Aldisa pikokai from Hawaii

March 20, 2002
From: Scott Johnson

Hi Bill,
Attached is an addition to the Aldisa section of the Forum. These three Aldisa pikokai range in size up to about 20mm and in color from orange to bright red. These photos are all from Oahu, Hawaii, where it is a relatively common species on shallow subtidal reefs, often found exposed on the reef or feeding on an encrusting red sponge at night. Specimens hide away and are almost never observed during the day. The animals are characterized by the often sharp longitudinal and transverse ridges that crisscross the dorsum, and by three crater-like depressions running along the middorsal line. The craters usually have darker oval spots on their 'floors'. Although we originally thought this was found only in Hawaii, I have since come across two typical specimens at Kwajalein, Marshall Islands. A similar and possibly unnamed species [see separate message]from Hawaii shares the same habitat but lacks the ridges and has different dorsal craters.

Johnson, S., 2002 (Mar 20) Aldisa pikokai from Hawaii. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Thanks Scott,
After those remarkable phyllidiid mimics such as Aldisa erwinkoehleri, it's nice to see some good old sponge mimics
Bill Rudman

Rudman, W.B., 2002 (Mar 20). Comment on Aldisa pikokai from Hawaii by Scott Johnson. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from


Aldisa pikokai

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