OKINAWAN
OPISTHOBRANCH OF THE WEEK

Lobiger viridis Pease, 1863 (22mm)
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:

        There is currently a great deal of confusion concerning the species placement of Lobiger viridis. Some current literature favors the use of L. souverbii (Marshall & Willan, 1999) but others prefer the use of L. viridis (Ono, 1999; Rudman, 2001). In the Sea Slug Forum, Rudman (2001) mentions, in part, the following:

The degree of secondary branching of the parapodial flaps is quite variable. Certainly in juveniles the secondary branches appear just as 'buds' along the edge of the parapodial flap. These animals often drop and regrow the parapodial flaps. It is possible that regrown flaps do not have as extensive branching as the original flaps. We have much still to learn about these animals. Clearly the radula of Lobiger viridis needs to be re-examined, but in the mean time I think we may as well use that name for all Indo-West Pacific Lobiger.
I've decided to defer to the opinions of both Dave Behrens (per. comm.) and Rudman (2001) in using the name L. viridis.

        The following description of Lobiger viridis is taken from Marshall & Willan (1999) [as L. souverbii p. 30].

The body of this moderately large sacoglossan is too large to fit inside its thin, ear-like shell. The animal has a short broad tail. The rhinophores are long and pustulose. The parapodia are represented by four, curled lobes whose edges are deeply crenulated.
The mantle is vivid green and often, but not always, has several, thin, dark longitudinal lines which are plainly visible through the transparent shell. The exterior of the lateral lobes is green and pustulose in contrast to the interior which is smooth and vivid orange.
The lobes can be cast off (autotomised) when the animal is irritated.
The presence of the parapodial lobes immediately renders Lobiger souverbii distinct from all other sacoglossans.
Lobiger souverbii lives only on the green alga Caulerpa sp. (family Caulerpaceae) which it resembles greatly. The spawn is unknown.

        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 and collected by Atsushi Ono during January of 1999, from a buoy line in 15m of water. Atsushi's photograph is used here with his kind permission and he considers the species to be uncommon in the Kerama Islands; Atsushi reports (per. comm.) seeing in excess of ten individuals in the Keramas, but only a single individual has been collected ( two additional Keramas animals of the species were photographed but not collected). Ichikawa (1993) reports two animals (as L. souverbii), 1cm && 3cm, from Aka Island, also in the Keramas.

Literature Cited:


Page Date: 11 Feb '02
Page Modification Date: 11 Feb '02
Digitally manipulated photo
Copyright © 2002 Robert F. Bolland