Thordisa luteola J. M. Chan & Gosliner, 2007

Location: Tengan(Kombu), Okinawa Island (East coast), Okinawa, Japan
Date: 2016/05/30
Length: 20mm
Depth: 5.0m
Water temperature: 24.5℃

Description

Reaches 30 mm in length, with an oval, low-profile body. The most diagnostic feature is the bright lemon-yellow mantle, the source of the species name. The dorsum bears tan, transparent papillae and rounded tubercles dispersed evenly throughout, with the papillae having a wide base from which long filamentous extensions emerge and branch two to five times near the base or along the sides. Rhinophores are perfoliate with 10–12 lamellae and the rhinophoral sheath is covered with tubercles. The gill is completely retractile, tripinnate, with six branches; the short gill sheath is also covered with tubercles. Brown spots are dispersed randomly across the dorsum; rhinophores and gill are dark brown. Living animals are encrusted with sand particles.

Distribution

Type locality: Jesser Point, Sodwana Bay National Park, South Africa, intertidal zone (Holotype SAM A35376, 7 May 1982). At the time of the original description (Chan & Gosliner, 2007) the species was only known from South Africa.

Etymology

From the Latin word luteolus ("yellow"). The original description (Chan & Gosliner, 2007) states that the name was given to describe the bright yellow mantle colour of the new species.

Remarks

One of the five new species described by Chan & Gosliner 2007. The specimen previously figured as Thordisa sp. 2 in Gosliner 1987 Nudibranchs of Southern Africa belongs to this species. Thordisa amakusana Baba, 1937 (from Amakusa, Japan) also has a yellow mantle, but is distinguished by minute chocolate-coloured spots on the dorsum, unipinnate gills, and a smooth rhinophoral sheath.