New Dinosaur Finds In Antarctica Paint Fuller Picture Of Past Ecosystem

The tooth of a duck-billed dinosaur, or hadrosaur, was found in sands about 66-67 million years old, from the Cretaceous period (about 1-2 million years before the asteroid impact that contributed to the extinction of the dinosaurs). The team that found the fossils is headed by Sergio Marenssi of the Instituto Antartico Argentino and Judd Case of St. Mary's College, California.

"This is the first duck-billed dinosaur to be found outside the Americas," said Mike Woodburne, University of California-Riverside paleontologist who is part of the project. "This gives us more support for the idea of a land bridge between South America and Antarctica at that time." The land bridge was used not only by dinosaurs but probably also by marsupial mammals dispersing from the Americas to Australia via Antarctica.

The hadrosaurs are a distinctive group of American dinosaurs, known for fancy crests on their skulls with networks of passageways that may have been used for vocalization and that may suggest the animals were social. Some stood perhaps 20 feet tall.

"This find allows us to paint a much fuller picture of what life was like in Antarctica at the time," commented Scott Borg, NSF program manager for Antarctic geology and geophysics. "The climate was obviously very different when these animals lived. There must have been a lot of vegetation to support these large plant-eaters. The find implies a complicated and robust ecosystem."

The region around Vega Island is extremely rich in both terrestrial and marine fossils, and the only such fossil trove in Antarctica to span the boundary of the Cretaceous and Tertiary periods, the time when the dinosaurs were wiped out.

The team also recovered a four-centimeter-long piece of a foot bone from what appears to be Antarctica's most ancient bird yet found. Also collected were numerous partial skeletons of gigantic marine reptiles called plesiosaurs and mosasaurs. According to James Martin, a South Dakota School of Mines paleontologist on the dig, these specimens included several juveniles which are very rare in the fossil record.

The group of paleontologists also includes members from the Smithsonian Institution and Argentina's Museo de la Plata.