 Aside from its vertebrae , Acrocanthosaurus had a typical allosauroid skeleton . Acrocanthosaurus was bipedal , with a long , heavy tail counterbalancing the head and body , maintaining its center of gravity over its hips . Its forelimbs were relatively shorter and more robust than those of Allosaurus but were otherwise similar : each hand bore three clawed digits . Unlike many smaller fast @-@ running dinosaurs , its femur was longer than its tibia and metatarsals , suggesting that Acrocanthosaurus was not a fast runner . Unsurprisingly , the hind leg bones of Acrocanthosaurus were proportionally more robust than its smaller relative Allosaurus . Its feet had four digits each , although as is typical for theropods , the first was much smaller than the rest and did not make contact with the ground . 
