meaning 'tyrant lizard' is a genus of theropod dinosaur.
The species Tyrannosaurus rex, commonly abbreviated to T.
rex, is one of the dinosaurs most often featured in popular
culture around the world. It hails from what is now western
North America. Some scientists consider Tarbosaurus bataar
from Asia to represent a second species of Tyrannosaurus,
while others maintain Tarbosaurus as a separate genus.
other tyrannosaurids, Tyrannosaurus was a bipedal carnivore
with a massive skull balanced by a long, heavy tail. Relative
to the large and powerful hindlimbs, Tyrannosaurus forelimbs
were small and retained only two digits. Although other
theropods rivaled or exceeded T. rex in size, it was the
largest known tyrannosaurid and one of the largest known
land predators, measuring over 13 metres (43 feet) in length
and up to 6.8 metric tons (7.5 short tons) in weight.
of T. rex have been found in North American rock formations
dating to the last three million years of the Cretaceous
Period at the end of the Maastrichtian stage, approximately
68.5 to 65.5 million years ago; it was among the last dinosaurs
to exist prior to the Cretaceous-Tertiary extinction event.
More than 30 specimens of T. rex have been identified, some
of which are nearly complete skeletons. Some researchers
claim to have discovered soft tissue as well. The abundance
of fossil material has allowed significant research into
many aspects of its biology, including life history and
biomechanics. The feeding habits, physiology and potential
speed of T. rex are a few of the topics which remain controversial.