The oldest dinosaur?

Paleontologists don't always have to go into the field to make new discoveries. Bones found in the collections of The Natural History Museum in London, collected some 80 years ago in southern Tanzania, may belong to one of the earliest known dinosaurs. This news was reported online in Biology Letters1 by UCMP alum Sterling Nesbitt and current UCMP grad student Sarah Werning in December.

Until this latest discovery, the oldest well-dated and unambiguous dinosaurs were known from the Late Triassic of Argentina, but the new specimen — Nyasasaurus parringtoni — pushes dinosaur origins back another 10-15 million years to the Middle Triassic. The find lends support to phylogenetic analyses that had predicted Dinosauria had Middle Triassic roots.

Although the Nyasasaurus material consisted of just a humerus and six vertebrae, a morphological study revealed several shared dinosaurian characters and Sarah's histological analysis of the bones showed that, like dinosaurs, Nyasasaurus bone grew at a rapid, sustained rate.

1Nesbitt, S.J., P.M. Barrett, S. Werning, C.A. Sidor, and A.J. Charig. 2012. The oldest dinosaur? A Middle Triassic dinosauriform from Tanzania. Biology Letters 9(1). doi: 10.1098/rsbl.2012.0949