OKINAWAN
OPISTHOBRANCH OF THE WEEK

Phyllidia larryi (Brunckhorst, 1993) / 5mm
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:

        This attractive little Phyllidiid, Phyllidia larryi, is unknown from Okinawa's main island as of mid-February, 2012. The above featured animal is one which was photographed from rock of a coral reef environment off 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 photographed by Atsushi Ono during February of 2010 in six meters of water. Atsushi's photographs are 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 three individuals, all from Gahi Island waters (pers. comm.). I've added a second page w/ three additional images of P. larryi (a second photo of the same animal as above, and photos of a second and third animal) from the Kerama Islands, all photographed by Atsushi.

        The following information on external morphology and remarks is taken from the original description of Phyllidia larryi (as Fryeria larryi) by 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 very small and often difficult to observe without a microscope, but that of F. larryi appears to be large.
The only other Fryeria species which does not possess black pigmentation is F. bayi. Fryeria bayi is also a small species, but it is cream-white in colour with a brownish mottled pattern, and it has white rhinophores with three very oblique lamellae. These features clearly separate F. bayi from F. larryi. Phyllidia zebrina is superficially similar to the present species, however it possesses a pale cream colouration with brownish markings, larger tubercles (minute in Fryeria larryi) and a dorsal anus.

        There is apparently a bit of confusion in some of the literature as to the correct species name of this little Phyllidiid. In addition to the original name given by Brunckhorst (1993), two names have been applied, Phyllidia larryi and P. zebrina. Both descriptions of these two animals were based on a single specimen, so of course nothing is known of variation within the species. Current workers refer to the species as Phyllidia larryi (Gosliner, T.M., D.W. Behrens, & A. Valdes, 2008) and not P. zebrina. Originally it was thought that this was in the genus Fryeria, but it's currently considered to be a Phyllidia.

        See the Sea Slug Forum for a discussion and image of Phyllidia larryi (as Fryeria larryi) as well as comments on Phyllidia zebrina or Fryeria larryi. In addition, there are several images of Phyllidia larryi on the Umiushi-zukan.com site from Kagoshima (Japan's southern island of Kyushu) and Okinawa.

        The following Phyllidia species have been previously featured on these pages:

Etymology:

Literature Cited:


Page Date: 20 Feb '12
Page Modification Date: 20 Feb '12
Digitally manipulated photo
Copyright © 2012 Robert F. Bolland