Tyrannosaurus rex

Tyrannosaurus rex

Tyrannosaurus rex skeleton at the Naturalis Biodiversity Center in Leiden, Netherlands

The name Tyrannosaurus rex means "king of the tyrant lizards": "tyranno" means tyrant in Greek; "saurus" means lizard in Greek, and "rex" means "king" in Latin. In 1905, Henry Fairfield Osborn, president of the American Museum of Natural History at the time, named Tyrannosaurus rex.Tyrannosaurus had a much wider range than other tyrannosaurids. Fossils are found in a variety of rock formations dating to the Maastrichtian age of the upper Cretaceous Period, 68 to 66 million years ago.

The neck of Tyrannosaurus rex formed a natural S-shaped curve like that of other theropods, but was short and muscular to support the massive head. The forelimbs had only two clawed fingers, along with an additional small metacarpal representing the remnant of a third digit. In contrast the hind limbs were among the longest in proportion to body size of any theropod. The tail was heavy and long, sometimes containing over forty vertebrae, in order to balance the massive head and torso and to provide space for massive locomotor muscles. To compensate for the immense bulk of the animal, many bones throughout the skeleton were hollowed, reducing its weight without significant loss of strength.