Serendipity struck a group of Ohio State University geologists last December as they picked away at the stratified sediment in an ancient stream bed high in the frigid Transantarctic Mountains. Investigating rock strata to learn more about the Antarctic ice sheet, they uncovered a small fossilized bone fragment with continent-sized implications.
Asked by the Ohio State scientists to identify the 2½-in.-long fossil, Paleontologist Edwin Colbert, of the American Museum of Natural History, last week announced that it was a bit of jaw bone from a 3 to 4 ft. salamander-like creature that lived about 200 million years ago in the early Triassic period. It was the first evidence that land vertebrates had roamed Antarctica when its climate was warm.
What's more, the Antarctic animal belonged to a group of long-extinct freshwater amphibians called Labyrinthodonts, which are known to have lived in both Australia and South Africa in the early Triassic period. The discovery thus lent support to those who believe that Antarctica, Australia, South America and India were once a single supercontinent, called "Gondwanaland,"* that broke up and drifted apart. Creatures like the labyrinthodonts, the continental drifters argue, would not have evolved separately on such isolated continents as Antarctica and Australia.
Opponents of continental drift have argued that there is no good explanation for the stupendous forces that would be required to move continents thousands of miles apart and no reason for them to drift in different directions.
But after Paleontologist Colbert's identification, the burden is on them to explain how a fresh-water amphibian swam through hundreds of miles of saltwater ocean to reach Antarctica and die at the bottom of a stream only 325 miles from the South Pole.
*For the Gondwana region of India.