Location : N. America

Haplocanthosaurus was a large, long-necked plant eater that roamed the western part of the United States near the end of the Jurassic period. Although many Haplocanthosaurus bones have been discovered, scientists still haven't found a skull so they can't be absolutely certain what this giant looked like. Because of this, it still can't be placed in the correct family of sauropods.

The most common association of this dinosaur is with the cetiosaurs. It has also been suggested, however, that it may have been a primitive titanosaur, or even a diplodocid. Currently, there are three species recognized for this genus.