2020 Volume 15 Issue 1 Pages 63-65
A total of 40 robust tonguefish (Cynoglossus robustus) larvae [2.1–10.2 mm body length (BL)] collected from Osaka Bay, eastern Seto Inland Sea were investigated. Those larvae that were smaller than 4 mm BL possessed a single filament-like elongate fin ray emitting from the most anterior dorsal fin. In larvae of between 4 and 5 mm BL we subsequently observed a second short fin ray, next to the first one. At the preflexion stage, 6.5–7 mm BL, the longer of the elongated fin rays extended to about 60% of BL and the shorter one extended to approximately 30–40% of the length of the longer one. These specimens did not develop transverse bands of melanophores laterally on their tails. These characteristics are the same as those presented in hatchery-reared larvae of the same tonguefish. Osaka Bay is also home to larvae from C. interruptus and C. joyneri, both with double elongated dorsal fin rays. These larvae can be easily distinguished from larval C. robustus by counting the myomeres, dorsal and anal fin rays, and by observing the pigmentation pattern on the tail.
