WASHINGTON (Reuters) - Illuminating a mysterious epoch in the age of dinosaurs, scientists said on Monday they had unearthed two new species in New Mexico, including a bizarre one that sprang from the same lineage as super carnivore Tyrannosaurus rex but was content to eat plants.
The two dinosaurs -- the weird, sloth-like Nothronychus and a small carnivore from the coelurosaur family that has not yet been named -- lived 90 million years ago in a swampy forest similar to the bayous of Louisiana, said paleontologists Jim Kirkland and Doug Wolfe, who announced the discovery.
Both dinosaurs had bird-like characteristics and both probably were covered with feathers, the scientists said. They were found about a half mile apart near New Mexico's border with Arizona in an area dubbed the Zuni Basin, which had been just a few miles from the shores of a sea 1,000 miles wide that split North America.
At that time -- the middle of the Cretaceous period of the Mesozoic era -- Earth was in the throes of extreme global warming that melted the polar ice caps, raised ocean levels 1,000 feet higher than they are currently and reduced the amount of dry land on the planet.
Almost no dinosaur fossils have been found from that time, particularly in North America.
``This opens a window on a time period that otherwise we wouldn't know about,'' said Tom Holtz, a University of Maryland paleontologist who contributed to the research.
``TRULY, TRULY BIZARRE''
Nothronychus (pronounced ``no-thron-EYE-kus'') is a member of the theropod class of meat-eating dinosaurs that includes Tyrannosaurus and Allosaurus, but it apparently evolved into a plant-eater, said Kirkland, the state paleontologist for Utah.
It weighed about a ton, was 15 to 20 feet long and stood 10 to 12 feet tall, he said.
The creature was bipedal and walked more upright than its carnivore cousins, had a long, thin neck, long arms, dexterous hands, four-inch curved claws on its fingers, a large abdomen, a small head with a mouth full of leaf-shaped teeth designed for shredding vegetation, a relatively short tail and stout back legs, the scientists said.
``They are truly, truly bizarre,'' added Wolfe, director of the Zuni Basin Paleontological Project.
It is the first example of a group of dinosaurs called therizinosaurs to be found in the Americas. The others all came from China and Mongolia.
Nothronychus means ``sloth-like claw'' and Kirkland said it reminds him of giant ground sloths -- slow-moving Ice Age mammals with big claws that became extinct 10,000 years ago.
``Sort of a modern analog could be the panda,'' Holtz added, noting that the panda, one of the world's eight species of bears, also evolved from carnivores but eats only plants.
The scientists said no feathers were found with the fossil remains of Nothronychus, probably because the sediment in which it was discovered was not conducive to preserving such delicate features. Kirkland said the fossils of its Asian kin had preserved feathers and speculated that Nothronychus was covered in downy feathers, sort of like an emu. Wolfe said there is 40 to 50 percent of the skeleton of a single Nothronychus.
A LITTLE PREDATOR
The coelurosaur (pronounced ``suh-LOOR-oh-sawr'') was a bit more than seven feet long and three feet tall. Its body shape was similar to that of the much bigger Tyrannosaurus except it had longer arms. A relatively small predator, it ate smaller animals such as lizards and mammals.
Wolfe, who called the comparatively large-brained dinosaur ''the coyote of the Cretaceous,'' said there is 40 to 60 percent of a composite skeleton formed from two individuals.
No fossil evidence was found of feathers, but Wolfe noted that similar dinosaurs from Asia were found with feathers and speculated that this one had ``a loose gaggle of feathers around the head and along the spine, back of the arms and legs.''
The scientists made the announcement at a news conference sponsored by the U.S. cable TV network Discovery Channel, which funded the research and will air a special next month based on the findings.
Kirkland said scientists working at the site are now studying evidence of two other new dinosaur species, an armored herbivore and a ``duck-billed'' plant-eater, both measuring about 20 feet in length, as well as a small mammal.
The scientists also gave new details about a previously disclosed species, Zuniceratops, a two-horned precursor to the numerous horned dinosaurs such as Triceratops that flourished near the end of the age of dinosaurs 65 million years ago.
File Date: 6.23.01