In the early days, I identified this as the Hypselodoris daniellae of Kay & Young (1969). Only when I found the real Thorunna daniellae did I recognize the difference. A photo on the T. daniellae page that shows the two species together illustrates the color differences, which are reinforced by differences in radular morphology. While I saw a few specimens at Makua and Kam Reef, Oahu, and an additional six at Kure Atoll, they were most common at Magic Island, where 172 were counted in 57 hours of timed nudibranch searching.
The specimen below is feeding on the thin tan-colored sponge under its head. Many species of Thorunna appear to feed on a similar or perhaps even the same sponge.
Created 20 April 2009