Cuthona hermitophila Martynov, Sanamyan & Korshunova, 2015

Description

A small aeolid nudibranch closely resembling the sibling species Cuthona nana. Holotype body length about 10 mm. Body relatively broad, with a weakly developed tail. Cerata are arranged in up to 15 rows of 5-9 each; cerata elongate and finger-shaped. Foot relatively broad, with a straight anterior margin; head fairly broad and rounded. Oral tentacles arise from the dorsal surface of the head, conical. Rhinophores smooth, conical. The genital opening is below the 2nd-3rd rows of cerata. Radula formula 15 × 0.1.0, with 5-8 lateral denticles flanking the cusp of the central tooth. Body pale yellowish-white; cerata white with brown speckling.

Distribution

Northwestern Pacific. Type locality: Kievka Bay, Sea of Japan, Russian Far East, 2-3 m, collected from the siphonal extension of a Neptunea bulbacea shell occupied by the hermit crab Pagurus ochotensis. Paratypes from the Bering Sea. Also recorded from Rausu, Hokkaido, Japan. The original description gives the range as the Far Eastern seas of Russia (Sea of Japan, Bering Sea), with possible occurrence near the Commander Islands.

Etymology

The specific epithet hermitophila combines Latin hermit ("hermit crab") and philus ("loving"), reflecting the species' close association with hermit crabs. The Japanese common name "Raus-mino-umiushi" refers to Rausu, Hokkaido, where the species has been recorded.

Remarks

A member of the family Cuthonidae. Distinguished from the Atlantic Cuthona nana and the Pacific Cuthona divae by the number and arrangement of dorsal papillae. The genus Cuthona has undergone extensive taxonomic revision, with most species transferred to other genera; C. hermitophila remains in Cuthona together with the type species C. nana and C. divae.

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References

• Cuthona hermitophila n.sp., Martynov A.V., Sanamyan N.P., Korshunova T. A. (2015). [in Russian] New data on the opisthobranch molluscs (Gastropoda: Opisthobranchia) of waters of Commander Islands and Far-Eastern seas of Russia. In: Conservation of biodiversity of Kamchatka and coastal waters. Proceedings of XV international scientific conference Petropavlovsk-Kamchatsky. Kamchat Press: Petropavlovsk-Kamchatsky, Russia. pp. 55-69, pl. 2-6.