Phyllidiella rosans is a small phyllidiid, usually less than 4cm in size. Here is how it can be recognized :
- the black body is covered with longitudinal pink ridges
- the rhinophores are black
- the foot is pale grey

Phyllidiella rosans can be mistaken for Phyllidiella zeylanica. Here is how to distinguish them :
- the pink ridges are more irregular in P. zeylanica
- the foot of P. zeylanica is whitish
- the gills and oral tentacles are pale grey in P. rosans and dark grey in P. zeylanica

African Indian Ocean