Corambe pacifica MacFarland & O'Donoghue, 1929

Description

A tiny disk-like dorid almost indistinguishable from a young colony of the bryozoan host. Body elliptical and flattened with the notaeum extending beyond the foot all round; the notaeum margin is wide and thin, with a deep median circular notch behind. Foot rounded equally at front and back, with a deep median anterior notch exposing the mouth. Head small, fully covered by the notaeum, its angles produced into short blunt outward-directed tentacles. Rhinophores retractile into low, entire, thin-margined sheaths. Six to 12-14 simple pinnate gill plumes per side, decreasing in size anteriorly, restricted to the posterior third of the body, with a single median plume usually above the anus. Dorsum pale translucent grey, the central area marked out by the pale yellow-orange liver showing through; surrounded by a whitish zone formed by the foot below; the outermost transparent zone bears irregular radiating baryta-yellow lines that mimic the cell walls of Membranipora. Lives on bryozoan colonies (Membranipora membranacea) growing on kelp and seagrass.

Distribution

Northeast Pacific, from Alaska through California to Mexico, on coasts where its bryozoan host is abundant. The type localities are Monterey Bay (California) and Nanaimo (British Columbia). Specimens reported from Japan may represent a similar but distinct species (the species is not considered to occur in the western Pacific).

Etymology

The specific epithet pacifica refers to the Pacific Ocean, the type-locality region — distinguishing the species from the previously described Atlantic / Mediterranean members of the genus.

Remarks

Originally described in 1929 as "A new species of Corambe from the Pacific coast of North America" (Proceedings of the California Academy of Sciences, ser. 4, 18(1): 1-27, pls. 1-3). Co-occurs with the very similar Corambe steinbergae on the same host bryozoan.

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References

• Corambe pacifica, MacFarland F.M. & O'Donoghue C.H. (1929). A new species of Corambe from the Pacific coast of North America. Proceedings of the California Academy of Sciences, fourth series, 18(1): 1-27, pls. 1-3.
• Corambe pacifica, Behrens D.W., Hermosillo A., Fletcher K. & Jensen G.C. (2022). Nudibranchs & Sea Slugs of the Eastern Pacific. Molamarine.