What is "petalifera"

Petalifera is a genus of sea slugs or sea hares, marine gastropod mollusks belonging to the family Aplysiidae, the sea hares.

Some authors place this genus in a separate family Dolabriferidae. A new study, published in September 2004, has shown that the genus Petalifera is paraphyletic.

(Note: Gastropod taxonomy has been in flux for more than half a century, and this is especially true currently, because of new research in molecular phylogeny. Because of all the ongoing changes, different reliable sources can yield very different classifications.)

A more general description can be found on the page of the superfamily Aplysioidea.