Gymnodoris okinawae

Koh Bon, Phangnga Province, Western Thailand
Photo courtesy of Lawrence Neal
Depth 5 meters

Gymnodoris okinawae (Baba, 1936)

Originally described by Dr. Kikutaro Baba from a single specimen in Okinawa, Gymnodoris okinawae is now known to range far and wide in the Indo-Pacific, from East Africa in the west to as far as Hawaii in the east.

In the Andaman Sea off western Thailand this species can often be found in very shallow water in association with the bright-green turtle weed (Chlorodesmis sp.). Published records indicate that G. okinawae preys upon several Sacoglossan species and it's very likely that in the Andaman Sea area one of the primary food sources will prove to be an undescribed species of Elysia which shares the same shallow-water environments as the Gymnodorid and which also, not surprisingly, lives in the turtle weed. Night time is the best time to see G. okinawae (and also the Elysia sp.) when individuals emerge to actively hunt for food, breed and spawn bright yellow-orange egg rings .

G. okinawae has a translucent whitish to pale-yellow body with indistinct white pustules and orange-yellow spots and scrawls. Convoluted white glands are often visible through the skin. The short conical rhinophores are brownish in colour while the gill branches are translucent white with opaque white at the bases and form a complete circle around the anus. Unlike many of the small and often undescribed Gymnodorid species, this one isn't too difficult to identify.

Specimens observed in the Andaman Sea reach a maximum of 30 mm in length.

Lawrence Neal
Bangkok, Thailand
Aug. 2012

Lawrence at Tulamben, Bali, Indonesia with
Agung Volcano in background

Lawrence is a newspaper journalist based in Bangkok, Thailand. He escapes the office as often as he can to go diving in the rich waters of the Indo-Pacific but his regular dive sites are just down the road along the Gulf of Thailand and the Andaman Sea coast. Lawrence uses a Nikon D200 with a 60-mm or 105-mm macro lens in a Nexus housing together with a pair of Inon Z240 strobes and several wet lenses for the really small stuff.

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