Barnum Brown, assistant curator of the American Museum of Natural History, found the first partial skeleton of T. rex in eastern Wyoming in 1900.
Brown found another partial skeleton in the Hell Creek Formation in Montana in 1902, comprising approximately 34 fossilized bones.
Writing at the time Brown said "Quarry No.
1 contains the femur, pubes, humerus, three vertebrae and two undetermined bones of a large Carnivorous Dinosaur not described by Marsh.... I have never seen anything like it from the Cretaceous".
Henry Fairfield Osborn, president of the American Museum of Natural History, named the second skeleton T. rex in 1905.
The generic name is derived from the Greek words τύραννος (tyrannos, meaning "tyrant") and σαῦρος (sauros, meaning "lizard").
Osborn used the Latin word rex, meaning "king", for the specific name.
The full binomial therefore translates to "tyrant lizard the king" or "King Tyrant Lizard", emphasizing the animal's size and perceived dominance over other species of the time.

Osborn named the other specimen Dynamosaurus imperiosus in a paper in 1905.
In 1906, Osborn recognized that the two skeletons were from the same species and selected Tyrannosaurus as the preferred name.
The original Dynamosaurus material resides in the collections of the Natural History Museum, London.
In 1941, the T. rex type specimen was sold to the Carnegie Museum of Natural History in Pittsburgh, Pennsylvania, for $7,000.
Dynamosaurus would later be honored by the 2018 description of another species of tyrannosaurid by Andrew McDonald and colleagues, Dynamoterror dynastes, whose name was chosen in reference to the 1905 name, as it had been a "childhood favorite" of McDonald's.

From the 1910s through the end of the 1950s, Barnum's discoveries remained the only specimens of Tyrannosaurus, as the Great Depression and wars kept many paleontologists out of the field.
Barnum Brown, assistant curator of the American Museum of Natural History, found the first partial skeleton of T. rex in eastern Wyoming in 1900. Brown found another partial skeleton in the Hell Creek Formation in Montana in 1902, comprising approximately 34 fossilized bones. Writing at the time Brown said "Quarry No. 1 contains the femur, pubes, humerus, three vertebrae and two undetermined bones of a large Carnivorous Dinosaur not described by Marsh.... I have never seen anything like it from the Cretaceous". Henry Fairfield Osborn, president of the American Museum of Natural History, named the second skeleton T. rex in 1905. The generic name is derived from the Greek words τύραννος (tyrannos, meaning "tyrant") and σαῦρος (sauros, meaning "lizard"). Osborn used the Latin word rex, meaning "king", for the specific name. The full binomial therefore translates to "tyrant lizard the king" or "King Tyrant Lizard", emphasizing the animal's size and perceived dominance over other species of the time. 
Osborn named the other specimen Dynamosaurus imperiosus in a paper in 1905. In 1906, Osborn recognized that the two skeletons were from the same species and selected Tyrannosaurus as the preferred name. The original Dynamosaurus material resides in the collections of the Natural History Museum, London. In 1941, the T. rex type specimen was sold to the Carnegie Museum of Natural History in Pittsburgh, Pennsylvania, for $7,000. Dynamosaurus would later be honored by the 2018 description of another species of tyrannosaurid by Andrew McDonald and colleagues, Dynamoterror dynastes, whose name was chosen in reference to the 1905 name, as it had been a "childhood favorite" of McDonald's.
From the 1910s through the end of the 1950s, Barnum's discoveries remained the only specimens of Tyrannosaurus, as the Great Depression and wars kept many paleontologists out of the field.
Tyrannosaurus