This unidentified species of Gymnodoris is known from Enewetak, Kwajalein, and Bikini Atolls. All have been observed crawling on fine lagoon bottom sand both day and night at depths of 20 meters or more. In the early 1980s they were commonly found while night diving the sand flats off Kwajalein's Ski Boat Area, but few have been sighted since then. Five measured specimens ranged from 12 to 24mm in length. Interesting characters are the wide and pointed anterior foot corners that stretch out almost like miniature wings, and a sharp orange-edged dorsal keel near the tip of the tail. It shares the keel characteristic with Gymnodoris sp. e139, but not the winged anterior foot corners. It was suggested on the Sea Slug Forum that the two might be the same species, but I still think they are different enough to be kept separate. Information on differences in the radular teeth can be found under G. sp. e139. This may be the species figured in Gosliner et al (2018) as Gymnodoris sp. 49.
In all these photos, the animal was moved from its normal sand habitat to a rock to facilitate imaging the subject. They would just about disappear on a white sand background.
The specimen in the two photos below was one of two found crawling on sand at night on 17 July 2010 at a depth of about 12m.
The next few shots show the second specimen, found crawling on sand on 20 October 2008 on a Kwajalein Atoll lagoon reef at a depth of about 7m. This one measured 17mm in length.
When crawling, the animal would stop every few seconds and stick its head under the top layer of sand, but it would not try to bury itself. We suspect it was hunting for food, possibly some kind of opisthobranch mollusk that lives among the sand grains.
Another 7mm specimen was sighted at Kwajalein on 9 March 2013 at night on a lagoon sandy reef.
Created 1 January 2007
Updated 4 December 2021