Dirona pellucida

Photograph taken by the Webmaster at Dodd's Narrows, Nanaimo, B.C., Canada
Oct., 1999

Dirona pellucida Volodchenko, 1941

This orange or red-orange Dirona is up to 12 cm in length. It is best known under the name Dirona aurantia Hurst, 1966, but a reexamination of Volodchenko's specimens by Martynov (1997), shows that this name is a junior synonym of D. pellucida , as is the Japanese species D. akkeshiensis Baba, 1957. Volodchenko also erroneously gave the names D. albolineata MacFarland, 1905 and D. picta Eliot, 1905 to specimens of D. pellucida, thus causing considerable confusion in the ranges of these species.

Dirona pellucida has a known range from Norton Sound, Alaska to Puget Sound, northern Washington, across the Bering Sea and in the northern Sea of Japan to Russia. It is found from the intertidal zone to 60 meters. This handsome species has contrasting opaque white flecks on the body and a few on the cerata. There is a white line up the median side of each cerata. The cerata are wide and inflated with pointed tips.

Usually this species is seen only in the winter, laying an irregularly coiled spawn mass with a twisted, pink egg string, from Jan-March (Hurst, 1967). According to Robilliard (1971), juveniles are around from May - August, reaching a large, more conspicuous size in the fall. This species feeds primarily on bryozoans although they eat a variety of other organisms.

Hurst, A. 1967. The egg masses and veligers of thirty northeast Pacific opisthobranchs. Veliger 9: 255-288.
Robilliard, G.A. 1971. Range extensions of some northeast Pacific nudibranchs (Mollusca:Gastropoda:Opisthobranchia) to Washington and British Columbia, with notes on their biology. 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, DalĠnauka, ed. A.V. Rzhavsky (in Russian).

Sandra Millen

Department of Zoology
University of British Columbia
Vancouver, B.C., Canada, V6T 1Z4
Phone (604) 822-2087; Fax (604) 822-2416
Send Sandra E-Mail at millen@zoology.ubc.ca
or visit Sandra's home page

Sandra is pictured at third from left along with Dave Nesheim (LAUPS), Alan Grant (aka the diving dentist), and Mike Miller (webmaster) taking a break between dives at Nanaimo, British Columbia during a field trip to British Columbia in October of this year. We flew up to Seattle, rented a car and continued up into Canada. We didn't see the number of branchs encountered during our '98 trip report, but nevertheless were able to get spectacular video and still footage of what we did see. Dirona pellucida is the second of a series of BOW's as a result of this trip! And of course, diving Dodd's Narrows is always a must when in the Nanaimo area. We were very happy with our boat skipper Rod and the whole Ocean Explorers Diving operation.

Pictured at left are two happy fishermen who had the unfortunate experience to have their fishing skiff capsize off Neck Point. On the other hand, they were fortunate we were diving in the same area and had a skipper (Rod) who also serves as a volunteer in the Canadian Auxiliary Coast Guard. Rod enlisted the aid of Alan and effected the rescue in good speed. Rod was further tested sometime later when Sandra didn't surface going on an hour. We finally located her when she surfaced some hour and twenty minutes later and clamored across the rock spit separating us from the frothing ocean on the other side. All's well that ends well ,but I can tell you we all had some strong liquid refreshment that evening with dinner!

© The Slug Site, Michael D. Miller 1999. All Rights Reserved.