The distribution of dinosaurs was limited by climate and by their inability to exist in deserts. Dry areas were a barrier to migration, and Virginia was in the middle of Pangea far from the moist coast. However, the first dinosaurs were limited to humid areas. The supercontinent of Pangea allowed species on land to migrate without crossing any part of the Panthalassa Ocean. 2ĭinosaurs first appeared in what is now South America, but at the start of the Triassic Period there were no separate continents. Today's birds are the survivors of the avemetatarsalian line, which also produced the dinosaurs of the Mesozoic Era. Today's alligators and crocodiles are descendants of the pseudosuchian line of archosaurs. Species with a hip/leg arrangement for walking upright, such as the archosaurs that appeared after the Permian extinction, could move faster on land. Their lungs were especially efficient at extracting oxygen and removing heat, like the lungs of modern birds today. Dinosaurs grew fast, an essential characteristic since no Tyrannosaurus rex survived more than 30 years. 1Īs life refilled the niches, they had the advantage of walking upright, unlike the sprawling gait of salamanders and lizards. At the time, Virginia was in the center of Pangea and the solar system was on the other side of the Milky Way galaxy, making its 250-million year rotation around the black hole in the center. Various types of dinosaurs have lived in Virginia since that form of life evolved 230-240 million years ago, during the Triassic Period. Source: US Geological Survey, Culpeper East 7.5x7.5 topographic quadrangle (2013) In 1989, dinosaur tracks were revealed at the Culpeper Stone Company near Stevensville
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