OKINAWAN
OPISTHOBRANCH OF THE WEEK

Thecacera pacifica (Bergh, 1883) 21mm

Opisthobranch of the Week Data

Taxonomy:

Order: NUDIBRANCHIA
Suborder: Doridina
Family: Polyceridae

Frequency on Okinawa:

Very rare

Collection Data:

Individual Collection No: RFB #3437-B
Location: Tengan Pier, Okinawa (26^o24.0'N, 127^o51.1'E)
Date: 25 June, 1995 [Only a single specimen collected to date]
Depth: 40ft (12.2m) [Only a single specimen collected to date]
Water temperature at collection depth: 71.4^oF (21.9^oC)
Size: TL 21mm [Only a single specimen collected to date]
Specimen deposited: California Academy of Sciences

[brackets indicate range for all Okinawa-collected specimens of the species]

Species Account:

Thecacera pacifica is considered to be very rare on Okinawa as I have seen and collected only a solitary individual over a period of a good many year of diving here. This attractive little polycerid was found during a daytime SCUBA excursion at approximately 09:00am beneath the concrete pilings of a large concrete pier. The animal was found crawling in the open on the bottom amid mixed strewn oyster shell rubble and silty sand.

I've found to date, in addition to the featured Thecacera pacifica, two other Thecacera spp. here on Okinawa, T. pennigera and T. picta.

OKINAWANOPISTHOBRANCH OF THE WEEK

OKINAWAN
OPISTHOBRANCH OF THE WEEK