500 Mya Molting Arthropod

["Richard W. Travsky" <rtravsky@uwyo.edu>]

with picture


http://dsc.discovery.com/news/briefs/20040503/earlyinsect.html

May 6, 2004  For the first time ever, paleontologists have caught one of
the earliest animals in the act of doing something totally expected
shedding its skin.

The molting animal was captured in a 505-million-year-old fossil of a
bug-like arthropod sea creature call Marrella splendens, found in the
Burgess Shale of the Canadian Rockies. Although Marrella is the most
common animal fossil in the Burgess Shale, this is the only one, out of
many thousands, ever found actually in the process of casting off its old
skin. 
...
The reason it's so astounding is that molting just takes a few minutes and
it's unlikely an animal will be buried and killed  and then fossilized
during those few minutes.

"It's a very ephemeral event," confirmed paleontologist Desmond Collins of
the Royal Ontario Museum in Toronto.

Collins and Diego Garca-Bellido report on their unprecedented fossil find
in a short paper in this week's issue of Nature. 
...