Description ²

Ground color varies from almost white to chocolate brown, but is most commonly pale cream to raw umber; dorsum marked with brown to almost black rings or occasionally irregular blotches of various sizes, number and position; most commonly these rings are arranged in 2 longitudinal rows, one on either side of median line, 3-4 in each row, but this is highly variable, and occasional individuals may lack the brown to black pigment. Rhinophores with 9-30 lamellae. Branchial plumes 6-7, tripinnate, greyish-white to dusky, with whitish tips.

Size ²

Typically about 25mm in length, but individuals up to 150mm have been reported.

Geographic Range ²

Barkley Sound, British Columbia, Canada, to Cabo San Lucas, Baja California, Mexico; Japan.

Notes ²

Preys on several sponges, including: Halichondria panicea & Haliclona permollis. Recently Diaulula odonoghuei was described as a distinct species very similar to D. sandiegensis, but with a southern range limit of Bodega Bay, California.

References ²

ELVIN, David W.. 1976. Feeding of a dorid nudibranch, Diaulula sandiegensis, on the sponge Haliclona permollis. The Veliger 19(2):194-198. PDF

LINDSAY, T. W., J. A. KELLY, A. Y. CHICHVARKHIN, S. F. CRAIG, H. KAJIHARA, J. A. MACKIE, & . VALDÉS. 2016. Changing spots: pseudocryptic speciation in the North Pacific dorid nudibranch Diaulula sandiegensis (Cooper, 1863) (Gastropoda: Heterobranchia). Journal of Molluscan Studies 82(4): 564-574. PDF

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. PDF

McDONALD, G. R. 1983. A review of the nudibranchs of the California coast. Malacologia 24(1-2):114-276. PDF

SOUTHERN CALIFORNIA ASSOCIATION OF MARINE INVERTEBRATE TAXONOMISTS. 2018. A taxonomic listing of benthic macro- and megainvertebrates from infaunal & epibenthic monitoring and research programs in the southern California bight, edition 12, 1 July 2018, xviii + 167 pp. PDF

Additional Info ²

WoRMS

Sources and Credits

1. (c) Gary McDonald, all rights reserved, uploaded by Gary McDonald
2. (c) Gary McDonald, some rights reserved (CC BY-SA)

More Info

• iNat taxon page
• Animal Diversity Web
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