Ecologically distinct dinosaurian sister group shows early diversification of Ornithodira. 2010. S. Nesbitt, et al. Nature 464: 95-98.
At least 14 individuals of the new species Asilisaurus kongwe (a-SEE-lee-SOAR-us KONG-way) were recovered from a single bone bed in southern Tanzania. The individuals stood about 0.5 to 1 m tall at the hips and were 1 to 3 m long. They weighed about 10 to 30 kg. Asilisaurus walked on four legs and most likely ate plants or a combination of plants and meat. They lived about 240 million years ago.
Asilisaurus is part of a sister group to dinosaurs known as silesaurs. Silesaurs are considered dinosaur-like because they share many dinosaur characteristics but still lack key characteristics all dinosaurs share. Even though the oldest dinosaurs discovered so far are only 230 million years old, the presence of their closest relatives 10 million years earlier implies that silesaurs and the dinosaur lineage had already diverged from common ancestors by 240 million years ago. Silesaurs continued to live side by side with early dinosaurs throughout much of the Triassic Period (between about 250 and 200 million years ago).