Acanthodoris hudsoni

Photo courtesy of Rick Ramsey
Scripps Canyon 05/08/05, San Diego, Calif

Acanthodoris hudsoni MacFarland, 1905

Named after the natural history artist, Captain Charles B. Hudson, this species is one of the most commonly miss-identified species in the Pacific Northwest. Like other members of the genus Acanthodoris, the dorsum is covered with tall thin papillations. Because it has a yellow stripe along the edge of the mantle it is repeated likely confused with Cadlina luteomarginata . When distinguishing the two species, remember, Cadlina has low tubercles on the dorsum, not tall papillations, seen on this Acanthodoris hudsoni. Another distinctive character of this species is its very long curved rhinophores.

The other closely related species is Acanthodoris nanaimoensis, who has shorter, red-tipped rhinophores and red-tipped branchial plumes.

Unlike most dorid nudibranchs, Acanthodoris hudsoni feeds on bryozoans, of the genus Alcyonidium sp. This species ranges from Alaska to San Diego, California, and Catalina Island.

Reference: MacFarland, Frank Mace. 1905. A preliminary account of the Dorididae of the Monterey Bay, California. Proceedings of the Biological Society of Washington, 18: 35-54

Dave Behrens
Danville, Calif
May. 2005

Rick and Donna Ramsey

Rick & Donna Ramsey, Escondido, CA NAUI AOW since 10/01. We were introduced to diving in Cancun and Cozumel at a resort course, and we immediately signed up for courses with our local dive shop. After a slow start of only 13 dives per year the first two years, we started going on dive vacations to Kona in 2003, the Florida Keys and Northern Channel Islands in 2004, and the Southern Channel Islands, Cortez Banks, and La Paz in 2005. We also try and do a local boat and shore dive per month and are now averaging 60 dives per year.

We are nudibranch enthusiasts, so we picked up an Olympus Stylus 300 with an Olympus PT-016 housing in 2004. Donna spots most of the small ones that I take pictures of, and I find a lot of the bigger ones. It has been an extremely rewarding experience to share all of our pictures with other divers in the albums I have posted on / Rick's Picks. We also like to hunt for scallops and lobster, but lobster hunting hasn't been as rewarding as shooting nudis.

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Puerto Vallarta, Mexico
March 2005

Ali Hermosillo and Dave Behrens

Author: Pacific Coast Nudibranchs
Co-Author Coral Reef Animals of the Indo Pacific
Proprietor of Sea Challengers Natural History Books

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