Phyllidia mimicry

May 18, 2002
From: Erwin Koehler

Dear Bill,
Here is a shot of Britta Hochberger (email from Indonesia, Nabucco Island, divesite "Sand Rich". It shows a juvenile egg-cowrie Ovula ovulum which appears to mimic Phyllidia madangensis.

Size 1-2 cm, Depth 14m, 17 March 2002


Koehler, E., 2002 (May 18) Phyllidia mimicry. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Thanks Erwin,
It certainly has similarities to P. madangensis but 'mimicry' has a special biological meaning and it is very difficult to demonstrate that 2 animals that look alike are the result of some long term evolutionary selection process. Even the idea that the juvenile holothurian in Wolfgang's wonderful photo is mimicking a species of Phyllidia is based on intuition rather than evidence.
Bill Rudman

Rudman, W.B., 2002 (May 18). Comment on Phyllidia mimicry by Erwin Koehler. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from



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