Leech cocoon preserves 200-million-year-old fossil

Move over amber. When it comes to preserving soft-bodied animals through the ages, there's a newcomer in town: fossilised leech "cocoons".

The cocoons are secreted by many leech and worm species as mucous egg cases that harden and often fossilise. Almost two decades ago, Norwegian scientists found a perfectly preserved nematode worm embedded in the wall of a fossilised cocoon, but no one had investigated further.

So when Benjamin Bomfleur, a palaeobiologist at the University of Kansas, and his colleagues found fossil cocoons in 200-million-year-old rocks from the mountains of Antarctica, they took a closer look. They dissolved the rock with acid, leaving only the organic material - mostly leaf litter, but also 20 leech cocoons squashed flat by the pressure of aeons. One contained a perfectly preserved ciliated protozoan that appeared identical to modern single-celled "bell animals" (Vorticella) that live in ponds and streams.

The find is one of only a handful of fossilised ciliated protozoans. It suggests leech cocoons could be conservation traps in which, like amber, rarely fossilised creatures might be found.

Journal reference: PNAS, DOI: 10.1073/pnas.1218879109

If you would like to reuse any content from New Scientist, either in print or online, please contact the syndication department first for permission. New Scientist does not own rights to photos, but there are a variety of licensing options available for use of articles and graphics we own the copyright to.

Have your say

Only subscribers may leave comments on this article. Please log in.

Only personal subscribers may leave comments on this article

Subscribe now to comment.

All comments should respect the New Scientist House Rules. If you think a particular comment breaks these rules then please use the "Report" link in that comment to report it to us.

If you are having a technical problem posting a comment, please contact technical support.

Source: http://feeds.newscientist.com/c/749/f/10897/s/263a0cf1/l/0L0Snewscientist0N0Carticle0Cdn225690Eleech0Ecocoon0Epreserves0E20A0Amillionyearold0Efossil0Bhtml0Dcmpid0FRSS0QNSNS0Q20A120EGLOBAL0Qonline0Enews/story01.htm

leah messer freedom riders 9th circuit court of appeals gisele bundchen tom brady randy travis arrested dickens greg kelly