Plocamopherus imperialis feeding

February 27, 2007
From: Leanne & David Atkinson

Hi Bill,
We were excited to find this Plocamopherus imperialis feeding. You can actually see a chunk of its prey item in its mouth. Thought this might be of interest to you.

Locality: The Pipeline, Port Stephens, 10 metres, New South Wales, Australia, Pacific, 10 February 2007, Silty, sandy bottom with scattered sponges, ascidians, bryozoans, soft corals and hydroids.. Length: 60 mm. Photographer: Leanne & David Atkinson

Leanne & David Atkinson


Atkinson, L. & D., 2007 (Feb 27) Plocamopherus imperialis feeding. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Dear Leanne & David,
Thanks for these nice photos of Plocamopherus feeding on bryozoans. As I say on the Fact Sheet, its relatives feed on bryozoans and it is often found on bryozoans, but until now I knew of no actual observation of it eating them. As they say - seeing is believing. Thanks.

In a message I am posting today on P. ceylonicus [#19542] I discuss the bioluminescent spheres on the lateral papillae in that species and how it seems they can be damaged and regrow. In your middle right photo I have ringed the sphere in this species. if you compare it with the sphere, and its papillae, on the species Fact Sheet it seems that the sphere in your animal is in the process of regrowth. The spheres in P. imperialis differ from those in P. ceylonicus. While in P. ceylonicus they sit at the tip of a relatively narrow papilla (or stalk), In P. imperialis, the papilla is proportionally much larger, being a large swollen base, with the sphere at one corner. Also In P. imperialis the spheres are usually found only on the last papilla on each side, while in P. ceylonicus they can be on any of the four posterior papillae.

Best wishes,
Bill Rudman

Rudman, W.B., 2007 (Feb 27). Comment on Plocamopherus imperialis feeding by Leanne & David Atkinson. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

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