Opisthobranch of the Week Data
Elysia rufescens is considered to be very rare on Okinawa as I have seen and collected only the single above featured animal as of early-April, 2002. This animal was collected in early September of 1991 from a live stony coral reef during a daytime spring tide SCUBA excursion. Atsushi Ono reports (per. comm.) seeing only two individuals in the Kerama Islands Group and therefore considers it to be rare there as well. I've added a second page with a single photograph of one of Atsushi's Kerama Islands animals and the image is used here with his kind permission.
I don't have access to the original species description (Pease, 1871) and have therefore taken the liberty to use the following description found in Kay (1979) based on Hawaiian material:
Length, 11 mm; parapodial height, 3mm. Animal: parapodia low but erect, with two or three undulations; rhinophores long and slender, directed anteriorly; pericardial prominence a white sac at the anterior end of the parapodia. Color: dark red maculated with spots of creamy green which impart a reticulated appearance to the animal; parapodia margined with orange; rhinophores dark red tipped with purple.
Specimens have been collected at various times during the year; the animals are usually found on the sides of rocks in shallow waters shoreward of fringing reefs.
Also, Rudman (1999) has posted on the Sea Slug Forum one of the original plates taken from Pease's description of the species.
In addition to the above featured Elysia rufescens, the following Elysia have been previously featured on these pages:
E. amakusana E. cf. bennettae E. lobata E. mercieri E. obtusa E. ornata E. thompsoni E. cf. tomentosa E. yaeyamana