Acrocanthosaurus- meaning "high-spined lizard") is a genus of theropod dinosaur that existed in what is now North America during the Aptian and early Albian stages of the Early Cretaceous. Like most dinosaur genera, Acrocanthosaurus contains only a single species, Its fossil remains are found mainly in the U.S. states of Oklahoma, Texas, and Wyoming, although teeth attributed to Acrocanthosaurus have been found as far east as Maryland.
Acrocanthosaurus was a bipedal predator. As the name suggests, it is best known for the high neural spines on many of its vertebrae, which most likely supported a ridge of muscle over the animal's neck, back and hips. Acrocanthosaurus was one of the largest theropods, approaching 12 meters (40 ft) in length, and weighing up to 6.2 tonnes (6.8 short tons). Large theropod footprints discovered in Texas may have been made by Acrocanthosaurus, although there is no direct association with skeletal remains.
Acrocanthosaurus was the largest theropod in its ecosystem and likely an apex predator which possibly preyed on large sauropods and ornithopods.Although slightly smaller than gigantic relatives like Giganotosaurus, Acrocanthosaurus was still among the largest theropods ever to exist. The largest known specimen is estimated to have measured 11.5 meters (38 ft) from snout to tail tip and weighed 5.7 t (6.3 short tons) to 6.2 t (6.8 short tons),though Bates et al. (2009) noted that a weight of 7 t (7.7 short tons) is not impossible for this specimen. Its skull alone was nearly 1.3 meters (4.3 ft) in length.