Little asymmetric whatsits from Australia
may be the oldest fossils of full-fledged animal bodies yet discovered,
beating the previous contenders by tens of millions of years and pushing
the evidence for animal life into an earlier geologic time.
The newly unveiled fossils, which resemble sponges, come from rocks
between 635 million and 659 million years old, Adam Maloof of Princeton
University and his colleagues report online in Nature Geoscience August
17. That timing sandwiches the fossils between two cold spells that iced
over most of the planet during a Hollywood-disaster-style geologic
period called the Cryogenian.
The proposed animal fossils do "have all the hallmarks" of being
something
more than just fragments of microbial mats, says biogeochemist Roger
Summons of MIT, who was not involved in the study. These layers of
single-celled
organisms dominated the fossil record for billions of years before the
appearance of true multicelled animals.
------------------------------------
Yahoo! Groups Links
<*> To visit your group on the web, go to:
http://groups.yahoo.com/group/geology2/
<*> Your email settings:
Individual Email | Traditional
<*> To change settings online go to:
http://groups.yahoo.com/group/geology2/join
(Yahoo! ID required)
<*> To change settings via email:
geology2-digest@yahoogroups.com
geology2-fullfeatured@yahoogroups.com
<*> To unsubscribe from this group, send an email to:
geology2-unsubscribe@yahoogroups.com
<*> Your use of Yahoo! Groups is subject to:
http://docs.yahoo.com/info/terms/
No comments:
Post a Comment