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New UMD study suggests that everywhere tyrannosaurs rose to dominance, their juveniles took over the ecological role of medium-sized carnivores A new study shows that medium-sized predators all but disappeared late in dinosaur history wherever Tyrannosaurus rex and its close relatives rose to dominance. In those areas—lands that eventually became central Asia and Western North America—juvenile tyrannosaurs stepped in to fill the missing ecological niche previously held by other carnivores. The research conducted by Thomas Holtz, a principal lecturer in the University of Maryland's Department of Geology, verified previous anecdotal reports of a dramatic drop-off in diversity of medium-sized predator...

The first known fossilized skin impressions for Tyrannosaurus rex suggest that this gigantic carnivore, unlike many other dinosaurs, had little to no feathers. The fossils, reported in the journal Biology Letters, show that T. rex was instead covered with a tough and scaly hide. Fossilized skin impressions for other tyrannosaurs — including Albertosaurus, Gorgosaurus, and Daspletosaurus — reveal that all such dinosaurs lacked feathers, too.

New Haven, Conn.—It turns out that the undisputed king of the dinosaurs, Tyrannosaurus rex, didn't just eat other dinosaurs but also each other. Paleontologists from the United States and Canada have found bite marks on the giants' bones that were made by other T. rex, according to a new study published online Oct. 15 in the journal PLoS ONE. While searching through dinosaur fossil collections for another study on dinosaur bones with mammal tooth marks, Yale researcher Nick Longrich discovered a bone with especially large gouges in them. Given the age and location of the fossil, the marks had to...

NEW YORK - Scientists say they've found the earliest known tyrannosaur, shedding light on the lineage that produced the fearsome Tyrannosaurus rex. The discovery comes with a puzzle: Why did this beast have a strange crest on its head? Digging in the badlands of northwestern China that appeared in the movie "Crouching Tiger, Hidden Dragon," researchers found two skeletons of a creature that lived some 160 million years ago. That's more than 90 million years before T. rex came along. A two-legged meat-eater, the beast was far smaller than T. rex, measuring about 10 feet from its snout to the...