 The holotype of Gorgosaurus libratus ( NMC 2120 ) is a nearly complete skeleton associated with a skull , discovered in 1913 by Charles M. Sternberg . This specimen was the first tyrannosaurid found with a complete hand . It was found in the Dinosaur Park Formation of Alberta and is housed in the Canadian Museum of Nature in Ottawa . Prospectors from the American Museum of Natural History in New York City were active along the Red Deer River in Alberta at the same time , collecting hundreds of spectacular dinosaur specimens , including four complete G. libratus skulls , three of which were associated with skeletons . Matthew and Brown described four of these specimens in 1923 . 
