OKINAWAN
OPISTHOBRANCH OF THE WEEK

Chromodoris lochi Rudman, 1982 (25mm)
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:

        Chromodoris lochi is currently unknown from Okinawa's main Island as of early-April, 2002. 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 photographed in the waters of Zamami Island, one of a series of islands in the Kerama Islands Group, which are located 30 ~ 40 kilometers west of the Okinawa capitol, Naha. The featured animal was photographed by Atsushi Ono during July of 1998, on a rock of a cliff wall in 25m of water. Atsushi's photograph is used here with his kind permission and he considers the species to be rare; Atsushi reports (per. comm.) seeing approximately five individuals in the Keramas.

        The only other chromodorid found on Okinawa which could be confused with C. lochi is C. willani. The distinctive tiny white opaque spots on both the gills and rhinophore clubs of C. willani clearly distinguish the two from each other. Another similar-appearing species found here is C. boucheti, but that species differs in having secondary black lines on the mantle and the basal half of the gills is white and the upper half is yellow.

        The following partial description of Chromodoris lochi is taken from Rudman (1982):

        Colour: The mantle varies in colour from white to pale bluish white in different specimens, with a thin white border. A thin black line runs around the anterior end of the mantle, in front of the rhinophores, and down each side joining behind the gills. There is another black line down the midline from just in front of the rhinophores back to the gill pocket. This median line is often broken and can sometimes be reduced to a small dash between the rhinophores and another just in front of the gills. The black lines can be of variable width and often there is a diffusion of bluish black pigment into the white on either side of the line. The gills and rhinophores are a pale watery yellow or orange.
        The sides of the body and the foot are of similar colour to the mantle. There can be up to tree thin black lines along the sides of the body, the lower one on each side extending back on to the dorsal surface of the posterior foot.
        Shape: The body is elongate with a relatively narrow mantle overlap along the sides giving the animal a spatulate shape. As described earlier (Rudman, 1977) the gills are simple in structure, arranged in a circle open posterior, and are held vertically in the living animal. This species has only a small number of gills seldom exceeding five or six.

        The name was chosen by Rudman in honor of Mr. Ian Loch, Technical Officer in the Malacology Department of The Australian Museum, who collected and photographed large collections of opisthobranchs for the Museum, while living in Queensland.

Literature Cited:


Page Date: 08 Apr '02
Page Modification Date: 08 Apr '02
Digitally manipulated photo
Copyright © 2002 Robert F. Bolland