Re: Clione limacina in Greenland

November 12, 2007
From: Andy Murray

Concerning message #20716:

Thanks again for this great forum, and for your quick reply, Dr. Rudman. I finally got my hands on Pelagic Snails, and have just begun looking at it.

Based on the pictures and description in the book I think you are right about the mystery sacs being the feeding webs of the sea butterflies. I wonder about your theory of the kayaks scaring them into abandoning their webs, certainly I saw exponentially more of the sacs than the snails. I never saw one with it's web, which is why I didn't see any connection at the time. If I get back up there I'll have to observe more carefully. I wonder how much of an energy cost it is for the snail to abandon it's web?

I said before that I thought the sea butterflies were Limacina retroversa, but I only came to that conclusion through an email correspondence with another biologist. I could never actually find a picture until now. Upon seeing the pictures in the book I don't believe that was correct. L. helicina looks much closer, but still not quite right. The shell looks about right, in terms of size and shape, but the wings had serrated tips, giving a "feathery" appearance. I know there's no Peterson field guide to pelagic pteropods, but I wonder if you have any suggestions as to how I could get a better id?

One other question I have about the sea butterflies is; do you know if the mucous sac is the only way they feed? The first time I saw them, on the ice foot near Clyde River (Baffin Island) in Nov., they were periodically "landing" on the ice and crawling around on it like a benthic snail. I assumed at the time that they were grazing.

Thanks again, and take care,
Andy Murray

andyandmelanie@hotmail.com

Murray, A., 2007 (Nov 12) Re: Clione limacina in Greenland. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/21108

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