Giraffatitan Brancai is a dinosaur that many people have seen, but many are unaware of the dinosaur. For 70 years it was known as a species of Brachiosaurus, & most illustrations of Brachiosaurus are based on a skeleton of Giraffatitan.
Brachiosaurus Altithorax by Elmer Riggs in 1903. Werner Janensch then found a similar fossil in 1914, which he named B. Brancai. In 1988, Gregory Paul realized that B. Altithorax & B. Brancai were not as closely related to each other as previously thought. He elected them to be two subgenera, & in 1917 George Olshevsky proposed B. Brancai to be separated into an entirely new genus, Giraffatitan. It is still widely known as Brachiosaurus, since some argue about the number of differences between fossil finds that necessitate separate genera.
Giraffatitan & its family took a decidedly different shape from most Sauropods. Their front legs were taller than their hind legs, indicating that they held their neck upright. This however, poses the question of whether they were warm-blooded or cold-blooded creatures; multiple hearts would have been required to push cold blood up the neck against gravity, but the head was very small, suggesting it could not have a high enough food-intake for a warm-blooded animal, which would only require one heart.