Acrocanthosaurus

Acrocanthosaurus was a genus of theropod dinosaur that lived in North America during the Lower Cretaceous period. Its name means "high-spined lizard." This refers to the spines on its vertebrae, which formed a sail or hump when the animal was alive.

Acrocanthosaurus Temporal range: Lower Cretaceous 125 to 100 mya
Mounted Acrocanthosaurus skeleton at the North Carolina Museum of Natural Sciences.
Scientific classification
Kingdom:	Animalia
Class:	Sauropsida
Superorder:	Dinosauria
Order:	Saurischia
Suborder:	Theropoda
Infraorder:	Carnosauria
Family:	Carcharodontosauridae
Genus:	Acrocanthosaurus

Glen Rose theropod and sauropod tracks, with mounted Apatosaurus in the background, AMNH

Its classification is uncertain. It was originally classified as a spinosaur because the spines on its back looked like those of Spinosaurus. However, Acrocanthosaurus is now classified as a carnosaur. Most paleontologists believe that it was a carcharodontosaurid.

Acrocanthosaurus was 38 feet long, almost as large as Tyrannosaurus rex, and weighed about 6 or 7 short tons. It was the largest theropod in North America before the evolution of the tyrannosaurs.^[1]

Long, low ridges start at the nasal bones. They run along each side of the snout from the nostril back to the eye, and they continue onto the lacrimal bones.^[2] This is a characteristic feature of all allosaurids.^[3]

A famous trackway in Paluxy, Texas shows tracks of what might be an Acrocanthosaurus and its prey. While interesting and plausible, this hypothesis is difficult to prove, and other explanations exist.

In popular culture

Acrocanthosaurus was featured in an episode of the television documentary Monsters Resurrected. It was depicted as the top predator in early Cretaceous North America. A juvenile was scared away from its kill by a pack of Deinonychus, and was forced to hunt more difficult prey, such as a Sauropelta.