* Hypselodoris decorata (Risbec, 1928) Figure 10K

Material examined.

Two specimens 8-18 mm, CB.

Ecology.

Abundant among reef rubble, in particular under dead fungiid coral skeletons, in shallow coral reef areas. Rare in other habitats. Depth 2-12 m.

Distribution.

Widespread throughout the Indo-Pacific including Malaysia, Philippines, Indonesia, Papua New Guinea, New Caledonia, Vanuatu, and the Marshall Islands (Epstein et al. 2018). Here representing a first record for the Gulf of Thailand. Hypselodoris decorata was recorded as Hypselodoris maculosa (Pease, 1871) from the Andaman coast by Chavanich et al. (2013).