Phyllodesmium magnum is a species of sea slug, an aeolid nudibranch, a marine gastropod mollusc in the family Facelinidae.[1]
This species was described from New Caledonia with additional material from NW Australia, the Marshall Islands and Hong Kong. The distribution of Phyllodesmium magnum includes North Kermadec and Guam.[2]
This species grows to 130 mm in length. It is one of the Phyllodesmium species which contain zooxanthellae.
Phyllodesmium magnum feeds on a soft coral Sinularia sp.