Revised diagnosis. Tyrannosaurine diagnosed by the presence of a distinct mediolateral ridge along the dorsal margin of the epipterygoid fossa of the laterosphenoid and prominent interlocking bony papillae on the mandibular symphysis. In addition, the following features can be used to diagnose Daspletosaurus with the caveat that these cannot be currently assessed in Thanatotheristes: accessory cornual process of lacrimal; dorsal margin of maxillary process of lacrimal concealed in lateral view; cornual process of postorbital approaches laterotemporal fenestra; dorsal squamosal contact with postorbital terminates posterior to the anterior margin of the laterotemporal fenestra; anteroposterior ridge along nasal process of frontal; ventral keel on vomer; posterior pneumatic foramen of palatine positioned posterior to the anterior margin of the vomeroptergoid neck (see Carr et al., 2017).