March 16, 2010

How old are dinosaurs? Older than we thought!

Here’s some breaking news: dinosaurs may have lived much earlier than previously thought!

Burke Museum curator of vertebrate paleontology Christian Sidor and a team of paleontologists recently discovered that a dinosaur-like creature called Asilisaurus kongwe lived as many as 10 million years earlier than the oldest known dinosaurs.

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. The relationship between silesaurs and dinosaurs is analogous to the close relationship of humans and chimpanzees. Sidor and his colleagues concluded that dinosaurs might also have lived at the time of Asilisaurus – bumping back the age of the oldest dinosaurs by 10 million years.

The Asilisaurus fossil bones were recovered from a single bone bed in southern Tanzania, making it possible to reconstruct a nearly entire skeleton. The creature would have stood about 1.5 to 3 feet tall and 3 to 10 feet long, weighing between 22 to 66 pounds. The description of the new species appeared in a paper published March 4 in Nature. The lead author is Sterling Nesbitt, at The University of Texas. Sidor is among the co-authors.

An article in the University Week gives more detail about the new species. Christian Sidor was also recently featured on NPR’s Science Friday, in an interview about the discovery. Click here to listen to his interview.

Posted by: MaryAnn Barron Wagner, Communications

Photos: (center) A life recreation of Asilisaurus kongwe. Marlene Hill Donnelly, Field Museum; (right) Christian Sidor excavates a fossil from the Manda beds in Tanzana in 2007, photo by L. Tsuji.