WASHINGTON -- Frozen Antarctica has yielded two of its secrets, previously unknown types of dinosaurs that lived there millions of years ago when the climate was milder.
The discoveries, made thousands of miles apart, were announced Thursday by the National Science Foundation.
One of the finds is a relative of the fierce tyrannosaurs that would have lived many millions of years after the other, a plant-eating beast, was alive.
The carnivore was found on James Ross Island, off the coast of the Antarctic Peninsula, by Judd Case, James Martin and their research team.
According to their report, the bones represent a new species of carnivorous dinosaur related to the enormous meat-eating tyrannosaurs and the voracious, but smaller and swifter, velociraptors featured in the movie "Jurassic Park."
The researchers said features of the animal bones and teeth suggest the creature may represent a population of carnivores that survived in the Antarctic long after they had been succeeded by other predators elsewhere on the globe.
"One of the surprising things is that animals with these more primitive characteristics generally haven't survived as long elsewhere as they have in Antarctica," said Case, dean of science and a professor of biology at Saint Mary's College of California. "But, for whatever reason, they were still hanging out on the Antarctic continent."
Martin, curator of vertebrate paleontology at the South Dakota School of Mines & Technology, said the size and shape of the ends of the lower-leg and foot bones indicate that the animal was a running dinosaur roughly 6 to 8 feet tall.
Relatively few dinosaur fossils from the end of the Cretaceous Period, which lasted from 144 million to 65 million years ago, have been found in Antarctica.
This was one of only six dinosaur fossils that have been discovered in the James Ross region of the Antarctic Peninsula, the land mass that juts north from the southernmost continent toward South America.
Thousands of miles away in the continent's interior, a team led by William Hammer of Augustana College in Rock Island, Ill., found embedded in solid rock what they believe to be the pelvis of a primitive sauropod, a four-legged, plant-eating dinosaur similar to better-known creatures such as the brachiosaurus and diplodocus - dinosaurs with long necks and tails and small heads.
The area known as Mount Kirkpatrick, was once a soft riverbed before millions of years of tectonic activity elevated it skyward.
Hammer, who discovered another dinosaur in that area in 1991, had returned to the site of that find to continue his work.
Based on field analysis of the bones, Hammer and his fellow researchers believe the pelvis, roughly 3 feet across, is from a primitive sauropod that represents one of the earliest forms of the emerging dinosaur lineage that eventually produced animals more than 100 feet long.
Basing his estimates on the bones excavated at the site, Hammer suggests the new, and as-yet-unnamed creature was between 6 and 7 feet tall and up to 30 feet long.
Hammer said that the rocks in which the find was made helped scientists determine that the creature lived roughly 200 million years ago, millions of years before the creature Case and Martin discovered on the Antarctic Peninsula.