Armina californica
(Cooper, 1863)

Suborder: ARMININA
Family: Arminidae


West coast of North America from the Gulf of Alaska south to Panama.


Channel Islands, California, USA, 1987. On dark sand at a depth of about 12 meters. Photos: Scott Johnson

Grows to 70mm. Like most species of Armina, it lives in sand or muddy regions and feeds on sea pens, in particular Ptilosarcus gurneyi and Renilla koellikeri. It stays buried during the day, only coming to the surface to feed at night. It causes a spectacular light show when it is feeding on the sea pen Renilla koellikeri because that species produces luminescent flashes every time it is bitten.

• Bertsch, H (1968) Effect of feeding by Armina californica on the bioluminescence of Renilla koellikeri. The Veliger, 10(4): 440-441.
• Cooper, J. G. 1863. Some new genera and species of California Mollusca. Proceedings of the California Academy of Natural Sciences, 2: 202-207.
• MacFarland, F. M. 1966. Studies of opisthobranchiate mollusks of the Pacific coast of North America. Memoirs of the California Academy of Sciences, 6: 1-546, pls. 1-72.

Authorship details
Rudman, W.B., 2002 (October 28) Armina californica (Cooper, 1863). [In] Sea Slug Forum. Australian Museum, Sydney. Available from

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