Aplysiopsis orientalis (Baba, 1949)

Location: Futou beach, Tago, Futou, Dougashima, Shizuoka, Japan
Date: 2017/12/21
Length: 30mm
Depth: 10.0m
Water temperature: 16.0℃

Description

An aeolid-like sacoglossan, body length about 20 mm. The rhinophores are rather large and ear-shaped with an outer groove, and the tips are bifid. A pair of leaf-shaped oral tentacles is present. The cerata are long fusiform, slightly compressed, with a conspicuous lamellate vein on the inner face and a slight median groove on the outer face; arranged in about 20 oblique rows per side, each row of 2-4 cerata, with branching liver diverticula. The genital orifice lies just behind and below the right rhinophoral angle; the anus on the dorsal midline, slightly to the right, opens at the anterior end of the pericardium. Anterior foot corner rounded. The body ground colour is yellow-white, with the rhinophore tips and oral-tentacle edges blackish, a broad brown longitudinal band running along the dorsal midline from front to tail, and two brown longitudinal bands on the foot. The cerata are blue-green, with only the tips blackish. Lays milky-white egg masses (August 1939).

Distribution

Type locality is Kameshiro-iso, Sagami Bay (11 m depth, August 1940) and off Kurosaki, Sagami Bay (600 m offshore, 15 m depth, August 1939). The original description records the species from Sagami Bay and Okitsu (additional specimen collected by I. Horikoshi, August 1942).

Etymology

The specific epithet orientalis is Latin for of the East. The original description does not give an explicit etymology paragraph; the descriptive sense reflects the eastern (Japanese) provenance.

Remarks

Originally described as Hermaeina (Hermaeina) orientalis and later transferred to Aplysiopsis. Distinguished from the uniformly black sister species Aplysiopsis nigra by the yellow-white ground with brown longitudinal stripes and blue-green cerata.