Opisthobranch of the Week Data
Dendrodoris elongata is considered to be rare on Okinawa as I have collected only seven individuals; the first specimen was collected on 30 April, 1987 and the most recent animal was discovered on 19 June, 1992. The above featured animal was found beneath a slab of coral rubble as it was overturned; it was located within several centimeters of an additional individual (43mm). As do other members of the species, D. elongata has a decidedly soft and gelatinous-feeling body. The gills of D. elongata are located near the extreme end of the body. Most dendrodorids are sponge predators and there is no reason to suspect that this species feeds otherwise, although the seven Okinawan-collected animals were not found associated with any potential prey.
Baba (1936) described the animal from a single 60mm specimen collected on 26 July, 1934 from Ishigaki-shima (approximately 400km SW of Okinawa). Baba (1994) more recently describes the anatomy in greater detail. Baba's original description of external morphology fits the local Okinawan specimens quite nicely as follows:
"The ground colour of the back is a pale dirty yellow, becoming darker towards the middle, and is closely covered with dark brown mottles of various size. The perforations of the rhinophores are are dark olive and the branchial plumes are stained with pale brown inside. The underside of the body uniformly dirty yellow."
Wells & Bryce (1993, p. 141, fig. 184) feel that Dendrodoris elongata is a junior synonym of D. albobrunnea. However, the dorsum of D. elongata is relatively smooth (having small subconical granules) whereas D. albobrunnea [= D. albopurpura] has distinctive conical warts all over the dorsum. I've photographed a single specimen of D. albopurpura here, but the slides are so dark that they defy my ability to scan them into reasonable images. See Atsushi Ono's photograph of D. albopurpura.