OKINAWAN
OPISTHOBRANCH OF THE WEEK
Thecacera picta Baba, 1972 (24 & 22mm)
Opisthobranch of the Week Data
Taxonomy:
- Order: NUDIBRANCHIA
- Suborder: Doridina
- Family: Polyceridae
Frequency on Okinawa:
Collection Data:
- Individual Collection No: RFB #2618-A & #2618-B
- Location: Seragaki (26o 30.4'N, 127o 52.6'E)
- Date: 5 July, 1991 [13 Apr & 19 Aug, '89; 4 Jun & 5 Jul(2), '91;
7 & 26 Jun, 17 Jul, '92; 9 Jan & 15 Mar, '93; 21 Jul, '95]
- Depth: 140ft (42.7m) [130(2), 140(3), 145, 150(2), 160, 170(2)ft]
- Water temperature at collection depth: Not recorded
- Size: TL 24mm & 22mm [13, 13, 16, 17, 22, 22, 23, 24, 25, 29, 38mm]
- Specimen deposited: California Academy of Sciences
[brackets indicate range for all Okinawa-collected specimens of the species]
Species Account:
I consider Thecacera picta to be relatively rare, having collected a total of eleven individuals between April of 1989 and 21 July, 1995. Only one of the eleven was collected from Horseshoe Cliffs; the other ten were collected from Seragaki. In all cases, these attractive little animals were found on the same species of arborescent
bryozoan, locally described as the "Bamboo Bryozoan."
The above illustrated pair of animals were found on the same bryozoan colony during the daytime.
To date there are two other Thecacera spp. found on Okinawa: T. pacifica and T. pennigera, but T. picta is the most common of the three.
Copyright © 1999 Robert F. Bolland
Digitally manipulated photo
