Apatosaurus was a member of the sauropod family of dinosaurs and was a common and almost instantly recognizable dinosaur in Dinotopia. It could be found almost anywhere on the entire island and was one of the island's largest dinosaurs.
Apatosaurus is derived from the Greek apate/apatelos, meaning "deception/deceptive" and sauros, meaning "lizard." It has also been know by the scientifically redundant name Brontosaurus.
They commonly drew large carts and would take part in convoys across the dangerous Rainy Basin, where they would wear armor to protect them from the carnosaurs that lived there.
Apatosaurs had long necks, stout bodies, and long whip-like tails that could be used in defense-such as Koro Kidinga defending herself against Tyrannosaurs. Their forelimbs were slightly shorter than their hind-limbs. The neck was extremely long and had a system of interconnected air sacs inside that helped reduce its weight. They also had extremely long ribs, giving them a large and very deep chest. Unlike its close cousin Diplodicus, Apatosaurus had longer and more robust legs.
Their skull was small in comparison to the body and was filled with chisel-shaped teeth, perfect for their diet of plants.
Apatosaurs tended to travel and migrate in herds, though they were slightly more solitary than most sauropods.
Apatosaurs are classified in the subfamily Apatosaurinae and in the family Diplodocidae. They are closely related to Diplodicus.