OKINAWAN
OPISTHOBRANCH OF THE WEEK

Fryeria larryi Brunckhorst, 1993 (3mm)
Photo by Atsushi Ono

Opisthobranch of the Week Data

Taxonomy:

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


Species Account:

        Fryeria larryi is unknown from Okinawa's main island as of mid-December, 2005. The only Fryeria species I've collected from Okinawa's main island, as of the current date, is F. picta. The above featured animal is one which was found on a rock surface at the base of a coral reef in the waters off of Gahi 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 collected by Atsushi Ono during April of 2005 in seven meters of water. Atsushi's photograph is used here with his kind permission. It should be noted that Atsushi considers the species to be very rare in the Kerama Islands as he has seen only the above single featured individual and the specimen was later lost (pers. comm.).

        Brunckhorst (1993) described Fryeria larryi from a single 6mm specimen collected from the waters of Bile Bay, Guam, by Clay Carlson during September of 1973. The following information concerning F. larryi is taken from Brunckhorst (1993):

        External Morphology. Adult size of F. larryi is unknown. The background colour of the dorsum is yellow. There are several (7 on the holotype) isolated, narrow red lines running transversely on the mantle margin. The notal tubercles are minute and rounded, and are evenly distributed over the dorsum. The rhinotubercles are small and similar in shape to the other notal tubercles. The rhinophores possess the same yellow colouration as the dorsum (i.e., not gold). Each rhinophoral clavus possesses 8-10 lamellae. Ventrally, the hyponotum, foot, gills and oral tentacles are yellow and there are no contrasting markings. In the preserved state, the oral tentacles were short and almost square. The posterior, ventral anal opening is large.

        Remarks. Fryeria larryi is distinctive and can be recognised easily by its yellow colouration and the red, transverse markings on the notum. It is the only species of Fryeria with yellow ventral colouration. No other species of Fryeria has yellow gills. The anus in other Fryeria species is small and often difficult to observe without a microscope, but that of F. larryi appears to be large.

        There are similarities between both Fryeria larryi and Phyllidia zebrina. The specimen described by Brunckhorst (1993) had a ventrally positioned anus, suggesting placement into the genus Fryeria; the position of the anus in the Ono specimen isn't apparent in the above featured image, but it may well be there. The Ono specimen appears to have a relatively smooth dorsum, as contrasted with the bumpy surface of Phyllidia zebrina. Both of these species were described from non-dissected, single specimens. This is one of many problems associated with the description and naming of new species from single specimens.

        Bill Rudman has a discussion of Fryeria larryi on the Sea Slug Forum. I've also added a second page with an image of the original holotype specimen, furnished by Clay Carlson and used here with his permission.

Etymology:

Literature Cited:


Page Date: 12 Dec '05
Page Modification Date: 20 Aug '07
Digitally manipulated photo
Copyright © 2007 Robert F. Bolland