Dendronotus robustus from Massachusetts, USA

March 8, 2007
From: Alan Shepard

Bill -
I saw Erling Svensen's wonderful photos of Dendronotus robustus [#19087 ] and figured I might as well send you my rather poor shot of the species. I have encountered this species only once and unfortunately it was at the end of a dive with only one frame left in the camera and a framer a bit too small for the species. The result was a shot which does not show the entire nudibranch and a rather poor shot at that. The coloration was a yellowish gold with numerous spots.

Locality: Folly Cove, Gloucester, 4 metres, Massachusetts, USA, Atlantic Ocean, summer 2003, Sandy bottom edged by rocks and boulders. Length: 5 centimetres. Photographer: Alan Shepard

Anyway I encountered it in the summer of 2003 in only 4 metres of water in a very sandy area. It was fairly large compared to other local species at just over 5 centimetres. I know of only one other local underwater photographer that has been able to take a photograph of D. robustus locally and he encountered it twice in the same cove at a depth of about 20 metres. His specimens were red with the typical spots.

This is one species that I really wish I would encounter again.

Alan Shepard

Shepard, A., 2007 (Mar 8) Dendronotus robustus from Massachusetts, USA. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Dear Alan,
Thanks very much for this photo of an animal from the other side of the Atlantic than Erling's. Don't worry that it isn't perfect - imperfections add reality to the Forum. Your photo shows an almost identically coloured animal, and if I look carefully I am pretty sure that the gills, instead of having a single trunk, are a cluster of two or three stalks, as in Sven's animal.

Best wishes,
Bill Rudman

Rudman, W.B., 2007 (Mar 8). Comment on Dendronotus robustus from Massachusetts, USA by Alan Shepard. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from