Glossodoris rufomarginata (Bergh, 1890)

Like Glossodoris atromarginata, G. rufomarginata seems rare in the Marshalls unless you search in the caves and ledges of the windward seaward reef's groove and spur system. This zone, where the seaward slope meets the intertidal reef, is heavily pounded by crashing waves and intense surges during most of the year. Only during the doldrums is it possible to dive this area. This species feeds on a dark gray clumping sponge that grows in the groove and spur ledges. Occasionally the sponge grows a bit too massive and is torn off by the surge. The sponge colony, sometimes carrying a nudibranch rider, washes across the intertidal reef and ends up in the lagoon. We have found sponges still with nudibranchs attached sitting on sandy lagoon slopes. Unfortunately, this sponge, the sole prey of G. rufomarginata, does not normally live in this area, so once the sponge is gone, the nudibranchs probably starve. We have seen G. rufomarginata at Enewetak, Kwajalein, and Bikini Atolls in the Marshalls.

The individual below has an abnormality. It's two rhinophore pockets are connected, so both rhinophores extend from the body from the same hole.

This is the egg mass of Glossodoris rufomarginata.

The anus opens to the outside world in the middle of the cluster of gills. This animal is on its prey sponge.

The species can be quite variable. The two individuals below were found on the same chunk of prey sponge.

Created 3 January 2006
Updated 26 November 2007