Dirona pellucida
Volodchenko, 1941

Order: NUDIBRANCHIA
Suborder: ARMININA
Family: Dironidae

DISTRIBUTION

Known from Coos Bay, Oregon at the southern end to Norton Sound, Alaska and west across the Bering Sea to Russia and the Sea of Japan. Also recorded in Forum from Sth Korea.

PHOTO

near Mayne Island, British Columbia, Canada, 20 m. Size:  approx: 100 mm. Photo: Clinton Bauder.

For years, opisthobranch workers along the northeastern Pacific coast of Nth America knew this species as Dirona aurantia Hurst, 1966.  Martynov (1997), showed that it was originally described from Russia, in 1941 as Dirona pellucida.  The Japanese species D. akkeshiensis Baba, 1957 is also the same.

This brilliantly colored Dirona reaches 120 mm in length.  Its body is bright orange to reddish-orange, with scattered white granular spots.  A tapering while line extends up the margin of each ceras. It feeds on the bryozoan, Bugula pacifica.  Its recorded range extends from Coos Bay, Oregon at the southern end to Norton Sound, Alaska and west across the Bering Sea to Russia and the Sea of Japan, south to Korea.

• Baba, K. (1957) A revised list of the species of Opisthobranchia from the northern part of Japan, with some additional descriptions. Journal Faculty Science, Hokkaido Imperial University, series 6, Zoology, 13(1-4): 8-14.
• Hurst, A (1966) A description of a new species of Dirona from the north-east Pacific. The Veliger 9(1): 9-15.
• Volodchenko, N. I. (1941) New nudibranchiate molluscs from seas of the far-east of the U.S.S.R. Investigations of the far eastern seas of the U.S.S.R. 1:53-72, pls. 1-4. [Issledovani Dal'nevostochnykh Morei S.S.S.R.]. [In Russian ].
• Robilliard, G.A. (1971) Range extensions of some northeast Pacific nudibranchs (Mollusca: Gastropoda:Opisthobranchia) to Washington and British Columbia, with notes on their biology. The Veliger, 14: 162-165.
• Martynov, A. V., 1997. Opisthobranch molluscs of coastal waters of Commander Islands with notes on their fauna in the Far-East Seas of Russia. [In] Donnaya fauna i flora schelifa Komandorskikh Ostrovov. pp. 230-241. Vladivostok, DalÕnauka, ed. A.V. Rzhavsky (in Russian).

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