* Elysia mercieri (Pruvot-Fol, 1930) Figure 4K

Material examined.

One specimen 12 mm, SO.

Ecology.

Found upon concrete artificial reefs in soft sediment habitats that formed part of coral restoration efforts. Depth 11-14 m.

Distribution.

Across the Indo-Pacific including the Red Sea (Yonow 2015), Indonesia (Eisenbarth et al. 2018), Japan (Trowbridge et al. 2011), Mariana Islands (Carlson and Hoff 2003), Malaysia, Papua New Guinea, New Caledonia, and Guam (Gosliner et al. 2008). Here representing a first record for Thai waters.

Remarks.

Elysia mercieri is known to be predated upon by the nudibranch Gymnodoris okinawae Baba, 1936 (Nakano and Hirose 2011).