Theropods are clawed bipedal dinosaurs. Many were carnivorous and well-equipped with sharp, serrated teeth. This group is not extinct, for it includes birds! Accordingly, they range in size from a 2-inch hummingbird to 43-foot-long giants such as Carcharodontosaurus and Giganotosaurus.
The largest theropod in the Early Cretaceous of North America was Acrocanthosaurus atokensis. Fossilized bones and teeth of this predator have been found in Texas and Oklahoma. Adult Acrocanthosaurus reached a length of 40 feet and weighed an estimated 6.8 tons. This allosauroid theropod is related to Allosaurus and Carcharodontosaurus, and is named for the elongated spines on its vertebrae.
Given the size of this dinosaur and the size of the theropod tracks found in the Paluxy River near Glen Rose, Acrocanthosaurus is thought to be the track maker – at least until a new large Early Cretaceous theropod is discovered in the region!