* Aeolidiopsis ransoni Pruvot-Fol, 1956 Figure 17A, B

Material examined.

Two specimens 25-30 mm, SB; one specimen 23 mm, CB.

Ecology.

Exclusively recorded on its prey species, the zoanthid Palythoa tuberculosa (Esper, 1805), on which it is extremely cryptic. Depth 1-18 m.

Distribution.

Across the Pacific including Japan (Ono 2004), French Polynesia (Pruvot-Fol 1956), Hawaii (Carmona et al. 2014a), the Philippines, Australia, and Papua New Guinea (Gosliner et al. 2008). Here representing a first record for Thai waters.

Remarks.

Separated from Aeolidiopsis harrietae and A. palythoae (Gosliner, 1985) by the presence of smooth rhinophores and highly elongate body with between 17-23 pairs of cerata. Unlike specimens described by Carmona et al. (2014b) but similar to those described by Rudman (1982), specimens from Koh Tao have rhinophores that lack white tips.