by KAMOLRAT PHUTTHARAKSA SIGANIDAE by KAMOLRAT PHUTTHARAKSA

Siganids are small to moderate size, primarily herbivorous fishes found in a variety of habitats including coral reefs, sea grass beds and estuaries. Some species have commercial value as a food fish, and some have been considered for aquaculture. RABBITFISHES

Review of Morphological features General appearance Larvae are initially elongate, but become moderate in depth before flexion. They are laterally compressed, and have 22-24 myomeres. The head is initially moderate in size and round, and the snout is blunt; by flexion. The eye is large in preflexion larvae but moderate to large following flexion.

Head spination Pigmentation Larvae develop spines along both preopercular borders: these remain small to moderate. Serrate ridges form shortly thereafter along top of the head and leterally on the snout. During and following flexion small spines or serrate ridges from on the supraocular, pterotic, posettemporal, suparcleithrum, angular, infraorbital and lateral etmoid. Pigmentation Larvae have pigment on the dorsal surface of the gut and along the ventral midline of the tail. The number of malanophores in the series decreases with development until flexion.

Meristic Character D A P1 P2 C Vertebrae Siganus XIII-XIV, 10 VII, 9-10 15-19 I, 3, I 9+8 10+14=24

Family: Siganidae Genus: Siganus Sampling Location: Gulf of Thailand & Palavan Sampling Gear: Bongo net Stage: Flexion (Gulf of Thailand) Postflexion (Palavan)

Measurements Stage BL HL ED SnL PAL BD Flexion 5.0 1.5 0.6 0.3 2.4 1.8 (mm) Stage BL HL ED SnL PAL BD Flexion 5.0 1.5 0.6 0.3 2.4 1.8 Postflexion 10.0 3.1 1.2 0.9 4.7 3.4

Counts Stage D A P1 P2 C Flexion IIII - I 23 Postflexion I,3,I * Myomeres Flexion IIII - I 23 Postflexion XIV, 10 VII, 9 15 I,3,I * * C: 9+8 (Leis and Carson-Ewart, 2000) The body depth moderate 30%BL, gut coiled and compact early, anus open 50 %BL.

Flexion The body depth moderate 30%BL, gut coiled and compact early. Larvae have supraoccipital and frontal, serrate ridges form shortly thereafter along the top of the head, supracleithral, and laterally on the nasal, and both preopercular Larvae have serrate ridges anterior pelvic girdle. Dorsal fin are 5 spine, anterior of the second spine of dorsal and spine of pelvic fin have serrate.

Flexion Dorsal and anal fin still undeveloped, Caudal fin appear soft rays Pigment appear on the brain and the head, on gut, membrane of dorsal fin and pelvic fin, and anal fin base.

Flexion Postflexion