Opisthobranch of the Week Data
Thordisa sanguinea is considered to be very rare on Okinawa as I have seen and collected only a single individual; the animal was found crawling on open sand near patches of coral rubble. Baba (1955) described the species based on two specimens, both collected from Sagami Bay, Japan, during April of 1941 and 1951. I've included a plate (Pl. X, figs. 25-26) of the original drawings illustrated in Baba's publication. One of Baba's two Sagami Bay specimens was found in 10m and the other in "shallow water".
The following external color and morphology are compiled from Baba (1955):
The back is covered everywhere with thick-set pointed papillae which are apt to be developed into distinct filaments at their extremities. The general ground color above is a bright orange-yellow, with 3-4, dark, ocellar markings in the middle line. The dorsal papillae are whitish, the gills and rhinophores are dark brown, and the underside of the body is more pale than is the dorsum. [Baba's description was based on a 13mm animal].