Ontogenetic development of caudal skeletons in Trachinotus ovatus larvae

We investigated the skeletal ontogeny of Trachinotus ovatus larvaeof 1~18 dph by using double staining technique. Results indicate that: on 18 dph, the caudal skeletons of T.ovatus consisted of hypurals (Hy), epurals (Ep), parhyurals (Phy) and uroneural (Urn) near the urostyle. On 7 dph, the first hypural (Hy1) appeared in the caudal area (CA). Hy1, Hy2 and Phy appearedat the end of urostyle on 9 dph. On 9~15 dph, with the appearance of Hy3 and Hy4, ossification approached to CA, and modified haemal spines (Mhs) and modified neural spines (Mns) appeared simultaneously. On 15 dph, the Eps of fish fully developed. On 15~18 dph, Hy5 formed next to Hy4, and the outline of each skeleton becomed observable. This study explored the morphological characteristics of caudal skeletal ontogeny in larval T.ovatus, which provides fundamental information for future researches on skeletal development of T.ovatus and other similar species.