Occurrence of Elysia serca Marcus in Florida, with notes on the synonymy and biology of the species

Elysia clena Marcus and Marcus 1970 is synonymized with E. serca Marcus 1955 on the basis of morphological and biological observations. Radular morphology and pattern of dorsal veins show overlap in various geographical populations in Florida, and reproductive anatomy does not show sufficient differences to validate separation of two species. E. serca feeds on 3 genera of seagrasses, Halophilo, Halodule, and Thalassia. The shape of radular teeth, buccal anatomy, and pattern of dorsal veins are very similar to E. catulus (Gould 1870), the only other ascoglossan reported to feed on seagrasses.