BUENOS AIRES - Argentine and U.S. scientists have found remains of a duck-billed dinosaur in Antarctica that could confirm theories of an ancient land bridge to the Americas used by migrating species, Argentine authorities said Wednesday. The team of scientists unearthed fossil remains of a
duck-billed dinosaur on Antarctica's Vega Island, as well as part of the foot of a prehistoric bird, the director of Argentina's National Antarctic Institute Brig. Gen. Jorge Edgard Leal said in a statement.
The duck-billed dinosaur remains, found in a layer of sand believed to be almost 70 million years old, were the first discovered outside the Americas, Leal said. "This implies the existence of a connection by land between South America and Antarctica in those times. This bridge was not just used by the dinosaurs but also by marsupials, which emigrated from the Americas to Australia via Antarctica," Leal said.
The team believes the 1.6 inch bird foot fragment may be the oldest remnant of a bird ever found in Antarctica. It was found in sediments 75 million years old. Among scientists on the dig are representatives from the National Antarctic Institute and the La Plata Museum in Argentina, as well as from the Smithsonian Institute and the South Dakota School of Mines.
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"We will only know what academic significance it may have after detailed research, "Jakubowski said. The lizard, the second known to have been discovered in amber on the Baltic coast in a century, was found near the city of Gdansk by a local jeweller who passed it on to the museum.
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Paul Olsen, a Columbia University paleontologist who made the discovery with the help of two amateurs from Reading, Pennsylvania, described the hypsognathus reptiles as foot-long, horned herbivores that resembled the modern-day groundhog in stature. They were among the crawling reptiles and salamander like amphibians that prevailed in the animal kingdom just before the age of dinosaurs at the dawn of the Mesozoic Era 248 million years ago.
Two of the white, partly preserved skulls showed up in a purplish mudstone deposit at a construction site in Exeter Township, Pennsylvania. The third was discovered in the town of Pennsburg. Both sites lie within 30 miles of Philadelphia, between Allentown and Pottstown.
A fourth skull, found among 150 ancient bones unearthed in Exeter, has yet to be identified. "We were looking at rocks at a construction site and there was so much new clean rock exposed after a rain, I thought there might be a lot more bones there than we had originally thought," Olsen said. "And lo and behold, once I really paid attention, there were." Olsen was scheduled to present his findings Saturday at a dinosaur symposium sponsored by Philadelphia's Academy of Natural Sciences.
The area where the hypsognathus skulls were discovered is part of the Newark rift basin, a geological formation created 190 million to 230 million years ago as North America pulled away from the ancient supercontinent known to scientists as Pangea. At about the same time, near the end of the Triassic Period and the beginning of the Jurassic Period, a mass extinction occurred among the older, established lines of animals, scientists like Olsen believe.
The course of evolution changed as a result, and dinosaurs were able to develop into giants such as the tyrannosaurus and brachiosaurus. Before the mass extinction, the biggest dinosaur had been no heavier than a cow. The cause of the extinction remains a mystery to science, largely because skeletal remains from the period have been very rare. The Exeter fossils have been dated to just 500,000 years before the extinction, which Olsen puts at about 202 million years ago.
The greatest thing about this find is that it is in well-dated rock near the Triassic-Jurassic boundary," observed Hans-Dieter Sues, curator of vertebrate paleontology at the Royal Ontario Museum in Toronto, where the Exeter skulls were being prepared. "Now we have evidence that these animals lived right up to the boundary, which supports our ideas about a large-scale extinction there," he said.
The eggs were dug up in a fossil field in Cal Ork'o, 440 miles southeast of the capital La Paz and near the city of Sucre. "Of the eggs we found, one measures 25 cm (10 inches) and the other, from a flying reptile, is big and measures 40 cm (16 inches)," Mayer said. The eggs were found after six weeks of digging and will be flown to Switzerland for laboratory analysis. "We have to prepare them and compare them with other remains and skeletons known throughout the world," Mayer said.
The fossil field, peppered with tracks from dozens of species, could be one of the largest in the world, Mayer said. Some of the tracks indicate beasts measuring up to 1,100 feet long, the longest yet known, he said. The tracks included footprints from Tyrannosaurus, the notorious meat eater. Bones at the site were from crocodiles, fresh water fish and turtles.
The expedition at Cal Ork'o is funded by the Swiss National Scientific Investigation Fund, the textile firm Mammut and local cement company FANCESA. Mayer said he had heard from Bolivian President Hugo Banzer that a foundation would be set up to preserve the site.