Lethrinus ornatus Valenciennes

Wilson, G. G., 1998, A description of the early juvenile colour patterns of eleven Lethrinus species (Pisces: Lethrinidae) from the Great Barrier Reef, Australia, Records of the Australian Museum 50 (1), pp. 55-83 : 78

Lethrinus ornatus Valenciennes

PI. 3C

Material examined. (11 specimens: 20-91 mm). AUSTRALIA Great Barrier Reef region , AMS 1.34917 - 001 (1: 32 mm), AMS 1.34932 - 001 (1: 36 mm), not retained (6:20-69) ; INDONESIA Maumere Bay (Flores), not retained (2: 20 mm) ; SOLOMON ISLANDS New Georgia Island , AMS 1.22128 - 154 (1: 91 mm) .

Diagnosis. Body relatively deep, its depth 2.5-2.8 in SL; 5.5 dorsal scale rows, 15 ventral scale rows; maxillary serrations 2-4 at 20 mm, absent at greater than 28 mm; dorsal spine 5 the longest at 20-60 mm (rarely 4 at greater than 50 mm).

Diagnostic colour notes. Primary stripes 4, bright orange, of similarwidth and intensity, interspaces silvery off-white;

fins hyaline, pink to pale scarlet distally; pale scarlet band along rear margin of operculum at greater than 28 mm; dark markings seldom displayed.

Colour notes. A striking species with few differences in colouration between adults and juveniles, difficult to confuse with other Lethrinus species. At 20-80 mm ( PI. 3A): dorsum and nape pale grey-tan, flank silvery offwhite, belly off-white; 4 prominent bright orange primary stripes, of similar width and intensity, fine grey borders, interspaces grey-tan or silvery off-white, dorsal stripe extending to below medial dorsal rays, remaining stripes terminating at base of caudal peduncle; black banding and cuboidal shoulder blotch seldom displayed infield although common at capture ( PI. 3C) and after death, rapidly switched on or off, 6-7 bands along dorsum, most connecting with further banding between lateral-line and belly, 2-3 similar bands along caudal peduncle; dark midlateral stripe occasionally displayed in field, dark grey, width approximately 4.0 in body depth, obscuring dorsal and orbital stripes, pectoral and ventral stripes usually remaining visible though dulled; head similar to body, snout yellow-brown, cheek silvery off-white, may have diffuse tan blotch, eye often bisected by near-vertical black band in field, pale scarlet band developing along rear margin of operculum from 28 mm (faded in PI. 3C); fins mostly hyaline, caudal and pectoral fins pale pinkish yellow, anterior half of spinous fins off-white with dark grey patches basally, deep pink to scarlet distally in field, diffuse pink at capture (as in PI. 3C) and when freshly-killed.

At greater than 80 mm, body, head and fins as in smaller specimens, dark mid-lateral stripe and banding absent.

Colour in alcohol. Dorsum pale grey-tan with 5-6 dark bands; ventral half of body and primary stripes faded to off-white, dark banding below lateral-line dissected by primary stripes into 3-6 series of square blotches; banding retained along caudal peduncle; fins hyaline.

Ecology. Uncommon at Green Island, settles at 19-21 mm into shallow reef seagrass habitats, remaining there until 70-80 mm; solitary, not appearing site attached, seldom in close association with other fishes, occasionally joining small loose schools with juvenile Stethojulis strigiventor, Siganusjuscescens , Parupeneus indicus and congeners of a similar size, particularly in the presence of piscivorous carangids or lutjanids; at 40-70 mm periodically resting briefly at the base of the seagrass canopy in tall-dense Cymodocea and Halodule , fleeing over the canopy when disturbed.

Field identification. Juvenile L. ornatus are best distinguished in the field by their deep body profile, intense orange primary stripes and rarity of conspicuous dark banding or mid-lateral stripe patterns (cf. frequent displays in other species with bright primary stripes). Recentlysettled specimens display near-identical colouration to later stages, although less conspicuously.