Opisthobranch of the Week Data
Phyllidia ocellata is considered common throughout the tropical Indo-West Pacific Ocean, including the Red Sea; on Okinawa it's considered to be uncommon. Seventeen specimens have been collected as of early January of 2000, but many additional animals have been seen as well as photographed. This species of Phyllidia is certainly the most striking as well as the most variable of the phyllidiids found on Okinawa. A great deal of variation in both color and pattern is present and as an example of some of this variation, I've included a page consisting of five animals illustrating some of the contrasts in the Okinawan material. Brunckhorst (1993) points out that:
"There is little ontogenetic variation in external pattern (i.e., juveniles resemble adults), however considerable individual variation in dorsal pattern occurs in this species. From the basic pattern described, there appear to be numerous related and irregular patterns where the black areas expand and/or meander across the dorsum (Pls 2D-H, 3A)".
Some variations in color and pattern seen in Phyllidia willani superficially resemble that of some individual P. ocellata, but normally P. ocellata is uniquely identifiable from other family members, even with its variable expressions.
The above featured animal was collected from forty-three meters during a mid-morning SCUBA excursion. The animal was found crawling on a vertical rock wall, festooned with miscellaneous cnidarians, poriferans, and bryozoans.