Ceratodoris pilosa (Bouchet & Ortea, 1983)

Location: Wannai, Osezaki, Shizuoka, Japan
Date: 2018/01/29
Length: 15mm
Depth: 1.0m
Water temperature: 13.0℃

Description

The body is broad and ovoid, lacking a distinct notal border. The foot is short and does not extend beyond the oval of the general body. Body color is uniformly translucent white, with a network of opaque white and yellow pigment on the notum and rhinophores; scattered brown spots are also present on the notum. The gill rachises are translucent yellow. There are 35–40 elongate papillae scattered over the dorsal surface of the body, with a single mid-dorsal papilla immediately anterior to the gill. The gill consists of 12 bipinnate branches. The rhinophores are relatively short with 7–8 congested lamellae. The anterior end of the foot is deeply indented anteriorly, forming a V-shaped edge that encloses the mouth. Radular formula 19 × 1.1.0.1.1. Body length about 11 mm.

Distribution

Originally described from New Caledonia (Bouchet & Ortea 1983). Additional records from Hong Kong (Rudman & Darvell 1990) and Papua New Guinea (Madang). Also recorded from Japan (Honshu).

Etymology

From Latin pilosus (hairy), referring to the numerous elongate papillae scattered over the notum.

Remarks

Found under coral rubble at about 6 m depth. Externally similar to Ceratodoris plana, with a translucent body color and mottled brown spots that render living animals exceedingly cryptic on their host bryozoans. The original genus Hopkinsia was synonymized with Okenia; the subsequent transfer to Ceratodoris follows post-2004 phylogenetic work.