The word Brontosaurus appears in the hunspell dictionary, but Apatosaurus does not. Scientifically, Brontosaurus is not correct, though it is in common usage. Apatosaurus is the correct name, and its use should not be discouraged. Webster's defines both. Ideally (in my mind) Brontosaurus should be removed from the dictionary and Apatosaurus added. At the least Apatosaurus should be added.
This causes Thunderbird, for instance, to correct Apatosaurus to Brontosaurus, as seen in the attached screenshot.