Tarbosaurus
"Both Asiatic and North American... tyrannosaurines [NAT] hunted large prey, whilst also being opportunistic scavengers. However, the prey available to them were obviously different... the adult T. rex... probably specialized in bringing down large horned dinosaurs, like Triceratops... but this group was absent outside North America. Thus, the Mongolian tyrannosaurines were forced to feed on sauropods... These differences in typical prey items might have exerted different selective pressures, concerning hunting strategy and mechanical requirements maximizing their success rate as predators".