OKINAWAN
OPISTHOBRANCH OF THE WEEK

Phyllidiella granulata Brunckhorst, 1993 (41mm)

Opisthobranch of the Week Data

Taxonomy:

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


Species Account:

        Phyllidiella granulata is considered to be rare in Okinawan waters as the above featured animal is the only specimen I've collected. However, Three additional animals have been photographed but not collected from the main island of Okinawa. Atsushi Ono (1999) has found this species in the Kerama Islands and he reports (pers. comm.) seeing eight individuals in the Kerama Islands, but only a single specimen has been collected by Atsushi as well.

        There are two species of similar appearing phyllidiids found here: Phyllidiopsis pipeki and Phyllidiella rudmani, but the relatively large white-tipped pink tubercles of Phyllidiopsis pipeki (the tubercles are white and not pink in Phyllidiella granulata) and the pink & black banded rhinophores of P. rudmani (black in P. granulata) distinguish the three from each other, at least in external characters.

        The following description of external morphology of P. granulata is taken from Brunckhorst (1993):

        Live specimens ranged in size from 11-40 mm and mean size was 26 mm. Phyllidiella granulatus [the accepted spelling of this animal is now P. granulata {rfb}] is oval in shape. Its background colouration is granular, gray (to pale gray). Medially, three encircling irregular black bands partition the pale background colour into two or three large patches. The black bands extend in front of the rhinophores, and behind the anal opening. White tubercles arise from the pale notal areas. The tubercles are conical and usually occur singly. The median tubercles are tall, acute and may be compound. The dorsal pattern was similar throughout the size range studied. The black rhinophores are slightly recurved posteriorly and pointed apically. Each rhinophoral clavus possesses 17-20 broad lamellae (specimens greater than 20 mm).         Ventrally, the hyponotum is grey. The gills are dark grey. The foot sole is pale gray with granular white dots. The oral tentacles are conical, pointed apically, white ventrally, and black-tipped dorsally.

Etymology:

Literature Cited:


Page Date: 22 Apr '02
Page Modification Date: 22 Apr '02
Digitally manipulated photo
Copyright © 2002 Robert F. Bolland