Re: Stiliger akkeshiensis from Kuril Islands

September 9, 2005
From: Bill Rudman

Note added 2 March 2006: Russian animals are now considered to be Hermaea vancouverensis [see message #15995].

Concerning message #14612:

I have prepared a Fact Sheet for Stiliger akkeshiensis, based on Alexei's photos. This species was described from Akkeshi Bay, Hokkaido, on the basis of a 6 preserved specimens, about 4mm long preserved. All we know about its colour is the sentence "preserved specimens have traces of blackish mottles and streaks on the head, rhinophores, back, tail and sides.." The illustration of the radula in Baba's description is very similar to the one illustrated here.

If Alexei Chernyshev's description is correct then we can add considerably to the original description. The body has a translucent yellowish tinge and there is a large purplish patch on each side of the head in front of the rhinophores. There is a purplish line running from the patch back to the rhinophores and a ring of the same colour around the rhinophore stalk. A dark line runs back from each rhinophores, on the inside of the eye, to meet its counterpart from the other side in the dorsal midline just in front of the first cerata. It is possible that these lines are a branch of the digestive gland duct, because a very similar looking dark line runs back on eacg side linking the bases of all the cerata. There are a few blackish purple marks on the dorsum, between the single row of cerata, and in one animal there is a distinct median line behind the most posterior cerata. Dark purplish lobules of the digestive gland can be seen through the transparent ceratal wall.

Baba considered this species to belong the subgenus Ercolania.

• Baba, K. (1935) The fauna of Akkeshi Bay. 1. Opisthobranchia. Journal Faculty Science, Hokkaido Imperial University, series 6, Zoology 4: 115-125. (Pls.7-8)
• Baba, K. (1959) The family Stiligeridae from Japan (Opisthobranchia- Sacoglossa). Publications of the Seto Marine Biological Laboratory, 7: 327-334.

Rudman, W.B., 2005 (Sep 9) Re: Stiliger akkeshiensis from Kuril Islands. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/16005

Copyright © Australian Museum, 1998-2010