"Thunder Lizard" in Greek) is an extinct genus of apatosaurian sauropod dinosaur which lived throughout North America during the late Jurassic period, approximately 155 to 145 million years ago. It was originally considered to be a junior synonym of Apatosaurus, but is know regarded as a separate taxon after extensive scientific exploration conducted in 2015 revealed their were substantial differences between the two genera (for example, Brontosaurus can be defined as having a slimer build and slightly smaller in size).
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