Lethrinus genivittatus Valenciennes
Creators: name: Wilson, G. G.
Publisher: name: Zenodo
Year: 1998
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Actinopterygii
Perciformes
Lethrinidae
Lethrinus
Lethrinus genivittatus

description: <i>Lethrinus genivittatus</i> Valenciennes PI. 1E,F,G, Figs 3A, 5A, 8, 9 Material examined. (38 specimens: 17-99 mm). AUSTRALIA New South Wales, AMS I.17458-004 (1: 32 mm), AMS 1.26438 - 003 (4: 17-34 mm), AMS 1.30814 - 007 (1: 25 mm); Great Barrier Reef region, AMS 1.20786 - 012 (3: 18-23 mm), AMS 1.32476 - 003 (2: 18- 19 mm), AMS 1.34911 - 002 (7: 20-26 mm), AMS I.34911-003 (1: 39 mm), AMS I.34911-004 (1: 25 mm), AMS 1.34915 - 001 (2: 18-21 mm), AMS 1.34916 - 001 (1: 19 mm), AMS 1.34917 - 001 (1: 31 mm), AMS I.34917- 002 (1: 19 mm), AMS 1.34919 - 001 (1: 30 mm), AMS (I.33287-001) (1: 20 mm), USNM 336681 (6: 21-32 mm); Queensland south of Great Barrier Reef, AMS IB.1023 (4: 46-70 mm), AMS E.1359 (1: 99 mm). Diagnosis. Body depth variable, 2.6-3.8 in SL, deepening with increased SL; 4.5 dorsal scale rows, 15 (rarely 16) ventral scale rows; maxillary serrations 5-7 (occasionally 4) at 16-40 mm, fewer at greater than 40 mm, absent by 80-90 mm; cheek scales retained until 25-27 mm; dorsal spine 2 relatively elongate, its length:2: dorsal spine 3 at greater than 30-35 mm (occasionally 25-30 mm). Diagnostic colour notes. Dorsum yellow-tan, 4-6 distinct narrow black bands extending to lateral-line, body offwhite tan to silver ventrally; intense cuboidal shoulder blotch, surrounded by silvery halo (PI. IF), pointed tip crossing lateral-line (Fig. 5A); 3-4 orange stripes below lateral-line, of equal intensity and width, interspaces silver; at greater than 35 mm, 3 broad tan bands on suborbit and preoperculum (PI. IG); fins hyaline. Pre-settlement colour notes. Pre-settlement pigmentation variable with SL (16-21 mm), complete by 22 mm (Fig. 9): dorsum and flank translucent off-white to pale tan, belly and cheek silver; prior to appearance of melanophores, pigmentation restricted to yellow-orange xanthophores along myosepta and horizontal septum, sparse melanophores first appear over caudal peduncle and 1-3 scales below dorsal spines 4-5 forming early shoulder blotch (Fig. 9A), later increasing to 4-6 scales; 3-4 cuboidal blotches appearing between lateral-line and horizontal septum, behind shoulder blotch (Fig. 9B), followed by banding along dorsum and 2-3 indistinct blotches below horizontal septum (Fig. 9C), interspaces silver to pale blue; head with few markings, melanophores scattered over brain, dark band forming between orbit and maxilla; fins mostly hyaline, sparse melanophores and underlying xanthophores visible along spines. Colour notes. A distinctive species with few ontogenetic changes in juvenile colouration, capable of rapid pattern changes within 1-3 seconds. At 20-30 mm: snout and dorsum intense yellow-tan, head and body abruptly silvery off-white ventrally, lateral-line cryptic; 4 narrow primary stripes along flank, of similar widths, terminating near base of caudal peduncle, golden orange in captivity or when freshly killed (PI. lE), orange (rarely orange-tan) in field with dorsal stripe concealed by 3-4 pale brown to grey blotches (PI. 1F,G), interspaces silver (rarely pale blue, PI. IF); intense banding frequently displayed in field with concomitant partial-fading of primary stripes (Fig. 3A), dulled in captivity and after death (cf. PI. lE and IG), 4- 6 narrow bands along dorsum, series of blotches along ventral margin of lateral-line, further banding between blotches and belly (PI. 1G); blotch below dorsal spines forming diagnostic shoulder blotch (Fig. 5A), cuboidal with pointed tip extending over lateral-line and surrounded by silvery halo (PI. IF); intense dark mid-lateral stripe prevalent in field, width approximately 5.0 in body depth, rarely accompanied by banding or primary stripes; snout and cheek without darkmarkings, intermittent near-vertical black band bisecting eye in field; fins mostly hyaline, dorsal fin often similar hue to dorsum in field, sparse offwhite and dark patches over anterior half of spinous fins. At 20-30 mm, individuals in field frequently display background and primary-stripe colourations either with distinct shoulder blotch alone or without dark markings (as in PI. 6, p. 173 in Masuda &amp; Kobayashi [1994]). At 30-80 mm: mostly as in smaller individuals, dorsum greyish tan, banding more intense than when smaller, shoulder blotch and orange primary stripes prominent; two vertical dark tan bands visible on suborbital at greater than 35 mm (Fig. 3A, PI. 1G), third similar band along rear margin of preoperculum. Colour in alcohol.At 16-21 mm, late pre-settlement: body translucent off-white to pale straw, xanthophore pigmentation lost, melanophores retained in similar patterns to when freshly killed, fins hyaline. At greater than 20 mm, post-settlement: body and head pale greytan, belly off-white; dorsal banding slightly dulled, dark