Fig. 5 in 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

Fig. 5 Stratigraphic-temporal separation of adults of western North American Campanian– Maastrichtian tyrannosaurid species, to same scale, bar equals 2 m, showing sudden size increase in Late Maastrichtian in association with retreating interior seaway resulting in reconnection of North America into a contiguous continent. From bottom to top; Gorgosaurus libratus (2.6 tonnes), Albertosaurus sarcophagus (2.8), Tyrannosaurus imperator (7.2), T. regina (7.4). Stippled areas are the formations that preserve the illustrated tyrannosaurids, from bottom to top Dinosaur Park, Horseshoe Canyon, TT-zone