MEANING: Tyrant lizard
PERIOD: Late Cretaceous
CONTINENT: North America
Tyrannosaurus is a large North American theropod, and the last known tyrannosaurid living before the end-Cretaceous extinction event. One of the largest land carnivores of all time, Tyrannosaurus grew to about 12 m long, weighing up to 9 t. The massive skull bones were fused and pneumatized, allowing for an extremely powerful bite. The tip of the snout was U-shaped, which increased the amount of tissue a tyrannosaur could bite off its prey. The skull of Tyrannosaurus was wide at the rear but had a narrow snout, allowing unusually good binocular vision. It was likely both an active predator and a scavenger, but the specifics of its feeding behavior and lifestyle are still debated.
Tyrannosaurus is from the Cretaceous. The Cretaceous is a geological period that lasted from about 145 to 66 million years ago. It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of the entire Phanerozoic. The name is derived from the Latin creta, "chalk", which is abundant in the latter half of the period.
The Cretaceous was a period with a relatively warm climate, resulting in high eustatic sea levels that created numerous shallow inland seas. These oceans and seas were populated with now-extinct flora and fauna, while dinosaurs continued to dominate on land. The world was ice free, and forests extended to the poles. During this time, new groups of mammals and birds appeared. During the Early Cretaceous, flowering plants appeared and began to rapidly diversify, becoming the dominant group of plants across the Earth by the end of the Cretaceous, coincident with the decline and extinction of previously widespread gymnosperm groups.
The Cretaceous (along with the Mesozoic) ended with the Cretaceous–Paleogene extinction event, a large mass extinction in which many groups, including non-avian dinosaurs, pterosaurs, and large marine reptiles, died out. The end of the Cretaceous is defined by the abrupt Cretaceous–Paleogene boundary (K–Pg boundary), a geologic signature associated with the mass extinction that lies between the Mesozoic and Cenozoic Eras.
Tyrannosaurus is a tyrannosaurid. Tyrannosauridae is a family of theropod dinosaurs known for often being the largest predators in their ecosystems, at the top of the food chain. They lived near the end of the Cretaceous Period in North America and Asia. Tyrannosaurids were bipedal carnivores with massive skulls and large teeth. Their long legs were proportioned for fast movement, but their arms were very small, and only had two functional digits.