APATOSAURUS
Apatosaurus used to be called "Brontosaurus," which
meant "thunder lizard" and referred to the loud 
noise
this enormous dinosaur must have made as its 33-ton body lumbered across
the plains of North America. Scientists no longer use the name however
because the first fossils to be discovered of this creature were actually
given the name Apatosaurus.
Apatosaurus was one of the largest animals ever to walk the earth. It belonged to the group of plant-eating Sauropods that included Diplodocus and Camarasaurus. Like these other dinosaurs, Apatosaurus had a very long neck and even longer tail. An adult measured up to 70 feet in length and had a tiny head in comparison to its body: only 22 inches long! Although not as long as its close relative Diplodocus, Apatosaurus weighed nearly three times as much, mainly because its bones were denser and its heavy tail was made up of almost 82 interlocking vertebrae.