Vol. 40 No. 4, 2001

Early Osteological Development of the Yellow Tail Seriola dumerili (Pisces: Carangidae)

Chen-Hsiang Liu

Department of Fishery Information, Fisheries Research Institute, Council of Agriculture, Keelung, Taiwan 20220

Chen-Hsiang Liu (2001) The osteological development of Seriola dumerili was studied in a series of 15 cleared-and-stained specimens (6.6-32 mm).  The dorsal spine began to ossify by 12.7 mm, and its soft rays by 27.2 mm, and all elements (VII-I, 32) were completed by 23.5 mm. Ossification of dorsal pterygiophores occurred initially by 15.9 mm.  Anal fin ray formation (II-I, 20) was completed by 12.7 mm, and soft rays began to ossify at 24.5 mm. Ossification of the anal pterygiophores occurred initially by 15.9 mm. The cartilaginous caudal complex appeared by 6.6 mm NL, and its ossification was completed by 27.2 mm. The fusing of the 1st and 2nd, and the 3rd and 4th hypurals occurred by 8.1 mm. The pectoral girdle contained 5 dermal bones which ossified by 6.6 mm NL, and 3 cartilage replacement bones which ossified by 27.2 mm. The hyoid arch contained 2 dermal bones, six cartilage replacement bones, and 7 branchiostegals (dermal bone) which began to ossify by 15.9 mm. Ossification of the neural and haemal spines was completed by 23.5 mm. Notochord flexion occurred and formed an individual centrum by 6.6 mm NL, and all 24 centra had completely ossified by 12.7 mm. It was previously believed that the hypural complex fusing at a small size at 16.8 mm was an advanced condition. There were 2 plesiomorphic characters, i.e., three predorsals of the back and 3 epurals of the caudal complex, found in S. dumerili. In addition, there were also 2 apomorphic characters, i.e., a stay on the proximal radial and a double fin-ray on the last distal radial of the 2nd dorsal and anal fins, found in S. dumerili.

Key words: Osteological development, Seriola dumerili, Dermal bone.

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