Opisthobranch of the Week Data
Thuridilla kathae is currently unknown from Okinawa's main Island as of early-March, 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 January of 1999, on a buoy chain in 7m of water. Atsushi's photograph is used here with his kind permission and he considers the species to be common; Atsushi reports (per. comm.) seeing more than thirty individuals in a single year in the Keramas, and several have been collected.
The following, in part, is taken from Gosliner (1995):
The living animals are a rich green with a scattering of large and small opaque white spots. The large spots form low papillae. The margin of the parapodia is cream to light yellow. There is a y-shaped opaque white mark on head that extends on to the base of the rhinophores. This white is followed by an area of green and then a second patch of opaque white. The tips of the rhinophores are ornamented with orange. Orange pigment is also present on the anterior margin of the foot.
Gosliner (1995) named the animal for Kathe Jensen, a prominent researcher of sacoglossans.
I've added a second image of T. kathae, a 3.5mm juvenile showing the prominent y-shaped opaque white mark on head, described above by Gosliner.
Thuridilla undula is one of eleven described species of Thuridilla found in Okinawan waters. The eleven species are:
T. albopustulosa T. bayeri T. carlsoni T. flavomaculata T. gracilis To be featured at an later date T. hoffae T. kathae (the above featured animal) T. livida T. splendens T. undula T. vatae