DEVELOPMENT OF JUVENILES OF 4 FLATHEADS (PERCIFORMES, PLATYCEPHALIDAE) OCCURRING IN SOUTHERN JAPAN

The juvenile development of four Japanese flatheads (Platycephalidae), Onigocia macrolepis, O. spinosa, Inegocia japonica and Rogadius asper , is described and illustrated from specimens trawled in Tosa Bay, sou thern Japan. Juveniles of two Onigocia species are diagnosed by an ocu lar flap and absence (O. macrolepis) or presence (O. spinosa) of disti nct dark bars on the body. Inegocia japonica juveniles are distinctive in having a heavily pigmented body and 12 dorsal and anal fin soft ra ys. Rogadius asper has a unique antrorse preopercular spine prior to 1 5 mm SL. During the early juvenile stage, strongly negative aliometric growth occurs in the interorbital region, accompanied by migration of the eyes from the lateral to dorsal surface of the head.