page_title: Bistahieversor
section_title: Description
hierarchical_section_title: Bistahieversor / Description
caption_attribution_description: English: Estimated size of the theropod dinosaur Bistahieversor sealeyi,&#91;1&#93; compared to a human. Size of the holotype (NMMNH P-27469) based on the size of the skull, with body proportions based on the closely related Tyrannosauridae. Size of the juvenile P-25049 based on size estimation from [New Mexico Museum of Natural History and Science], based on the known fossil pieces.&#91;2&#93; References ↑ Carr, T. D. and Williamson, T.E. (2000). "A review of Tyrannosauridae (Dinosauria: Coelurosauria) from New Mexico." New Mexico Museum of Natural History and Science Bulletin, 17: 113–145. ↑ http://image58.webshots.com/158/2/24/32/2340224320051262496GkQeJl_fs.jpg.
context_page_description: Bistahieversor, also known as the "Bisti Beast", is a genus of eutyrannosaurian tyrannosauroid dinosaur; the genus contains only a single known species, B. sealeyi, described in 2010, from the Late Cretaceous Hunter Wash member of the Kirtland Formation, which has been dated to 74.55 ± 0.29 Ma.
  The name Bistahieversor comes from the Navajo Bistahí, or "place of the adobe formations" in reference to the Bisti/De-Na-Zin Wilderness where it was found, and eversor, meaning "destroyer."
context_section_description: Material from both adolescent and adult individuals has been found in the Kirtland Formation of New Mexico, United States. Adult Bistahieversor are estimated to have been around 9 meters (30 ft) long, weighing at least a ton. The snout is deep, indicating that the feature is not unique to more derived tyrannosaurs such as Tyrannosaurus. Geographical barriers such as the newly forming Rocky Mountains may have isolated the more southerly Bistahieversor from more derived northern tyrannosaurs. In 2010 Gregory S. Paul estimated a length of 8 m (26 ft) and a weight of 2.5 tonnes (2.75 short tons). In 2016 Molina-Pérez and Larramendi gave a length of 9 m (29.5 ft) and a weight of 3.3 tonnes (3.6 short tons).
  Bistahieversor differs from other tyrannosaurs in the possession of 64 teeth, an extra opening above the eye, and a keel along the lower jaw. The opening above the eye is thought to have accommodated an air sac that would have lightened the skull's weight. Bistahieversor also had a complex joint at its "forehead" that would have stabilized the skull, preventing movement at the joint.
caption: Size comparison with a juvenile
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