Cuthona perca (Er. Marcus, 1958)

Description

A small aeolid nudibranch reaching only a few millimetres to about a centimetre in body length. The body is translucent white, and the cerata are filled with an orange-to-brown digestive gland that shows through the wall.

Distribution

Originally described from a coastal lagoon near Cananéia, south-eastern Brazil. Subsequent records are scattered around ports worldwide, especially in less-than-pristine harbour environments — consistent with anthropogenic introduction via hull fouling and similar pathways.

Etymology

The specific epithet perca is Latin for "perch" (the fish), but the original description does not state the rationale for the name.

Remarks

Feeds on sea anemones. Currently held in the genus Cuthona, but recent Trinchesiidae studies (Korshunova et al. 2023) suggest a possible reassignment to Trinchesia.

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References

• Catriona perca n. sp., Marcus Er. (1958). On western Atlantic opisthobranchiate gastropods. American Museum Novitates. 1906: 1-82.
• IWASAKI K., KIMURA T., KINOSHITA K., YAMAGUCHI T., NISHIKAWA T., NISHI E., YAMANISHI R., HAYASHI I., OKOSHI K., KOSUGE T., SUZUKI T., HENMI Y., FUROTA T. & MUKAI H. (2004). Human-mediated Introduction and Dispersal of Marine Organisms in Japan: Results of a Questionnaire Survey by the Committee for the Preservation of the Natural Environment, the Japanese Association of Benthology. Japanese journal of benthology. 59: 22-44. https://doi.org/10.5179/benthos.59.22
• コウワンミノウミウシ（新称）, 柏尾翔 & 田中広樹. (2021). 外来種ミノウミウシ Trinchesia perca (Er. Marcus, 1958) の形態・生態学的知見, および日本国内における分布について. ちりぼたん. 52(1): 30-43.