Remains of this dinosaur are rare, but have been found in Colorado, Oklahoma, Utah, and Wyoming. At the time, it appeared to be the largest-known dinosaur it was named Brachiosaurus altithorax, meaning “high-chested arm reptile,” in 1903. Riggs, who had excavated the skeleton during the previous year.
In 1901, it was described in a report by paleontologist Elmer S. The specimen consisted of a partial skeleton, lacking a head, but was immediately recognizable for its distinctive anatomical features. It was first discovered near Fruita, Colorado in 1900, a location that is now part of the Morrison Formation. The first of these two to be discovered was Brachiosaurus its name means “arm reptile,” in reference to its characteristically long forelimbs.
The closely related genus Giraffatitan, which most popular depictions of Brachiosaurus are based on, lived during a slightly broader span of time ranging from 150 to 145 million years ago. Brachiosaurus is a genus of extremely large sauropod dinosaur in the family Brachiosauridae known from the late Jurassic period, 154 to 153 million years ago.