Name: Acrocanthosaurus (High spined lizard). Phonetic: Ak-row-can-fo-sore-us. Named By: John Willis Stovall & Wann Langston, Jr. - 1950. Classification: Chordata, Reptilia, Dinosauria, Saurischia, Theropoda, Carcharodontosauridae. Species: A. atokensis (type). Type: Carnivore. Size: Up to 11.5 meters long. Known locations: USA, Oklahoma, Antlers Formation, and the Texas, Twin Mountains Formation. Some specimens from other parts of the US. Time period: Aptian to Albian of the Cretaceous. Fossil representation: Several specimens of partial remains. Combined study of all these specimens has allowed Acrocanthosaurus to be very well reconstructed.
Acrocanthosaurus immediately sticks out from other large theropods with its high dorsal spines than run from the neck to the tip of the tail. There have been many artistic representations for this structure from the spines standing proud from the body, to supporting a flap of skin. Modern thinking however comes from the examination of the lower spines that have attachments for muscles. This has led to the suggestion that the spines supported a hump of tissue that ran down the length of Acrocanthosaurus. The purpose of the hump of Acrocanthosaurus has been subject to a lot of speculation. Some have said that it would provide a larger surface area than Acrocanthosaurus would have had without it, helping with temperature exchange and reducing negative effects of gigantothermy. It could have been composed of fatty tissue and used to keepAcrocanthosaurus going for extended periods without eating. It may have also been a form of visual display for otherAcrocanthosaurs to gauge its level of health, perhaps even having a different colour or markings to the rest of its body. It is possible that the hump served double duty. If composed of fatty tissue, Acrocanthosaurus would have had to eat more than the minimum it would have had to just to survive. This would then result in a large and well maintained hump that would speak along the lines of 'Look at my hump. That is how much of a successful predator I am. That’s why I am more worthy of passing my genes down to the next generation'. It could have also worked in dominance displays between two Acrocanthosaurus, with the larger hump meaning that they were a more capable hunter and knew what to do when things came to a fight. The Acrocanthosaurus with the smaller hump would then probably back down instead of go up against what appeared to be a stronger and more capable Acrocanthosaurus.