Studies on the Larvae and Juveniles of the Sinistral Flounders-II. Chascanopsetta lugubris

Abstract

Three postlarvae of the family Bothidae certainly identified as Chascanopsetta lugubris Alcock were obtained from the southwestern area of Japan.They have the following characteristic features: immense size (34 to 120 mm in standard length), elongate second dorsal spine, high dorsal and anal fins, greatly elongate and tapering posterior process of the pelvic bone, the expansion of the intestinal coil beyond the body, and a great number of dorsal and anal fin rays and vertebrae.The species metamorphoses at about 121 to 125 mm in standard length.The relative growth before and after the metamorphic stages, which was observed among several body parts, is divided into two types.The depth of body and the longest dorsal ray make a sudden degression, while the head length, the eye diameter, the pectoral fin length, and the maxillary length show remarkable growth.Probably, the largest of the present specimens, measuring 120 mm in standard length, 135 mm in total length, is the largest larval flounder ever recorded.