August 17, 2005
From: Jeff Goddard
Concerning message #14560
I think the aeolid in Terry Strait's photo may be Cumanotus sp. (previously Flabellina sp. 1 of Behrens, 1991), not Cuthona divae. The body is much wider in Cumanotus, and I have never seen Cuthona divae with the tips of its cerata curled like that. Also, the cerata cores of the Cumanotus sp. pictured in Behrens (1991) ramify much more than in Cuthona, which also appears to be the case here. Finally, Cumanotus sp. inhabits soft sediments, while Cuthona divae usually seeks out hydroids on rock substrates. Behrens (2004) describes a unique, cerata-propelled swimming behavior in Cumanotus sp. which eventually may help pin down the identity of the Terry's specimen; otherwise, we need to examine the radula.
firstname.lastname@example.orgGoddard, J.H.R., 2005 (Aug 17) Re: Cuthona divae from California. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/14582
I wondered about its identity. That's why I asked for the feeding photos. Since Cuthona divae seems to feed on athecate hydroids such as Hydractinia, I thought perhaps this one's food choice could give some clues. Looking at the photo 156 in Dave's 1980 edition I can see a white streak running form the ceratal tip down one edge of each ceras. I had noticed a similar white streak on the cerata of Terry's animal so you may have the right answer. While looking at Dave's book I also noticed photo 159 'burrowing aeolid'. It looks very like that as well. Could it be the same thing?
Perhaps Terry can see if these animals swim or burrow next time he comes across them?