Ceratosoma gracillimum Semper in Bergh, 1876 (70mm)

Opisthobranch of the Week Data


Frequency on Okinawa:
Collection Data:
[brackets indicate range for all Okinawa-collected specimens of the species]

Species Account:

        Ceratosoma gracillimum is considered to be very rare on Okinawa as I have seen and collected only a single individual. The above featured animal was found and collected beneath the pier from a vertical concrete support piling; the animal was found approximately a meter and a half from a silty-sand bottom, covered with strewn oyster shell rubble. The piling from which the animal was collected was covered with a large array of miscellaneous free-standing and encrusting invertebrates (bryozoans, cnidarians, pelecypods, poriferans), as well as relatively large numbers of urochordates. The Ceratosoma most apt to be confused with C. gracillimum is C. trilobatum, however, C. trilobatum has an obvious mantle rim between the head and lateral body extensions.

        Ceratosoma gracillimum has a tropical Indo-Pacific distribution.

        As of this writing (April, 2001) C. gracillimum is one of seven species of Ceratosoma known from Okinawa. The seven species identified to date are:

Page Date: 25 Dec '00
Page Modification Date: 30 Apr '01
Digitally manipulated photo
Copyright © 2001 Robert F. Bolland