Doris odhneri (MacFarland, 1966)

Description

A large dorid nudibranch reaching up to 20 cm in body length, one of the largest sea slugs on the Pacific coast of North America. The body is uniformly pure white and usually lacks any markings; specimens from Puget Sound and British Columbia occasionally show a faint yellow tint. The dorsum is leathery, and the gills and rhinophores are retractile as in other dorids.

Distribution

The species ranges along the north-east Pacific coast from the Kenai Peninsula, Alaska, southward to Point Loma, California. The first Japanese record is from off the central coast of Iwate Prefecture.

Etymology

The specific epithet odhneri honours the Swedish malacologist Nils Hjalmar Odhner. The Japanese vernacular "Shiro-kuma-umiushi" (literally "polar-bear sea slug") refers to the species' large size and uniformly white body.

Remarks

The diet consists primarily of sponges, especially of the genus Halichondria.

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References

• Austrodoris odhneri n. sp., 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.
• 新称：シロクマウミウシ, 萩原清司 & 田中富士春. (2005). 岩手県中部沿岸から得られた日本初記録の後鰓類 Archidoris odhneri(軟体動物: ドーリス科).
• Doris odhneri, Fernández-Vilert R., Arnedo M.A., Salvador X., Valdés Á., Schrödl M. & Moles J. (2024). Shining disco: shedding light into the systematics of the family Discodorididae (Gastropoda: Nudibranchia). Zoological Journal of the Linnean Society. 203(1): zlae170. https://doi.org/10.1093/zoolinnean/zlae170