Thuridilla cf gracilis is similar to the one we are callilng T. cf ratna, but with a darker black background and differently colored rhinophores. Our single specimen was found at Utirik Atoll in shallow water on the lagoon side of Eerukku Island on 10 June 1983 and is almost certainly not the Elysia gracilis originally described by Risbec (1928) from New Caledonia (figure at bottom of the page). Our animal looks similar to figure 6a of Thuridilla gracilis in Martín-Hervás, et al (2021), although their description is somewhat different; in particular, they describe orange tips to the rhinophores and a bright inner margin to the parapodia while ours lack the orange on the rhinophores and my notes indicate a black inner parapodial margin with brownish submargin. We did find typical Thuridilla cf ratna at Utirik on the same trip and they had a quite different overall appearance.
The figure of Elysia gracilis is copied from plate X figure 5 of Risbec (1928).
Created 22 January 2007
Updated 20 October 2021