OKINAWAN
OPISTHOBRANCH OF THE WEEK

Vayssierea felis (Collingwood, 1881) 3mm
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:

        Vayssierea felis is considered to be uncommon in Okinawan waters; I've not personally collected any specimens from Okinawa's main island and Atsushi Ono mentions (pers. comm.) seeing 5 or 6 individuals in the Keramas.* The above featured animal was found and photographed by Atsushi in intertidal waters from beneath a rock. Atsushi's photo shows the tests of several annelid (Spirorbis sp.) worms upon which Vayssierea felis is known to feed (Rudman, 2000).

        Jun Imamoto (2004) has a large photo series of Vayssierea felis from Japanese waters on his Sea Slug Site. Jun's photos show some of the color variation seen in the Japanese material, including ova within the gonads as well as ova deposited on several substrata.

        Bill Rudman (2000) reporting in the Sea Slug Forum points out the following information concerning life history and anatomy of this little dorid. I've taken the following information from the discussion of Vayssierea felis on the Sea Slug Forum:

Collingwood first described this species from the South China Sea. Because of its small size and lack of gills he considered it to be most probably a juvenile of a species of Gymnodoris (Trevelyana). He found specimens in tide pools and described it as `very active and flexible, assuming at different times the most singular of forms, resembling in turn a fox, a rabbit, a cat, according to its different attitudes.' Although no internal anatomy was described, the size, colour, lack of gills, simple rhinophores and rapid movement and flexibility, clearly characterise this species which has been found, under various names in many parts of the Indo-West Pacific. Collingwood queries whether his species is a juvenile of the earlier named gymnodorid Stenodoris rubra Pease, 1866. Vayssierea caledonica, from New Caledonia, Okadaia elegans from Japan and Pellibranchus cinnabareus from New Zealand, are all the same colour and the major features of their anatomy are identical. They all feed on spirorbid or similar tube worms, live in the intertidal zone and have direct development. The only feature distinguishing them has been the morphology of the radular teeth. In an animal so small, it is not surprising that different interpretations of the radular morphology have been reported from light microscope preparations. Risbec described a radula with two lateral teeth on each side and no rachidian, while both Ralph and Baba reported three lateral teeth on each side, the inner two teeth varying in denticulation in each species. More recently, Young has redescribed the teeth of specimens from Okinawa and reported for the first time a small rachidian tooth. I have prepared SEM mounts of specimens from New Caledonia which are identical to Young's description. I would consider all the earlier descriptions of the radular teeth to be attempts to describe the same morphology. Consequently Vayssierea caledonica is the earliest name for which we have anatomical information. However, as discussed above, Collingwood's description of Trevelyana felis from the South China Sea is clearly this species. Both Baba (1937) and Risbec (1953) refer to T. felis as a possible synonym or close relative. While species with direct development do not usually have widespread distributions, the relationship of this species to Spirorbis and other fouling tubeworms, suggests that this species has become widely distributed, either artificially, on the bottom of boats, or on floating laminarian algae, a common site for spirorbid settlement. As well as its wide distribution in the western Pacific, it is also reported from South Africa (Gosliner, 1987a) and Tanzania (personal observation).

Literature Cited:

        * Keramas = the Kerama Islands Group, located 30 ~ 40 kilometers west of the Okinawa capitol, Naha.


Page Date: 08 Nov '04
Page Modification Date: 08 Nov '04
Digitally manipulated photo
Copyright © 2004 Robert F. Bolland