OKINAWAN
OPISTHOBRANCH OF THE WEEK

Hancockia burni Thompson, 1972 (13mm)
Photo by Atsushi Ono

Opisthobranch of the Week Data

Taxonomy:

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


Species Account:

        Species of Hancockia are often found on brown laminarian algae and kelp, where they are well camouflaged and feed on hydroids growing on the algae. H. burni is the only member of the genus described from the Indo-West Pacific, specifically from eastern Australia, and it ranges from a pale translucent brown to a dark brown with white patching (Rudman, 2001). Additionally, there are photographs of H. burni in both Coleman (2001, p. 98) and Debelius (1996, p. 285).

        I've not personally seen nor collected any specimens of H. burni and it is unknown from Okinawa Island at the current time (early September, 2001), but it has been photographed by Atsushi Ono in the Kerama Islands. The close proximity of the main island of Okinawa to the Kerama Islands, as well as the similar opisthofauna to that of the Kerama Islands, suggests the possibility that it is also present here on Okinawa proper. The above featured animal is one which was found and photographed on dead coral in four meters of water off Amuro Island, one of a series of islands in the Kerama Islands Group, which are located 30 ~ 40 kilometers west of the Okinawa capitol, Naha. This featured animal was photographed by Atsushi Ono and his photograph is used here with his kind permission; the species is considered to be very rare in Okinawan waters and Atsushi mentions this is the only individual he has seen in the Kerama Islands (Ono, per. comm.).

Literature Cited:


Page Date: 03 Sep '01
Page Modification Date: 03 Sep '01
Digitally manipulated photo
Copyright © 2001 Robert F. Bolland