(tie-RAN-oh-SORE-us) best known simply as T-rex, and first discovered by Barnum Brown in eastern Wyoming during 1900. Described by Henry Fairfied Osborn in 1905. T-rex has been debated to be both warm and cold blooded, preditor and scavenger. Tyrannosaurus made the news recently when viable protin was discovered in the fossilized bone of a new specimen. The concept of a slow moving, tail dragging beast has changed a lot over the 100 plus years since first dicoverd, and Tyrannosaurus is now thought to have been an agile hunter that may have lived in family groups. This tooth measures just over 5 inches when measuring along the curve.