaterally and white ventrally, each scale on side with vertical pearly line (fig. 33B); broad pale blue stripe from lower margin of eye above pectoral fin base to just above centre of caudal fin base; second narrower blue stripe from posterior margin of eye curving ventrally to join first below middle of soft portion of dorsal fin; head with yellow stripe from upper jaw to anteroventral margin of eye; second curving from posterior end of upper jaw across operculum and along pectoral fin base; space between yellow stripes pale blue. Dorsal fin pale pinkish brown with narrow yellow submarginal stripe; anal fin white with narrow yellow medial stripe; caudal fin blue basally, posterior half red. Pectoral fin red; pelvic fin white with lengthwise yellow submarginal line near leading edge ( Masuda et al., 1984: pl. 193, fig. A; Shen, 1993: pl. 144, fig. 3, as C. gymnogenys ; Chen et al., 2010: 384, fig. C).

Etymology. The name albofasciata is from the Latin albo for “white” and fasciatus meaning “envelope with bands”, in reference to the prominent white stripe on the side as part of the initial phase colouration of this species.

Distribution. Occurs along the western edge of the Pacific from Inami, on the south-eastern coast of Honshu Island in Japan to Shark Bay, Western Australia (fig. 34) at depths of at least 95– 120 m.

Comments. Kamohara’s Choerodonoides japonicus (l958: 2, pl. 1, fig. 1) is clearly a species of Choerodon ( Gomon, 1997: 812) and therefore a junior homonym of Labrus japonicus Valenciennes , in Cuvier & Valenciennes, 1839 (= Choeodon japonicus ), itself a homonym of Labrus japonicus Houttuyn, 1782 . The species therefore requires a new name and C. albofasciatus is proposed as a replacement.

The species has been treated variously in the literature, as cited in the synonomy above, and therefore confused with C. gymnogenys and C. margaritiferus , with which it shares the white to pearly lateral stripe or pair of stripes. The same basic pattern occurs in C. gomoni as well as C. auruilentus described below. Choerodon albofasciatus differs from all four in having its cheek scales extending forward to the anterior end of the exposed ventral edge of the preopercle versus to or less than to the middle of the preopercular edge.

Material examined. 11 specimens, 96.7–152 mm SL; see appendix.