Antiopella barbarensis (J. G. Cooper, 1863)

What is the Santa Barbara janolus?

The Santa Barbara janolus (Antiopella barbarensis), also called the cockscomb nudibranch, is a colourful cladobranch sea slug of the California coast, its back covered with cerata that glow orange-gold and are often tipped with iridescent blue.

Description

A cladobranch nudibranch a few centimetres long. The translucent body is densely covered on the back with numerous slender cerata; these appear orange to gold from the digestive gland within and are frequently tipped with bright, iridescent blue. Between the two rhinophores sits a low, frilled crest (caruncle) with a finely scalloped edge — the feature behind the name "cockscomb nudibranch".

Distribution

Ranges along the Pacific coast of North America, mainly off California, from San Francisco Bay south to Baja California and the Gulf of California, Mexico. It occurs from tide pools into shallow water.

Etymology

The specific epithet barbarensis means "of Santa Barbara", after Santa Barbara, California.

Remarks

It feeds on bryozoans. A very similar northern species, Antiopella fusca, shares the California coast, and the two form a closely resembling species pair.

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References

• Aeolis barbarensis n.sp., Cooper J.G. (1863). On new or rare Mollusca inhabiting the coast of California — No. II. Proceedings of the California Academy of Natural Sciences. Series 1, 3: 56-60.
• Antiopella barbarensis, Behrens D.W., Hermosillo A., Fletcher K. & Jensen G.C. (2022). Nudibranchs & Sea Slugs of the Eastern Pacific. Molamarine.