STOP GLOBAL WARMING

Dinosaurs shared the Earth for millions of years
with the species that were their ancestors, a new study concludes. Dinosaurs
arose in the Late Triassic, between 235 million and 200 million years ago, and
came to dominate the planet in the Jurassic, 200 million to 120 million years
ago. Scientists had thought the dinosaurs rapidly replaced their ancestor
species. Indeed, until 2003, when a creature called Silesaurus was discovered
in Poland, no dinosaur precursors had been found from the Late Triassic. Now,
researchers report in the journal Science they have evidence from northern New
Mexico that dinosaurs and their precursor species coexisted for tens of
millions of years. Matthew T. Carrano, curator of dinosauria at the
Smithsonian’s National Museum of Natural History, said there has been a
long-standing debate over whether dinosaurs replaced earlier species gradually
or suddenly. "What they have is a snapshot of the transition, and it’s
clear there is a persistent environment with dinosaurs and these other older
animals. So, at least in this place in the southwestern U.S., it was not
abrupt," said Carrano, who was not part of the research team. "Finding
dinosaur precursors … together with dinosaurs tells us something about the
pace of changeover. If there was any competition between the precursors and
dinosaurs, then it was a very prolonged competition," Randall Irmis, a
graduate student at the University of California, Berkeley and co-author of the
report, said in a statement. The team reported finding 1,300 fossil specimens,
including several complete bones, at Hayden Quarry at Ghost Ranch, an area made
famous through the paintings of Georgia O’Keeffe. There were no complete
skeletons, and researchers are continuing to work at the site. Their finds included
bones from both early dinosaurs and dinosaur precursors as well as remains of
crocodile ancestors, fish and amphibians, all dating between 220 million and
210 million years ago. Included were leg bones of the carnivorous Chindesaurus
bryansmalli, a close relative of the Coelophysis, a well-known Triassic
dinosaur. They said both walked on two legs, reminiscent of the much later
Velociraptor depicted in the film "Jurassic Park." They also found
remains of a Dromomeron romeri, a relative of the 235 million-year-old
Argentinian middle Triassic precursor called Lagerpeton. Dromomeron was between
three and five feet long, the authors concluded. Another discovery was an
unnamed, four-footed beaked grazer about three times the size of  romomeron, they said. The research was funded
by the National Geographic Society, the Theodore Roosevelt Memorial Fund and
the Jurassic Foundation.