OKINAWAN
OPISTHOBRANCH OF THE WEEK
Ceratosoma tenue Abraham, 1876 (65mm)
Opisthobranch of the Week Data
Taxonomy:
- Order: NUDIBRANCHIA
- Suborder: Doridina
- Family: Chromodorididae
Frequency on Okinawa:
Collection Data:
- Individual Collection No: RFB #1812-A
- Location: Horseshoe Cliffs, Okinawa (26o30.0'N, 127o50.9'E) [Horseshoe Cliffs, Seragaki]
- Date: 11 April, 1987 [Apr '87, May '87, Jun '88, Jul '89, Oct '90, Jun '92,
Feb '93, Apr '93, May '97]
- Depth: 150ft (45.7m) [130ft, 140ft, 150ft, 155ft, 160ft, 170ft, 175ft, 180ft,
220ft]
- Water temperature at collection depth: 72.0oF (22.2oC)
- Size: TL 65mm [37mm, 60mm, 63mm, 65mm, 70mm, 72mm, 73mm, 98mm, one indiv. not
measured]
- Specimen deposited: RFB Personal Research Collection (different individuals
of the species deposited at Cal Acad Sci)
[brackets indicate range for all Okinawa-collected specimens of the species]
Species Account:
Ceratosoma tenue is considered to be uncommon on Okinawa;
I've collected nine individuals to date, but I've seen and/or photographed perhaps an
additional two or three others which were not collected.
Another similar appearing species of Ceratosoma found
here is C. trilobatum, which is found in roughly the same
frequency (remarkably, I've collected the same number of both species, nine), although my
experience has been to find it on Okinawa more commonly in shallower waters than
C. tenue. The prominent median horn rising posterior of the gills on both Okinawan
species produces similar appearing animals but they are usually quite readily separated from
each other by the single pair of prominent lateral projections located near the gills of
C. trilobatum; in the case of C. tenue there are two sets of lateral projections.
Both of the species seem to exhibit quite a bit of color variation.
Page Date: 28 Sep '98
Page Modification Date: 30 Apr '01
Digitally manipulated photo
Copyright © 2001 Robert F. Bolland