Body elongate and strongly compressed, body depth 3.1 in SL. Mouth large, posterior edge of upper jaw beyond posterior margin of eye. Teeth on upper jaw small and arranged in a single row, those on lower jaw in two rows. Pectoral fin small, shorter than head. Base of soft portion of anal fin slightly shorter than that of dorsal fin. Semi-detached finlets in posterior portions of dorsal and anal fins. Caudal fin deeply forked. No transverse groove on caudal peduncle. Body dark blue dorsally, silver-white ventrally. Anterior part of soft dorsal fin dusky, the posterior pale. Pectoral fin dusky in upper half, plae in lower half. Pelvic and anal fins pale; caudal fin dark yellow.
Distribution:
Honduras to Uruguay.
Remarks:
This species is separable from O. palometa by the higher number of gill rakers(24 against 14〜20) and from O. saurus by the larger mouth (in O. saurus the posterior edge of the upper jaw not reaching to the posterior margin of the eye). (Matsuura)