Morphological and identification of fish larvae (Acanthuridae, Gempylidae and Trichiuridae )
from Southeast Asia waters
by
Kosum polrong
Review to morphological features
AcanthuridaeBody 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)
a = present studyB = from review
Size(mm) D A P1 P2 C M
- (b) IV-XI, 19-33
II-III, 18-32
14-19
I, 3-5
8+8 21-23
5.30 (a) V, 29 II, 30 16 I, 0 8+8 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(SnL) = 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.
5.3mm.(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.