Further cementing the Phyllidiidae as the most confusing family of nudibranchs is Phyllidiopsis xishaensis. Long considered to be Bergh's Phyllidia striata, analysis by Yonow et al (2002) indicates that striata is an Indian Ocean species in the genus Phyllidiella. I have not seen the original description if P. striata and my notes on the living animals below apparently do not exactly match P. xishaensis, but it seems that most phyllidiids show some or sometimes considerable variation. In any case, P. xishaensis is not extremely rare but is hard to find in the Marshalls, known from 20 or more specimens from Enewetak and Kwajalein Atolls. Most were found on lagoon pinnacles and on the seaward reef in ledges and under rocks at depths from about 6 to 20 meters. Four measured specimens ranged from 13 to 16mm in length. Externally, P. xishaensis is very similar to P. annae, which we have seen in Bali and the Philippines (Anilao), differing primarily in the light-colored rhinophores and a bit more frosty whitish margin.
Created 25 December 2006
Updated 16 July 2016