Opisthobranch of the Week Data
Dendrodoris coronata is considered to be very rare in Okinawan waters; only three individuals have been seen by Atsushi (per. comm.) and RFB has seen none directly off Okinawa's main island. The above featured animal was photographed and collected, from Gahi Island, in the Kerama Islands, one of a series of islands in the Kerama Islands Group, which are located 30 ~ 40 kilometers west of the Okinawa Capitol, Naha. This featured animal was found on the underside of a rock by Atsushi Ono during October of 1998 in 3m of water. Atsushi's photograph is used here with his kind permission.
Dendrodoris coronata is remarkably similar in appearance to some prosobranch cowries (Cypraea spp. of the Family Cypraeidae). The following account of external morphology of D. coronata is taken from the species description by Kay & Young (1969):
DESCRIPTION: Length, 8 to 30 mm; width, 4 to 17 mm. The animal is broadly oval, wider posteriorly than anteriorly, soft, convex above, and the mantle margins are very thin and undulated. The mantle is transparent white, peppered with black and flaked with white; it is ornamented with numerous but irregular scattered pustules, those immediately anterior to the branchiae crownlike on a transverse raised ridge. The rhinophores are long and slender, with about 12 lamellae; they are fawn, peppered with black. The branchiae are large and feathery; they are fawn as are the rhinophores. The ventral surface of the foot is white. There is a pair of auriculate cephalic tentacles which border the porelike mouth.
The holotype is 20 mm in length, 10 mm in width. The holotype and a paratype have been deposited in the B. P. Bishop Museum, and paratypes in the U. S. National Museum, Washington, D.C.
The species is named for the middorsal crown of tubercles on the mantle; the crownlike arrangement of the tubercles consistently distinguishes this species from other pustulate dendrodorids.
Tomohiko Kurihara has several photographs of D. coronata from Osezaki (at the NE side of Izu Peninsula), Japan, on his nudibranch site. This is the only individual seen by Tomohiko; he photographed the 12mm animal in December of 2002 from one meter.
There are eight described species of Dendrodoris known from Okinawan waters as of early-May, 2003). These eight species are:
D. albopurpura D. carbunculosa D. coronata (the above featured animal) D. denisoni D. elongata D. fumata D. nigra D. tuberculosa