Thorunna australis (Risbec, 1928)

This small nudibranch was not especially uncommon at Enewetak Atoll and is sometimes seen at Kwajalein as well. They live under rocks at depths of 4 to 10 meters on lagoon reefs and sometimes on pinnacles, where they can often be found eating the tan-colored sponge shown in the photo below. The specimen on the right is carrying a rider: a commensal copepod, which is the roundish blob about midway along the body. Thirty-three specimens we've measured ranged from 6 to 18mm in length.

Here is another pair eating its tan-colored prey sponge on a Kwajalein Atoll lagoon pinnacle.

This species deposits ruffled egg masses, as in the two photos below.

Here is another specimen munching away at its tan prey sponge.

Created 3 January 2006
Updated 14 January 2007