Tarbosaurus (Maleev, 1974)

Holtz, TR jr., 2004, Tyrannosauroidea, The Dinosauria, University of California Press, pp. 111-136 : 1

Tarbosaurus and Tyrannosaurus

share the following features: the ventral curvature of the maxilla pronounced, the ventral deflection of the curvature being at least as long as the crown of the largest premaxillary teeth; the lateral lamina of the maxilla obscuring the large shelf overlapping the rostral part of the maxillary antrum in lateral view; the lateral projections of the caudal suture of the nasal extending farther caudally than the medial projections; the dorsal ramus of the lacrimal having an inflated appearance; the lacrimal recess having multiple openings; the main body of the frontal rectangular, only a small triangular rostral prong remaining; the supratemporal fossa occupying most of the caudal portion of the frontal, the latter meeting along the midline to form a frontal sagittal crest; the postorbital dorsal surface forming a large rugose boss in adults; the postorbital suborbital prong present and prominent in adults; the palatines trapezoidal; two foramina on the lateral surface of the palatines (also in the Canadian albertosaurines); the transverse nuchal crest rostrocaudally thick with a rugose dorsal margin; the basal tubera reduced, being smaller than the ventral ends of the basipterygoid processes; the occipital region directed caudoventrally; the dorsoventral depth of the caudal end of the dentary greater than 200% of the depth of the dentary symphysis; the ratio of metacarpal II to metacarpal I 170% or less; and the manual ungual having blunted distal tips and reduced curvature. Some authors (Paul 1988a; Carpenter 1992b; Holtz 1994, 1995b, 2001b; Carr 1999; Carr and Williamson, in press) have placed both the giant Asian form and the giant North American form in the single genus Tyrannosaurus .