Chlamylla borealis orientalis (Volodchenko, 1941)

Description

A small aeolid nudibranch reaching about 15 mm in body length. The body is semi-transparent whitish to pale orange, with numerous slender cerata along the dorsum. As a member of the genus Chlamylla, it possesses a distinctive complex folded penial collar in the reproductive system.

Distribution

Northern to western Sea of Japan, including the coasts of northern Japan and the Russian Far East. The type locality is Vostok Bay within Peter the Great Bay, Primorsky Krai, Russia. The subspecies is locally abundant during winter.

Etymology

The subspecific epithet orientalis is Latin for "eastern", reflecting that this subspecies was described from the eastern (Sea of Japan) range, in contrast to the nominate subspecies known from arctic waters. The specific epithet borealis is Latin for "northern".

Remarks

A member of the family Paracoryphellidae. Originally described as Coryphella orientalis in 1941, it was later treated as a subspecies of Chlamylla borealis. Some authors consider it a junior synonym of Chlamylla atypica, but WoRMS currently recognizes it as a valid subspecies. The family Paracoryphellidae was reinstated by a 2017 revision from the previously broader Flabellinidae (ZooKeys 717: 1-139).

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References

• Japanese name: Kabuto-minoumiushi, new, Yoshiaki J. Hirano (1997). A Record of Chlamylla atypica (Bergh, 1899) (Gastropoda : Nudibranchia) from Japan. Species Diversity. 2(1): 83-91. https://doi.org/10.12782/specdiv.2.83
• Chlamylla borealis orientalis (Volodchenko, 1941), comb. n., Korshunova T., Martynov A., Bakken T., Evertsen J., Fletcher K., Mudianta I.W., Saito H., Lundin K., Schrödl M. & Picton B. (2017). Polyphyly of the traditional family Flabellinidae affects a major group of Nudibranchia: aeolidacean taxonomic reassessment with descriptions of several new families, genera, and species (Mollusca, Gastropoda). ZooKeys. 717: 1-139. https://doi.org/10.3897/zookeys.717.21885