Acrocanthosaurus (High spined lizard)
John Willis Stovall & Wann Langston, Jr. - 1950
Up to 11.5 meters long
A. atokensis (type)
USA, Oklahoma, Antlers Formation, and the Texas, Twin Mountains Formation. Some specimens from other parts of the US
Early Cretaceous, 115-105 million years ago
Acrocanthosaurus (/,aekroU,kaenth@'so:r@s/ ak-ro-KAN-th@-SAWR-@s; meaning “high-spined lizard”) is a genus of carcharodontosaurid dinosaur that existed in what is now North America during the Aptian and early Albian stages of the Early Cretaceous. It is named for its large neural spines taken from the Greek Akra/Akra (‘high'), akantha/akantha (‘thorn or'spine') and saUros/sauros (‘lizard').
The fossil remains are discovered mostly throughout three U.S. states of Oklahoma, Texas, and Wyoming, and teeth believed to belong to the animal have been discovered in the east of Maryland. It was an animal that was a bipedal predator and was likely to be an apex predator that was a prey for sauropods, ornithopods, as well as ankylosaurs. Recent discoveries have clarified numerous details about its anatomy and allowed for the development of specialized research focused on its brain structure and the function of its forelimbs.
The holotype and paratype (OMNH 10146 and OMNH 10147) were discovered in the early 1940s and published in 1950. Two more complete specimens (SMU 74646 and NCSM 14345) were recovered in the late 1990s and are now in the Fort Worth Museum of Science and History collection. The existence of Acrocanthosaurus in the Cloverly Formation was established in 2012 by the description of another partial skeleton UM 0797. This specimen, comprised of pieces of two vertebrae pubic bones that are partially buried as well as a femur, partial fibula, as well as fragments, indicates an animal that was a young one. It was found in a bone bed located in the Bighorn Basin of north-central Wyoming close to the shoulders of the Sauroposeidon.
Acrocanthosaurus was one of the largest theropods to exist, with the largest fossil (NCSM 4345) measuring 11.5 millimeters (38 feet) from the snout to the tip of its tail and a maximal weight of 7.25 tonnes (7.99 shorter tonnes). Its skull was large and narrow, as with other allosauroids, and could represent one of the eastern representatives in the Genus. The opening that reduced weight in the front of the socket for the eye was quite big and the exterior of the maxilla and upper portion of the bone on the top of the snout were rougher than those found in Giganotosaurus and Carcharodontosaurus. The ridges were long and low and arose from the nasal bones. There was no obvious lacrimal bone with a crest just in front of the eyes.
Nineteen serrated, curved teeth lined both sides of the jaw's upper part, but the number of teeth in the lower jaw hasn't been released. Acrocanthosaurus and Giganotosaurus were both surrounded by a massive horizontal ridge along the exterior face of the supragnaular bone that forms the lower jaw, and both had large neural spines in the vertebrae on the back, hips, neck and the upper tail. Some dinosaurs had tall spines on their backs, such as Spinosaurus, which was up to 2 meters (6.6 feet) tall and attached to powerful muscles.