Verconia subnivalis (Baba, 1987)

Location: Kyoto, Japan
Date: 2017/08/26
Length: 22mm
Depth: 1.0m
Water temperature: 27.0℃

Description

A small Chromodorididae, body length 15-20 mm alive. Back pure snow white, without any sign of yellow or orange-yellow spots — a key diagnostic difference from the sister species Verconia nivalis. The mantle margin has a double border: orange-yellow on the outside and yellow on the inside (V. nivalis has only a single yellow line). The mantle glands inside the mantle margin are opaque white. Rhinophores reddish purple above (V. nivalis has orange-yellow / vermilion clubs) and colourless below. Branchial plumes 10-12, simply pinnate, almost entirely pure white (occasional individuals show a single yellow-tipped plume). Underside pure white. The dorsum bears scattered minute conical tubercles.

Distribution

Type locality: Ogi, Toyama Bay, Japan. Type-series localities also at Fukuura on the west coast of the Noto Peninsula and along the Echizen Coast.

Etymology

The specific epithet subnivalis is a Latin compound of sub- (near, similar to) and nivalis (snowy), meaning "near-snowy" or "resembling nivalis". The Japanese name "Shirayuki-modoki" (literally "false snow-white") parallels the Latin construction directly, with "modoki" ("resembling / mimicking") corresponding to sub-.

Remarks

Originally described as Noumea subnivalis. Noumea was subsequently sunk into Verconia, giving the current combination. Distinguished from V. nivalis by five characters: (1) absence of yellow / orange-yellow spots on the back, (2) the double mantle border (orange-yellow outside, yellow inside), (3) reddish-purple rhinophore clubs, (4) white branchial plumes, and (5) details of the first lateral radular tooth.