Aldisa williamsi Elwood, Valdes and Gosliner 2000
Blue is not a color I easily associate with opisthobranchs, but in the case of this recently described species, it surely is. This species has a bluish-grey body covered with white tipped tubercles. There is a distinct black band forming an oval on the dorsum and a black line between the rhinophores. Aldisa williamsi bears strong resemblance to the porostome dorid, Phyllidiella pustulosa (Cuvier, 1804), and as the authors point out, probably mimics it. The acid secreting P. pustulosa lacks a dorsally situated gill and has no radula, of course.
Aldisa williamsi is known from Papua New Guinea and photos from Doris #10 Sulawesi, Indonesia.
Batangas, Philippines 1997
Aldisa williamsi is named for Dr. Gary Williams , Associate Curator at the Dept. of Invertebrate Zoology and Geology at the California Academy of Sciences. Gary is also a coauthor of our book Coral Reef Animals of the Indo-Pacific.. Gary is picutred second to left prior to taking in a night dive at Batangas, Philippines with fellow branchers; Clay Carlson, Gary , Dave Behrens, Michael Miller and Terry Gosliner.
The reader is invited you visit Erwin's Medslugs site to sample the many terrific species profiles he offers. Of even more value is Erwin's List of the Opisthobranchs of the World where you can go to find virtually every photograph of sea slugs on the internet today.
Elwood, Hillary R., Angel Valdes & Terrence M. Gosliner. 2000. Two new species of Aldisa Bergh, 1878 (Mollusca, Nudibranchia) from the tropical Indo-Pacific. Proc. Calif. Acad. Sci. 52(14): 171-181.
Perrone, A. 2001. A new species of Nudibranchia of the genus Aldisa Bergh (Gastropoda, Opisthobranchia) Basteria 65: 105-116
David W. Behrens
Pacific Coast Nudibranchs
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