Choerodon, Bleeker, 1847

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 : 58-59

Choerodon (Lutjanilabrus nsubgen.)

Table 2

Diagnosis. Dorsal fin rays XIII, 7; anal fin rays III, 10; pectoral fin rays ii, 14, rarely 15, dorsalmost ray of moderate length 25.5–41.7% pectoral fin length, ventralmost rays shorter than those above, posterior edge of fin obliquely straight, dorsoposterior corner bluntly pointed, posteroventral corner angular to broadly rounded; body moderately deep, 29.8–39.6% SL, caudal peduncle depth 12.0–14.9% SL, head depth 22.2– 31.8% SL; head broadly pointed, dorsal profile of snout oblique, snout length 10.9–15.3% SL; predorsal scales approximately 12–15, reaching forward on dorsal midline to or almost to above middle of eye; cheek with small partially embedded scales in about 8 diagonal rows, posteriormost with about 12 or 13 scales to upper extent of free preopercular edge, reaching forward almost to corner of upper lip crease above mouth, with broad naked margin posteriorly and ventrally on preopercle; about 2 rows of 10–12 small scales (2–4 scales in second row dorsally) on subopercle adjacent preopercular edge extending forward nearly to anterior end of ventral preopercular margin; each lateral line scale with multiple branching laterosensory canal tube; scales above lateral line about 4 or 5; few cephalic sensory canal pores confined to lines or short branches associated with major canals; second pair of canines in lower jaw directed dorsolaterally and curved posteriorly; dorsal and anal fins with very low basal sheath comprising 1 or 2 slightly smaller accessory scales at deepest; posterior lobe of dorsal and anal fins not reaching hypural crease; caudal fin truncate to slightly rounded. (See Table 2 for additional meristic and morphometric ranges.) Distinctive colouration with white head and body and prominent brown to black midlateral stripe from eye to base of tail at all sizes, although less distinct in largest individuals; smaller individuals with darkened circular to elongate spot superimposed on stripe on rear half of caudal peduncle.

Etymology. The group name Lutjanilabrus nsubgen is from the Malayan ikan lutjang, a vernacular for members of the snapper genus Lutjanus and labrus, apparently a Greek vernacular for wrasse, in reference to the snapper-like form of this monotypic subgenus of labrid.

Comments. Kuiter (2010: 62) placed Choerodon vitta in a separate unnamed subgenus based on its “unusual form, superficially like some members of Lutjanidae ”. The species was found by Puckridge et al. (2015: 67, fig. 1) to be a sister species of Choerodon fasciatus based on genetic evidence. These two species differ considerably from each other in overall form, dorsal and pectoral fin counts, caudal fin form, colouration and apparent habitat preference.

The body form of the sole representative of this subgenus (fig. 1, clade 4b) is far more symmetrical with a distinctly pointed head than in species of other subgenera, apart from the dwarf members of the subgenus Peaolopesia , which have a more slender appearance and blunter head.