ROANOKE TIMES
Copyright (c) 1996, Roanoke Times
DATE: Sunday, May 26, 1996 TAG: 9605290062
SECTION: NATIONAL/INTERNATIONAL PAGE: A-7 EDITION: METRO
DATELINE: WASHINGTON
SOURCE: PAUL RECER ASSOCIATED PRESS
TOOTH FOSSILS SUGGEST plant-eating mammals from 65 million years ago led to animals as varied as antelopes, whales and elephants.
Ancestors of hoofed animals may have evolved during the time of the dinosaurs - about 20 million years earlier than previously believed.
An evaluation of tooth fossils found in 85-million-year-old sediment in Asia suggests they bear the marks of animals that grazed and could be from the ancestors of modern day horses, cows, elephants and other hoofed animals.
The study, by J. David Archibald of San Diego State University, was published Friday in the journal Science.
Experts said the finding suggests that the ancestors of hoofed, grazing animals, called ungulates, were present at the same time that dinosaurs were the dominate life form on Earth.
Dinosaurs disappeared about 65 million years ago. The most popular theory has been that mammals were few in number and variety about then, but that the species quickly evolved over the following millions of years to fill ecological niches left vacant by the demise of the dinosaurs.
But Archibald's findings suggest that the evolution of ungulates actually was well under way before the dinosaurs were gone.
Archibald said tooth fossils recovered from the Bissekty Formation in Uzbekistan resemble teeth found in animals that lived millions of years later. The fossil teeth are the size of rat teeth.
The teeth had the flat, squared grinding surfaces similar to what is found in herbivores' teeth.
Archibald said fossils from 65 million years ago show that the diversity of ungulates then alive led to eventual development of animals as varied as antelopes, whales and elephants. The teeth, he said, provide ``evidence for rooting the ungulate radiation much farther back in time.''
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