Apatosaurus Excelsus, commonly known as the Brontosaurus, was a massive, herbivorous dinosaur that roamed the Earth during the Late Jurassic period. Some of the synonyms used to refer to this creature include Apatosaurus Ajax, Apatosaurus Amplusr, Apatosaurus Grandis and Apatosaurus Louisae. The name Apatosaurus is derived from Greek words meaning "deceptive lizard," while Excelsus means "high." The Brontosaurus was known for its long neck and tail, stout legs, and enormous size, reaching lengths of up to 75 feet and weighing around 25-38 tons. Despite its impressive appearance, this gentle giant was a peaceful herbivore, feeding mostly on plants and shrubs.