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News on Utah fossils
UPI Science News
WASHINGTON, Oct. 13 (UPI) -- Scientists rummaging through a treasure
trove of rare fossils in Utah say they have gotten the first glimpse of
life during Earth's twilight zone -- the 80 million years separating the
massive vegetarian apatosaurus and the meat-eating T. rex.
Richard Cifelli, from the University of Oklahoma in Norman, says the
fossils come from a period of Earth's history known as the middle
Cretaceous, roughly 145 million to 65 million years ago.
He calls the period ``sort of a twilight zone,'' because most of its
fossil record has been erased by time and geological movements.
The 100-million-year-old fossils, from the Cedar Mountain Formation
in central Utah, paint a picture in which the last of a dying breed of
leaf-eating dinosaurs -- most no bigger than a St. Bernard -- and the
relatively puny ancestors of the monstrous T. rex -- only about 15 feet
(4.6 meters) long -- roamed the earth together.
Cifelli says that once the big vegetarians died out it appears ``it
took a few million years for dinosaurs to get big again.''
The researchers also found the world's oldest bones of marsupials,
the pouched mammals now found mostly in Australia. The fossils suggest
they got their start in North America and later migrated down through
South America and Antarctica.
Flowers also first bloomed in those years, replacing the taller,
greener vegetation that was cleared out by the giant leaf-eaters of the
late Jurassic period.
Researchers released the study today in the Proceedings of the
National Academy of Sciences.
(Written in New York by Mara Bovsun)
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