blotches below lateral-line indistinct; shoulder blotch faded from when freshly killed, halo absent; primary stripes lost; fins hyaline. Ecology. At less than 90 mm, common in dense shallow seagrass beds on coral reefs and in coastal embayments (0.2-3.0 m; <i>Cymodoeea, Halodule, Halophila, Thalassia, Zostera);</i> settlers recorded from 16 mm although typically 19-22 mm, mostly solitary, individuals 20-30 mm hover over the seagrass canopy, periodically picking food items off seagrass blades, occasional aggression noted towards conspecifics and congeners of a similar size; not appearing site-attached although seldom moving further than 1 m when disturbed, at less than 30 mm willrapidly seek shelter at base of canopy if closely approached; at greater than 30 mm occasionally joining loose multi-species schools with <i>Searus</i> species (Scaridae), <i>Parupeneus indieus, Siganus fuseeseens</i> and congeners of a similar size. Field identification. Although distinctive when freshly killed, may be easily confused with <i>L. obsoletus</i> under field conditions, particularly at less than 40 mm. Both species are capable of rapid changes in their overlying dark colour patterns and display 3-4 coloured primary stripes. When recently-settled (18-25 mm), <i>L. genivittatus</i> and <i>L. obsoletus</i> often display an almost uniform yellow-tan to grey-tan hue, and observation for several minutes is necessary before other patterns can be discerned. The shoulder blotch's form is useful for distinguishing these species (Fig. 5.): the <i>L. obsoletus</i> shoulder blotch is mostly vertically-rectangular, does not cross the lateral-line and is seldom surrounded by a pale halo. This contrasts with the square shoulder blotch with pointed extension over the lateral-line and pale halo in <i>L. genivittatus.</i> At less than 40 mm, dorsal bands tend to be narrower and of sharper definition in <i>L. genivittatus</i> than <i>L. obsoletus</i> (cf. PI. 1G and 2E). In many cases, it may be necessary to collect smaller specimens for confirmation with morphological characters or freshly-killed colour patterns. Identification notes. Carpenter &amp; AlIen (1989) report the degree of outward-curvature of the lower canine teeth, along with the greater length of the second dorsal spine over the third, to be the most useful means for separating <i>L. genivittatus</i> from other lethrinids. However, dentition is of little value for distinguishing <i>L. genivittatus</i> at less than 80 mm. Although the second dorsal spine is shorter than the third until 30-35 mm in most cases ("Diagnosis" above), it is still relatively elongate in individuals greater than 23 mm in comparison with other <i>Lethrinus</i> species, and may be a useful diagnostic character. The number of scale rows above the lateral-line also differentiates <i>L. genivittatus</i> (4.5) from similar species such as <i>L. obsoletus (5.5).</i> Previous descriptions. Early life history stages of <i>L. genivittatus</i> have been described and/or figured in several works. The larval development of laboratory-reared individuals 2.7-16.4 mm was described and figured (as <i>L. nemataeanthus)</i> by Mori (1988), although few details of pigmentation were given. Juvenile colour plates were provided by Kuiter (1993, length not given), Masuda &amp; Kobayashi (1994, 35 mm total length) and Kuiter &amp; Debelius (1994, 40 mm, reproduced here in PI. 1G). Sato (1984) noted the prolonged occurrence of maxillary serrations in <i>L. genivittatus</i> juveniles (under <i>L. nemataeanthus)</i> as "maxillary ornamented with row of tubercles in younger individuals".
description: Published as part of <i>Wilson, G. G., 1998, A description of the early juvenile colour patterns of eleven Lethrinus species (Pisces: Lethrinidae) from the Great Barrier Reef, Australia, pp. 55-83 in Records of the Australian Museum 50 (1)</i> on pages 69-71, DOI: 10.3853/j.0067-1975.50.1998.1274, http://zenodo.org/record/4652850
description: {"references": ["Masuda, H., &amp; Y. Kobayashi, 1994. Grand Atlas of Fish Life Modes. Tokai University Press, Tokyo, pp. 465.", "Carpenter, KE., &amp; G. R. AlIen, 1989. FAO species catalogue: Vol. 9. Emperor fishes and large-eye breams of the world (family Lethrinidae). An annotated and illustrated catalogue of lethrinid species known to date. FAO Fisheries Synopsis No. 125, Volume 9. FAO, Rome, pp. v + 118.", "Mori, K, 1988. Lethrinidae. Pp. 536 - 541. In M. Okiyama (ed.). An Atlas of the Early Stage Fishes in Japan. Tokai University Press, Japan. (in Japanese)", "Kuiter, R. H., 1993. Coastal fishes of South-eastern Australia. Crawford House Press, Bathurst, Australia, pp. xxi + 437.", "Kuiter, R. H., &amp; H. Debelius, 1994. Southeast Asia tropical fish guide. IKAN-Unterwasserarchiv, Frankfurt, Germany, pp. 321.", "Sato, T., 1984. Lethrinidae. Pp. 178 - 181. In H. Masuda, K Amaoka, C. Araga, T. Uyeno &amp; T. Yoshino (eds.). The Fishes of the Japanese Archipelago. Tokai University Press, Tokyo."]}