The brontosaurus -- the most famous of all dinosaurs, the emblem for Sinclair gas and the model for the Flintstone's Dino -- never existed. O.C. Marsh somehow got some head's mixed up and what he thought was a new type of lizard was really just the previously discovered apatosaurus. So, order of discovery takes precedence over fame of name.
I just point this out to illustrate the dangers of depending too much on the reliability of the fossil record.
The brontosaurus -- the most famous of all dinosaurs, the emblem for Sinclair gas and the model for the Flintstone's Dino -- never existed. O.C. Marsh somehow got some head's mixed up and what he thought was a new type of lizard was really just the previously discovered apatosaurus. Thus we call the animal the apatosaurus today, yes. The animal existed. Does the species we call "dog" exist, or is it just what the Romans used to call "canis?"
The answer is "yes." It's not and either-or question.