Comparison of dog-sized Zhenyuanlong with giant Tyrannosaurus showing reduction of the limbs, reduction of the integument (feathers), deeper mandible and much greater size. This was created several years ago before the addition of Daspletosaurus, Gorgosaurus, Tarbosaurus and other pertinent taxa, yet remains accurate.

Daspletosaurus torosus (Russell 1970; Late Cretaceous, 79mya; 9m in length) nests in the LRT and elsewhere between Gorgosaurus and Tarbosaurus (below) sharing traits found in one, the other or both. Differences are more notable in dorsal view. Note the broader muzzle, but the cheeks are not so broad yet. The premaxilla is ventrally transverse and lateral ascending processes are not visible in lateral view.

Tarbosaurus bataar (Maleev 1955; Hurum and Sabath 2003; Late Cretaceous) nests basal to the Tyrannosaurus clade in the LRT, derived from Gorgosaurus. The differences are subtle. Note the difference in rostral width in two specimens of Tarbosaurus.

Tyrannosaurus rex (Osborn 1905) Late Cretaceous, 65 mya, 12.3 m in length, was derived from a larger and more robust descendant of Gorgosaurus and Zhenyuanlong. The rostrum and cheeks were broader. Several specimens are known.

Eotyrannus lengi (Hutt et al. 2001, Naish 2006; Early Cretaceous) is a mid-sized theropod originally and later allied with tyrannosauroids like Tyrannosaurus. The resemblance to Late Cretaceous taxa, both in size and shape, is striking, but too little is known of this specimen to make it a taxon in the LRT.

Holtz TR. Jr 1994. The phylogenetic position of the Tyrannosauridae: implications for theropod systematics. Journal of Paleontology. 68 (5): 1100–1117.

Hurum JH and Sabath K 2003. Giant theropod dinosaurs from Asia and North America: Skulls of Tarbosaurus bataar and Tyrannosaurus rex compared. Acta Palaeontologica Polonica 48 (2): 161–190. http://app.pan.pl/acta48/app48−161

Hutt S et al. (4 coauthors) 2001. A preliminary account of a new tyrannosauroid theropod from the Wessex Formation (Cretaceous) of southern England. Cretaceous Research. 22: 227–242.

Maleev EA 1955. Gigantic carnivorous dinosaurs from Mongolia [in Russian]. Doklady AN SSSR 104 (4): 634–637.

Osborn HF 1905. Tyrannosaurus and other Cretaceous carnivorous dinosaurs. Bulletin of the AMNH (New York City: American Museum of Natural History) 21 (14): 259–265.

Paul GS, Persons WS4 and Van Raalte J 2022. The Tyrant Lizard King, Queen and Emperor: Multiple Lines of Morphological and Stratigraphic Evidence Support Subtle
Evolution and Probable Speciation Within the North American Genus Tyrannosaurus. Evolutionary Biology https://doi.org/10.1007/s11692-022-09561-5

Russell DA 1970. Tyrannosaurs from the Late Cretaceous of Western Canada. National Museum of Natural Sciences Publications in Palaeontology 1:1–34.

wiki/Daspletosaurus
wiki/Tyrannosaurus
wiki/Eotyrannus
wiki/Tarbosaurus