Bistahieversor Facts
| Diet | Carnivore |
| Height | 3m |
| Length | 9m |
| Weight | 2.5 tonnes |
| Environment | Land |
| Era | Cretaceous |
| Period | Late Cretaceous |
| Type | Theropod |
| Location | North America |

| Diet | Carnivore |
| Height | 3m |
| Length | 9m |
| Weight | 2.5 tonnes |
| Environment | Land |
| Era | Cretaceous |
| Period | Late Cretaceous |
| Type | Theropod |
| Location | North America |
Bistahieversor, known as the 'Bisti Beast', was a fearsome theropod dinosaur that prowled the ancient landscapes of what is now New Mexico during the Late Cretaceous period. This powerful predator lived approximately 75.5 to 74.5 million years ago, making it one of the earlier relatives of the famous Tyrannosaurus rex. Despite being smaller than its later cousins, Bistahieversor was still a formidable hunter that dominated its ecosystem.
Measuring around 9 metres in length and standing about 3 metres tall at the hip, Bistahieversor possessed the classic theropod build of a bipedal predator. It had powerful hind legs for chasing prey, relatively small arms, and a massive skull filled with sharp, serrated teeth designed for tearing flesh. Its robust build suggests it was well-adapted for taking down large prey in the diverse Late Cretaceous ecosystems of ancient North America.
As a carnivore, Bistahieversor likely hunted the various herbivorous dinosaurs that shared its habitat, including hadrosaurs and ceratopsians. Its strong jaw muscles and blade-like teeth would have made it an efficient killer, capable of delivering devastating bites to its prey. The discovery of both adult and juvenile specimens has provided valuable insights into how these theropods grew and developed.
Bistahieversor represents an important piece in understanding the evolution of large theropod dinosaurs in North America. Its fossils, found in the Kirtland and Fruitland Formations of New Mexico, help fill gaps in our knowledge of tyrannosaur evolution and demonstrate the diversity of predatory dinosaurs that existed before T. rex became the apex predator of its time.
Bistahieversor had a robust skull with powerful jaw muscles and sharp, serrated teeth typical of tyrannosaur relatives. It possessed the characteristic theropod body plan with strong hind legs, small arms, and a long tail for balance, though it was notably smaller than later tyrannosaurs like T. rex.
Bistahieversor was likely an active predator that hunted large herbivorous dinosaurs in its ecosystem. Evidence from both adult and juvenile specimens suggests these theropods may have had complex growth patterns, with young individuals possibly occupying different ecological niches than adults.
| Phylum | Chordata |
| Class | Saurischia |
| Order | Avetheropoda |
| Genus | Bistahieversor |
Bistahieversor was first described by Thomas Carr and Thomas Williamson in 2010. The original fossils were discovered at Kirtland Formation, New Mexico, USA.