Morphological and identification of fish larvae Acanthuridae Gempylidae

Morphological and identification of fish larvae )Acanthuridae, Gempylidae and Trichiuridae ( from Southeast Asia waters by Kosum polrong

Review to morphological features Acanthuridae Body shape : Pre flexion-body is moderate deep, strongly compressed laterally, they have 21 -23 myomeres and the gut coiled. Flexion-deeper more than of body, snout have a triangular head and the mouth is small. The eyes a round and moderate to large size.

Spination : Pre flexion-the smaller spines is early appearance in larvae 1. 8 mm have a bones such as supraoccipital crest serrate, preopercle, lower jaw, mid-ventral keel and pelvic girdle. Flexion-following presented of spines at the supracleithral, posttemporal, opercular serrate

Pigmentation Preflexion-The larvae pigment present on brain, gut, along throat, lower jaw, and dorsal surface of gas bladder. Flexion-In some species. The pigment occurrence on caudal peduncle and increase to heavy and density in late stage.

Similar families and genus Difference of characters - Zanclids not have large anal fin spine, the elongate of third dorsal fin spine and in preflxion stage have a longer than of preanal length. - Menids lack elongate fin spine and serrate crests or ridges of head. - siganids and leiogngsthids have larger than preopercular spines and sometime of myomeres number more than to 24

Table 1 Meristic characters larval of Acanthuridae )Ahlstrom, 1948; Leis and carson, 2000; Richards, 2006; Chayakul, 2007) Size(mm) - (b) 5. 30 (a) D A IV-XI, 1933 II-III, 1832 V, 29 II, 30 a = present study B = from review P 1 P 2 C 14 - I, 3 -5 8+8 19 16 I, 0 8+8 M 21 -23 22

Specimens data Participant : Mr. Pitoon puewkhao Family : Acanthuridae Generic name : Naso sp. Sampling locality : Andaman sea Sampling gear : Bongo net Stage: Flexion

Measurements of data - Body length(BL) = 5. 30 mm. - Head length(HL) = 2. 20 mm. - Eye diameter(ED) = 0. 50 mm. - Snout length(Sn. L) = 1. 20 mm. - Preanal length(PAL) = 1. 93 mm. - Body depth(BD) = 4. 20 mm.

Figure A. Naso sp. 2. 20 mm. (Leis and carson, 2000) Figure B. Naso sp. 3. 80 mm. (Leis and carson, 2000)

Figure 1 Naso sp. 5. 3 mm. (BL) 40 x

Morphological features Body shape : - Very deep(79. 26%) - Large head(41. 51%) - Small eye(22. 73%) Gut : - Coiled Head spination - Supraocipital crests and spraocular

Pigmentation The pigment present on brain, around of abdominal cavity, pectoral fin base and caudal peduncle. All pigment increase to heavy and density in late stage.