Cadlinella subornatissima Baba, 1996

Location: Ishikiri（Awa), Okinawa Island (Motobu and Northern area), Okinawa, Japan
Date: 2013/04/11
Length: 10mm
Depth: 10.0m
Water temperature: 22.0℃

Description

Body reaches about 10–30 mm in life. On a translucent white ground colour, a broad yellow longitudinal band runs along the centre of the mantle. The yellow pigment stops short of the mantle margin and does not extend to the base of each papilla, so each papilla sits in a translucent patch surrounded by a thin white border. The dorsum bears tall, club-shaped white papillae, the tips of which are often faintly tinged with pink. Marginal papillae are shorter, smaller and yellowish white. Rhinophores are white and long; the gill plumes are also white. Mantle glands are restricted to small, scattered single glands near the mantle edge, in contrast with Cadlinella ornatissima, which carries several gland types arranged in distinct bands.

Distribution

Described from Japan and recorded from southern Korea and the Marshall Islands, indicating a western Pacific distribution. Specimens have been observed mostly between 5 and 10 m on coral-reef slopes, under dead coral on rubble and sand, and in inner-bay rocky habitats.

Etymology

The specific epithet subornatissima combines the Latin prefix sub- ("nearly, almost") with ornatissima ("most ornately decorated"), the epithet of the type species Cadlinella ornatissima. The name therefore signals that the new species closely resembles C. ornatissima but is taxonomically distinct. The Japanese vernacular name "ニセイガグリウミウシ" (literally "false sea-chestnut sea slug") reflects the same idea — that it is a look-alike of the well-known イガグリウミウシ (C. ornatissima).

Remarks

Externally very similar to, and sometimes sympatric with, Cadlinella ornatissima. The two are distinguished externally by (1) the restriction of yellow pigment to a median band in C. subornatissima versus a more extensively yellow dorsum in C. ornatissima, (2) the taller, club-shaped papillae of C. subornatissima, often only faintly pink-tipped rather than strongly pink-tipped as in C. ornatissima, and (3) the simpler arrangement of mantle glands (scattered single glands at the margin only, versus several gland types in bands). The two have occasionally been treated as a single species, but they are currently regarded as distinct (WoRMS).