Gymnodoris subflava Baba, 1949

Location: Shibazaki Coast, Hayama, Kanagawa, Japan
Date: 2022/08/21
Length: 10mm
Depth: 0.5m
Water temperature: 23.0℃

Description

A small Gymnodorididae, body length about 1 cm. The whole body, including the rhinophores and gill leaves, is uniformly pale yellow (lemon-coloured). Radula formula about 27×13-16.1.0.1.13-16. The first lateral tooth is distinctive within the genus, being noticeably larger than the rest with a short sickle-shaped cusp; the second and following laterals are short and awl-shaped.

Distribution

Type locality is Hayama-Koiso, Sagami Bay (intertidal, September 1940, 2 specimens). The original description (Baba, 1949) records the species only from Sagami Bay.

Etymology

The specific epithet subflava is Latin for yellowish or pale yellow. The original description does not give an explicit etymology paragraph; the descriptive sense reflects the pale lemon-yellow body colour. The Japanese name "Usuginu-umiushi" (thin-silk sea slug) likens the translucent yellow appearance to thin silk.

Remarks

Distinguished from congeners by the uniformly pale lemon-yellow coloration of the entire body, rhinophores, and gill leaves, and by the larger short-sickle-shaped first lateral tooth. While many Gymnodoris species are known to prey on other nudibranchs, no feeding observation is recorded for this species in Baba 1949.