The Land Before Time tells the story of an orphaned sauropod.
Brontosaurus ( [ ˌbrɒntəˈsɔːrəs ] ) , meaning `` thunder lizard '' ( from Greek βροντή , brontē = thunder + σαῦρος , sauros = lizard ) , is a genus of gigantic quadruped sauropod dinosaurs . The Land Before Time . The plot concerns a young Brontosaurus named Littlefoot who is orphaned when his mother is killed by a Tyrannosaurus .