* Goniobranchus sinensis (Rudman, 1985) Figure 10D, E

Material examined.

Three specimens 20-55 mm, CP.

Ecology.

Among rocks and corals at offshore rocky pinnacles. Depth 9-22 m.

Distribution.

Across the Indo-Pacific including the Gulf of Oman (Fatemi and Attaran 2015), India (Sreeraj et al. 2012), Malaysia, Indonesia, China, and Japan (Gosliner et al. 2008). Recorded from the Gulf waters of Thailand (Chavanich et al. 2013).

Remarks.

Incorrectly identified as Goniobranchus trimarginatus (Winckworth, 1946) by Mehrotra and Scott (2016). Subsequent observations indicate that specimens from Koh Tao are Goniobranchus sinensis, with individuals being recorded with marginal and submarginal bands ranging from complete to broken.