Russell (1970) synonymized

Gorgosaurus

libratus

with the genus Albertosaurus, and this was accepted by most subsequent workers (Paul 1988a; Molnar et al. 1990; Carpenter 1992). However, new studies of the material of Gorgosaurus indicate that it cannot be referred to Albertosaurus with any certainty (Holtz 1997, 2001 a; Currie, pers. comm. 1998); therefore, it is retained as a separate genus here.