Re: Dendronotus from New England

Dear Jussi,
I wish it were so simple! My first move was to read Gordon Robilliard's work but that only made it more confusing, particularly when I have only photos to work from. If we first consider the yellow/white spotted species;
Robilliard (1970) reviews two species which have been reported from the north western Atlantic and could be this species.
• D. frondosus is highly variable in colour many mottled with various proportions of brown, white and yellow.
• D. robustus (Verrill, 1870). Robilliard has seen no live animals but he cites from Verrill's description that the animal has "a pale greyish ground color liberally sprinkled with small yellow spots..."

In Robilliard's 1972 paper he describes another possibly relevant species, from the northeast Pacific:
• D. albopunctatus Robilliard, 1972. This has small white spots but also ahsa scattering of larger red brown spots as well.

And concerning Paul Young's brown dendronotid, it certainly doesn't fit Verrill's colour description of D. robustus. It could possibly be D. frondosus but I fear I am only guessing.

For these reasons I was hoping that there is someone out there with a knowledge of the fauna of the Nth American east coast who had a personal knowledge of these species and could stop me blundering around in the literature. And as a final comment I refer to Sherman Bleakney's book:
" In Atlantic Canada we have two large pale orange, essentially identical bushy-backed slugs. If your specimen is from intertidal or shallow water it probably is Dendronotus frondosus. If it is from depths greater then 18m, it probably is Dendronotus dalli. Anything from in between needs to have its teeth examined ..."

Cheers,
Bill Rudman