Tyrannosaurus Rex, often abbreviated as T. Rex, derives its name from the Greek words meaning "tyrant lizard" and the Latin term for "king". This iconic dinosaur is one of the most well - known carnivorous dinosaurs ever discovered, recognized as the largest, most powerful, and latest - appearing carnivorous dinosaur species.
Physical Characteristics
T. Rex was an imposing creature. On average, it measured about 13 meters in length and stood around 5 meters tall at the shoulder, with an average weight of approximately 9 tons. The average adult individuals in the population ranged from 11 to 12 meters long. Its head alone was quite large, typically 1.45 to 1.55 meters, and some fossil evidence suggests that larger skulls could reach up to 1.75 meters.
The dinosaur had a heavy, high, and laterally flattened skull. A notable feature was its forward - facing eyes, which gave it stereoscopic vision and excellent eyesight. There were two large antorbital fenestrae on the skull, and the eye sockets were oval - shaped. T. Rex had extremely well - developed teeth. Traces of strong ligaments that fixed the bones could be found between the dentary, condylar bone, and prearticular bone.
It had a relatively short neck consisting of 9 cervical vertebrae, which were short and wide. The shoulder girdle was reduced. Although its forelimbs were small, the scapula was large - larger even than that of the Therizinosaurus. For example, the scapula of FMNH PR 2081 was 114 centimeters long, while its humerus was only 39 centimeters, less than half the length of the scapula. Like other tyrannosaurids, T. Rex was a bipedal carnivore with a large skull and a long, heavy tail that helped it maintain balance.
Habitat and Time Period
T. Rex lived during the last 3 million years of the Maastrichtian stage in the Late Cretaceous period, approximately 68.5 to 65.5 million years ago. It was one of the last dinosaur species before the Cretaceous - Paleogene extinction event. Fossils of T. Rex have been found in the western parts of the United States and Canada in North America, and its distribution range was wider than that of other tyrannosaurids.
Fossil Discoveries
As of today in 2013, more than 50 T. Rex specimens have been identified, including several with a high degree of completeness. When private collections are included, the number of T. Rex specimens, excluding isolated teeth fossils, reaches hundreds. This abundant fossil material has allowed scientists to conduct in - depth research on various aspects of T. Rex's physiology, such as its growth patterns and biomechanics. Some researchers have even discovered soft tissues and proteins from these fossils.
Classification Controversies
There are some classification debates surrounding T. Rex. Some scientists believe that Tarbosaurus bataar from Asia is the first valid species of the Tyrannosaurus genus, while others consider Tarbosaurus to be an independent genus. In addition, many species of tyrannosaurids have been proposed, but most of them are regarded as synonyms of T. Rex or classified into other genera.
Ongoing Debates
Despite extensive research, some aspects of T. Rex remain controversial. Its feeding habits, physiological functions, and movement speed are still topics of discussion among scientists.
Extinction
T. Rex went extinct during the Cretaceous - Paleogene mass extinction event 65 million years ago, marking the end of this mighty dinosaur's reign on Earth.
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