a very large amphibious herbivorous dinosaur of the genus Apatosaurus (also known as Brontosaurus), having a long neck and tail and a relatively small head, existing in parts of North America in the late Jurassic period.
a very large amphibious herbivorous dinosaur of the genus Apatosaurus (also known as Brontosaurus), having a long neck and tail and a relatively small head, existing in parts of North America in the late Jurassic period.