Phyllidia coelestis

Order : NUDIBRANCHIA
Suborder : EUCTENIDIACEA
Infraorder : DORIDACEA
Superfamily : PHYLLIDIOIDEA
Family : Phyllidiidae

DISTRIBUTION
Common on tropical reefs throughout the Indo-West Pacific Ocean. Known from the western Pacific Ocean, South China Sea, Timor Sea and across the Indian Ocean to South Africa.

Notes compiled from Brunckhorst, 1993:
Phyllidia coelestis can be distinguished from other similar-looking phyllidiids by colour and pattern: in particular the “Y” shape of the blue-grey dorsal ridges; the yellow-capped mid-dorsal tubercles (which never form a median ridge as in Phyllidia varicosa); the evenly tuberculate, broad, blue-grey mantle margin; and the uniformly grey foot without a dark stripe