Doriopsilla gemela from California

Dear Chris,
I guess this is Behrens' 'Dendrodoris sp. 1' which has been named Doriopsilla gemela by Gosliner, Schaefer & Millen (1999}. However I can't see the colour of the gills which should be yellow or orange if it is D. gemela.

D. gemela is very similar in colour to D. albopunctata with small opaque white spots, but the mantle appears smoother, although it has some minute tubercles. It grows to 40 mm and differs from D. albopunctata in having deep yellow or yellow-orange gills rather than the white of D. albopunctata. Another major difference is the shape of the egg ribbon and the type of larval development. The egg ribbon forms a flattened spiral of 3 whorls, and the larvae are lecithotrophic [planktonic, free-swimming but non-feeding]. The egg ribbon of D. albopunctata by comparison is a spiral attached along one edge. The larvae are planktotrophic [planktonic, free-swimming but feeding]. This again shows the value of photographing and recording egg ribbons if their parent can be confidently identified, because they can often give us clues to the presence of more than one species in a group of very similar looking animals.

• Gosliner, T. M., Maria C. Schaefer, & Sandra V. Millen. (1999) A new species of Doriopsilla (Nudibranchia: Dendrodorididae) from the Pacific Coast of North America, including a comparison with Doriopsilla albopunctata (Cooper, 1863). The Veliger, 42(3): 201-210.

Best wishes,
Bill Rudman