Oxynoe kabirensis
Hamatani, 1980

Order: SACOGLOSSA
Superfamily: OXYNOOIDEA
Family: Oxynoidae

DISTRIBUTION

Known only from Japan

PHOTO

Hachijo Island, Japan. 30mm long, depth: 10m. Photo: Shouichi Kato

Hamatani notes some differences in the shape of the shell, and considers the radular teeth of O. kabirensis to be somewhat wider than the teeth of O. viridis, but the main difference is in the shape and colour of the living animal. The background colour of O. kabirensis varies from a pale yellowish green to a dark green, but whatever the color there is always a darker region at the base of the parapodia which extends up as a triangular peak in the middle of the parapodia. There can also be secondary peaks at the front and back of the parapodia. The edge of this darker patch is lined with an even darker line. There can be some yellowish spots on the parapodia and there are usually a few scattered very elongate retractile papillae. In O. viridis the background colour is uniform, there being no darker green patch on the parapodia, and usually there are scattered blue spots.

Reference:
• Hamatani, I. (1980) On the species of the genus Oxynoe Rafinesque, 1819 from Japan, inclusive of a new species (Opisthobranchia: Ascoglossa). Publications of the Seto Marine Biological Laboratory, 25(5-6): 349-360.

Authorship details
Rudman, W.B., 2002 (April 28) Oxynoe kabirensis Hamatani, 1980. [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/oxynkabi

Related messages


Oxynoe kabirensis at Hachijo Island

May 11, 2002
From: Nishina Masayoshi


Dear Bill,
Here are some photos of the head of Oxynoe kabiraensis.

Photo by N.Masayoshi at Hachijo Island.

Best Regards,
Nishina Masayoshi

nishina@wips.co.jp

Masayoshi, N., 2002 (May 11) Oxynoe kabirensis at Hachijo Island. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/6829

Thanks Nishina,
Bill Rudman


Colour camouflage in Oxynoe kabirensis

May 11, 2002
From: Nishina Masayoshi


Dear Bill,
To accompany my other images of Oxynoe kabiraensis here is one showing how I think it is camouflaged when living on the Caulerpa on which it feeds. From the dorsal view, you can see that the dark triangle pattern breaks the light green part of the body into two rounded regions wjhich look similar in shape and size to the Caulerpa's 'ramuli'

Photo by N.Masayoshi at Hachijo Island.

Best Regards,
Nishina Masayoshi

nishina@wips.co.jp

Masayoshi, N., 2002 (May 11) Colour camouflage in Oxynoe kabirensis. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/6915

Dear Nishina,
Thanks for this fascinating photo. I have included a close-up of the animal so it is easier to find in the whole photo at the top. It certainly looks as though the animal's colour pattern is to help it hide, much like the southeastern Australian bivalved sacoglossans such as Midorigai australis.
Best wishes,
Bill Rudman

Rudman, W.B., 2002 (May 11). Comment on Colour camouflage in Oxynoe kabirensis by Nishina Masayoshi. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/6915

Oxynoe kabirensis from Hachijo Island, Japan

April 29, 2002
From: Shouichi Kato

Dear Bill,
Please see attached 4 pictures. There are 3 animals from Hachijo Island, Japan, that I think are all variations of Oxynoe kabirensis. But as we can find so many variations, there is an opinion these are the variations of Oxynoe viridis.
I would like to know how we can identify these two species and if these three are all the same species. I always very much appreciate your advice.

Picture (a) (a and b found together)
size; 30mm depth; 3m
Picture (b)
size; 25mm depth; 3m
Picture (c) and (d) (same animal)
size; 30mm depth; 10m

Thanks and best regards,
S. Kato

regulus@edit.ne.jp

Kato, S., 2002 (Apr 29) Oxynoe kabirensis from Hachijo Island, Japan. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/6700

Dear Shouichi,
These all certainly fit Hamatani's description of Oxynoe kabirensis which fortunately included a description and illustrations of the living animal, and a comparison with Oxyemnoe viridis.

Hamatani notes some differences in the shape of the shell, and considers the radular teeth of O. kabirensis to be somewhat wider than the teeh of O. viridis, but the main difference is in the shape and colour of the living animal. The background colour of O. kabirensis varies from a pale yellowish green to a dark green, but whatever the color there is always a darker region at the base of the parapodia which extends up as a triangular peak in the middle of the parapodia. There can also be secondary peaks at the front and back of the parapodia. The edge of this darker patch is lined with an even darker line. There can be some yellowish spots on the parapodia and there are usually a few scattered very elongate papillae, which are probbaly retractile. In O. viridis the background colour is uniform, there being no darker green patch on the parapodia, and usually ther are scattered blue spots.

• Hamatani, I. (1980) On the species of the genus Oxynoe Rafinesque, 1819 from Japan, inclusive of a new species (Opisthobranchia: Ascoglossa). Publications of the Seto Marine Biological Laboratory, 25(5-6): 349-360.

Thanks very much for these photos, they are an interesting addition to Hamatani's original description.
Best wishes,
Bill Rudman

Rudman, W.B., 2002 (Apr 29). Comment on Oxynoe kabirensis from Hachijo Island, Japan by Shouichi Kato. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/6700