Catriona pinnifera (Baba, 1949)

Location: Gontarou Rock, Hayama, Kanagawa, Japan
Date: 2005/05/05
Length: 15mm
Depth: 3.0m
Water temperature: ??℃

Description

A small Aeolidacea, body length 7-10 mm. The rhinophores are very long, with 5-8 fine semi-ring (winglet-like) lamellae along their entire length — a key diagnostic feature. Cerata in 8-9 oblique rows per side: 1st row 3, 2nd-5th 4 each, 6th 3, 7th onward 1-2 each. Right (and left) liver branches into 3 oblique rows. The genital orifice opens directly below the 2nd row on the right side; the anus opens just before the inner end of the 4th row; the nephroproct directly in front of the anus. Anterior foot corners rounded. The body is white; the oral tentacles bear a single yellow ring at mid-length. The cerata have albuminous white tips, with a wide yellow ring just below the tip; the central vein is green to brown. The masticatory edge of the jaw plate bears a single row of 20-22 denticles. Radula formula 45×0.1.0. The central tooth bears 6-7 denticles on each side of the median cusp.

Distribution

Type locality is Hayama-Koiso, Sagami Bay (intertidal, August-September 1940, 19 specimens). The original description (Baba, 1949) records the species only from the type locality.

Etymology

The specific epithet pinnifera is a Latin compound of pinna (wing/feather) and ferre (to bear), meaning "wing-bearing". The original description does not give an explicit etymology paragraph; the descriptive sense reflects the semi-ring (winglet-like) lamellae on the rhinophores. The Japanese name "Tsuno-bane-mino-umiushi" (winged-horn aeolid) likewise refers to the lamellae.

Remarks

Originally described as Cratena (Catriona) pinnifera and later transferred to Catriona. Distinguished from Cratena venusta (described in the same monograph) by (1) the winglet-like lamellae on the rhinophores (versus simple in Cratena venusta) and (2) the white ground with a yellow ring (versus the orange-yellow ground with a red-purple central vein in Cratena venusta).