Cadlina luteomarginata from Oregon

August 24, 2001
From: Jeff Goddard

Hi Bill,
Here is some information on Cadlina luteomarginata from the west coast of North America that may help clear up the identity of Paul Young's Cadlina from New England.

Cadlina luteomarginata from the Pacific always have a dorsum with a yellow border and yellow-capped papillae. The background white is quite opaque, and I have never noticed the deep-set, yellow defensive glands so obvious in Paul Young's and Bernard Picton's photos of Cadlina laevis.

Cadlina luteomarginata from Cape Arago, Oregon feed on at least 13 species of spiculate sponges, primarily Zygherpe hyaloderma, Hymendectyon lyoni, Myxilla incrustans and Hymedesmia sp. However, the largest number of individuals are found feeding on the dendroceratids Aplysilla glacialis and Pleraplysilla sp. (personal observations). I have never found C. luteomarginata feeding on Halisarca. At Cape Arago, Halisarca is the sole prey of Hallaxa chani. Cadlina modesta also preys on Halisarca, but is more commonly found preying on Aplysilla glacialis. Y-maze trials show that C. modesta prefers the latter over the former (personal observations), and I have never found C. modesta feeding on any other sponges or seen sponge spicules in its gut.

The radular morphology of the above species appears to reflect their diets. Cadlina luteomarginata has strongly hooked lateral teeth, while both Hallaxa chani and Cadlina modesta have nearly straight, saw-like laterals. According to the illustrations in Thompson & Brown (1984), C. laevis, which specializes on Halisarca thoughout much of its range, has lateral teeth very similar to those of C. modesta and Hallaxa. I agree with you and Bernard Picton in identifying the sponge in Paul Young's photos as a 'slime sponge', probably Halisarca. Therefore, I think that his specimens are a color form of Cadlina laevis or an undescribed species. I doubt they are C. luteomarginata.

I have attached an old photo of mine of Cadlina luteomarginata on Pleraplysilla sp. from Cape Arago, Oregon. Hopefully, someone will send in a better, in situ photo of this striking species.

Best wishes,
Jeff Goddard

goddard@lifesci.ucsb.edu

Goddard, J., 2001 (Aug 24) Cadlina luteomarginata from Oregon. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/4894

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