"Phyllidiella pustulosa and its various look-alike species are confusing and hard to distinguish. I have changed my mind many times about identifications of the different species, but I don't think I or anyone else has all the answers yet. That said, I have a hard time believing the animals in this picture are the same as the definitive Phyllidiella pustulosa seen in some of the other pictures. Their rhinophores do not look quite black enough and the dorsal color and pattern seem distinct from typical Phyllidiella pustulosa. It could be just a variation of Phyllidiella pustulosa, but it seems unlikely to me that two such similar looking specimens would find each other amidst all the other, more typical Phyllidiella pustulosa found on Micronesian reefs. Still, I do not have a better name to give it. Best at this time I think to call it a questionable variation of Phyllidiella pustulosa that needs more research."