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 pinnacles. Thirty-three specimens we've measured ranged from 6 to 18mm in length.

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.

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

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

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

The pair below were on a Kwajalein Atoll lagoon pinnacle, feeding on sponge under a rock at about 10m on 13 October 2009.

The animal below was under a rock on a shallow west lagoon reef at a depth of about 6m on 6 August 2012.

Another under a large dead table coral in February 2016.

Created 3 January 2006
Updated 1 March 2016

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