Larval development of Etropus longimanus (Paralichthyidae) and Symphurus trewavasae (Cynoglossidae) off the Buenos Aires coast, Argentina

Abstract

The larval development of Etropus longimanus and Symphurus trewavasae (Pleuronectiformes) off the Buenos Aires coast was described. Both species have an elongated body; however, as the total length of Etropus longimanus larvae increased, their body became deeper. In Symphurus trewavasae the intestine was noticeably coiled. In E. longimanus the notochord flexion started at 3.9 mm and was completed at 5.0 mm standard length (SL). Vertebral formation began in larvae with a 4.6 mm SL and the definitive number of vertebrae (34-39) was observed in larvae of 4.8 mm SL. The dorsal fin had two elongated rays and the pelvic fins had only one. In Symphurus trewavasae the notochord flexion began at 5.9 mm and was completed at 8.0 mm SL. Migration of the right eye was completed in the metamorphic stage at 10.5 mm SL. Vertebral column ossification finished in flexion larvae of 6-7 mm SL, with a total number of 48-50 vertebrae. Four elongated rays of similar length were observed on the dorsal fin.

Keywords

• pleuronectiformes
• early development
• larvae
• flatfish
• tonguefish
• sw atlantic