Halgerda tessellata Bergh, 1880
Halgerda tesselata is one of those mind blowing psychedelic species. The colors and patterns on the dorsum make you wonder what mind expanding drug the designer of this species was using. It is also a good example of the variation in color exhibited between individuals of some species. The two specimens seen here in Mike's photo were found on the same rock.
Dorsal ridges connect the dorsal tubercles of this species. They are steep and pointed, and are burnt orange in color. In some specimens these orange lines are edged by a think black line, which is absent in others, as seen here. The depressions between the ridges are dark brown to black with white specks and/or spots. The white specks often become more dense near the edge of the mantle, which is yellow. Other examples of variation in color can be seen in Atsushi Ono's Opisthobranchs of Kerama Islands, our Coral Reef Animals of the Indo-Pacific, and Helmut Debelius', Sea Slug Guide. The rhinophores and gills are tipped with black.
The species has a wide distribution being found from East Africa and Madagascar to the Maldives, Thailand, Micronesia and Australia. Specimens grow to over 50 mm in length.
Taxonomic information courtesy of Dave Behrens
David W. Behrens
Pacific Coast Nudibranchs
Send Dave mail at firstname.lastname@example.org