Armina californica (Cooper, 1863)

Description

An oval, rather flattened sea slug reaching about 5–10 cm in length. The dorsum is brown to greyish-brown and densely covered with fine longitudinal ridges running along the length of the body; because these ridges are pale cream, white or pinkish, the animal looks strikingly striped. The rhinophores sit at the front of the body, and the animal burrows in sand or mud.

Distribution

Widespread along the west coast of North America in the northeastern Pacific, from the Gulf of Alaska and Vancouver Island, Canada, south to Panama. It lives on sandy and muddy bottoms from the low intertidal to about 80 m (with records from deeper water). The species was originally described from California.

Etymology

The specific epithet californica means “of California,” after the region where it was found.

Remarks

A predator of sea pens. It burrows through soft sediment and feeds on pennatulaceans such as Ptilosarcus gurneyi. These sea pens are known to luminesce with a bluish light when disturbed.

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References

• Pleurophyllidia californica 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.
• Armina californica, Behrens D.W., Hermosillo A., Fletcher K. & Jensen G.C. (2022). Nudibranchs & Sea Slugs of the Eastern Pacific. Molamarine.