Re: Stiliger smaragdinus in Japan

August 6, 2001
From: Kathe R. Jensen

Dear Bill and Cynthia,

Sorry that I never got around to doing that generic description. This was something I discussed with Bob Burn, when I visited him more than 10 years ago. At that time I had only seen very small specimens, and didn't really believe him, when he claimed it differed so much from other species of Stiliger. However, when I found the mature specimens in Darwin Harbour, I had to agree about at least one character he had mentioned: they had like a "flange" on the stems of the larger cerata (like gills in some Doto species). So I contacted Bob Burn again, and we were supposed to write this "new genus" together - I think he has a "manuscript name" for it ready. However, then my contract at the Zoological Museum in Copenhagen expired, and I had to go to Finland. And since then I just haven't had time to look into this. After Cynthia sent me her note about the Japanese specimens, I looked in some of my old notes. It seems that most of the characters separating it from Stiliger (as well as from Hermaea and Caliphylla) are actually plesiomorphic, which would not qualify for a new genus. So, as you can see, I am still in doubt about its generic status. However, I can say that it is not an Aplysiopsis. It does not have the characteristic sabot-shaped teeth, nor the distal bifurcation on the rhinophores. The shape of the albumen gland is most similar to the hermaeid type, and if we accept this branching pattern as an apomorphic character, then it would be a "primitive" hermaeid - and therefore not a Stiliger (which is in the Limapontiidae).

Now I think I have made everybody confused - but I am also confused myself. This certainly shows that even a species which is easily identified can be very difficult to place in its "natural position" in the hierarchy of classification (and that one should never publish sentences like "a description of a new genus is in progress").
Cheers,
Kathe

jensen@ait.ac.th

Jensen, K., 2001 (Aug 6) Re: Stiliger smaragdinus in Japan. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/4908

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