OKINAWAN
OPISTHOBRANCH OF THE WEEK

Polycera abei (Baba,1960) 17mm
Photo by Atsushi Ono

Opisthobranch of the Week Data

Taxonomy:

Frequency on Okinawa: Collection Data:
[brackets indicate range for all Okinawa-collected specimens of the species]


Species Account:

        Polycera abei was originally described [as Greilada abei] from several sites in Japan by Baba (1960). In addition to the original Japanese collection sites, P. abei is also reported in the Sea Slug Forum (Rudman, 2001) as being found in Hong Kong and eastern Australia.

        The following is from Baba's original species description:

        Length about 15mm. Body limaciform, smooth above (non-tuberculate), no pallial ridge on each side. Velar papillae 6, long and digitiform. Rhinophores perfoliate, non-retractile. Branchial plumes 7, simply pinnate, non-retractile; no exo-branchial appendage on each side of the gill. Oral veil semicircular; foot-corners angulated. General body-colour translucent yellowish white, the above with black spots interspersed among the orange ones. Rhinophores and velar papillae black; gills yellowish white with black tips; sole without markings.
        Polycera abei is considered to be rare in Okinawan waters; I've not personally seen this attractive little polycerid in waters of Okinawa's main island and Atsushi Ono reports the above featured animal is the only one he has seen (pers. comm.). The animal was collected by Atsushi in February of 1998 beneath dead coral from the south area of Gahi Island, Kerama Islands Group, which are located 30 ~ 40 kilometers west of the Okinawa capitol, Naha.

        As of late October, 2001, the only other similar appearing polycerid collected from Okinawa's main island is Crimora lutea, but on inspection the small black papillae, irregularly scattered over the notum and tail of C. lutea, are quite unlike the black spots of P. abei.

Literature Cited:


Page Date: 29 Oct '01
Page Modification Date: 29 Nov '01
Digitally manipulated photo
Copyright © 2001 Robert F. Bolland