Diaulula sandiegensis (Cooper, 1862)

What is the San Diego dorid?

The San Diego dorid (Diaulula sandiegensis) is a pale, brown-spotted dorid nudibranch of the northeastern Pacific coast of North America.

Description

A firm-bodied dorid, whitish to greyish-tan, marked with numerous irregular chocolate-brown spots — some ring-shaped, some solid — that extend onto the mantle margin. The dorsum has a velvety texture of fine tubercles.

Distribution

Northeastern Pacific along the west coast of North America, from northern California south to Baja California, Mexico. The species was originally described from San Diego Bay, California.

Etymology

The specific epithet sandiegensis refers to San Diego, California, the type locality.

Remarks

A sponge feeder. It was long treated as a single wide-ranging North Pacific species, but recent work showed that populations of the northern North Pacific, including Japan, belong to a separate species, Diaulula odonoghuei; D. sandiegensis in the strict sense is restricted to the southern part of the west coast of North America.

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References

• Doris sandiegensis n.sp., Cooper J.G. (1863). On some new genera and species of California Mollusca. Proceedings of the California Academy of Natural Sciences. Series 1, 2: 202-207.
• Diaulula sandiegensis (Cooper, 1863), Valdés Á. & Bertsch H. (2010). Two new species of dorid nudibranchs from the Gulf of California (Mar de Cortés), Baja California, Mexico (Mollusca, Opisthobranchia). Spixiana. 33(1): 1-11.
• Diaulula sandiegensis, Hallas J.M., Simison W.B. & Gosliner T.M. (2017). Changing spots: pseudocryptic speciation in the North Pacific dorid nudibranch Diaulula sandiegensis (Cooper, 1863) (Gastropoda: Heterobranchia). Journal of Molluscan Studies. 83(1): 1-15. https://doi.org/10.1093/mollus/eyw037
• Diaulula sandiegensis, Behrens D.W., Hermosillo A., Fletcher K. & Jensen G.C. (2022). Nudibranchs & Sea Slugs of the Eastern Pacific. Molamarine.