Notes on the morphology of the early stage of the rare bramid genus Eumegistus

Abstract

The morphology of the early stage of Eumegistus was described from three specimens [E. brevorti: 23.0 mm in standard length (SL) juvenile; E. illustris: 5.8 mm SL postflexion larva, and 40.0 mm SL juvenile] recently rediscovered in museum collections. Larval and juvenile pigmentation patterns were reported for the first time for this genus. The 5.8 mm SL postflexion larva of E. illustris had pigmentation on the head and anterior half of the body, through to the middle of the dorsal fin base. In larvae and juveniles of both species, the outer side of the pelvic fin was pigmented. The two juveniles possessed several spines on the lachrymal and protruding rays in the middle of the caudal fin. Although it is known previously that the notochord flexion occurs at 5.0–6.0 mm SL in E. brevorti, the reexamined 5.0 mm SL specimen had the notochord completely flexed. Furthermore, we could not confirm whether the previously studied 4.0 mm SL specimen was E. brevorti because it was badly damaged.