Trapania darwini
Gosliner & Fahey, 2008

Order: NUDIBRANCHIA
Suborder: DORIDINA
Superfamily: ANADORIDOIDEA
Family: Goniodorididae

DISTRIBUTION

 Known from the Galapagos Islands, tropical eastern Pacific.

PHOTO

Upper: CASIZ 079163, Isla Espanola, Galapagos Islands, 7 mm. Photo: T. Gosliner. Lower: CASIZ 172859. Radular morphology. Scale =10 µm. [From Gosliner & Fahey 2008: Fig. 26C,D].

The body is translucent white with a roughly symmetrical pattern of brown elongate patches of brown which coalesce with each other. The brown patches are punctuated with elongate white spots of varying size.  The
posterior tip of the foot is yellow. The oral tentacles are brown with a white tip and the dorso-lateral processes, the rhinophores and the gills are translucent clear with yellow tips.

The living animals grow to at least 9 mm in length.

Gosliner & Fahey mention that this species closely resembles Trapania goslineri Millen and Bertsch, 2000 from the Pacific Coast of Baja California and mainland Mexico. This is a view which I strongly agree with. In external colour the difference is that the brown pigmentation in T. goslineri forms solid elongate brown spots, but the arrangement of these brown marks is almost identical to those of T. darwini. They also say that the radular morphology of T. darwini most closely resembles T. goslineri. However they consider the difference in denticulation to be significant. However the differences they mention can be found within their photos of two different parts of the radula of a specimen of T. darwini.  I would not be surprised if further collecting along the tropical eastern Pacific coast were to show these two 'species' were colour variants of one.

• Gosliner, T.M. & Fahey, S.H. (2008)  Systematics of Trapania (Mollusca: Nudibranchia: Goniodorididae) with descriptions of 16 new species Systematics and Biodiversity, 6 (1): 53-98

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