So you're still a bit off in your Brontosaurus story.
Brontosaurus and Apatosaurus are not the same animal. In fact, Brontosaurus never was an animal.
It is correct that what was originally called 'Brontosaurus' was an Apatosaurus skeleton with a Camarasaurus skull (clearly the wrong type of skull, even). When a correct 'Brontosaurus' skull was placed upon the model to correct the error, it was shortly thereafter discovered that the animal in question had been named 'Apatosaurus' in the scientific literature a scant few years before it was named 'Brontosaurus'.
The latter name was simply published in a more prominent journal and, as is often the case, it was overlooked for years that the same genus was being described. Law of primacy of naming within the scientific community gave prevalence to 'Apatosaurus' at that point, in the late 80's, I believe.
Sometimes the law of primacy isn't, in fact, followed. In this case it was. It doesn't seem as much like a law as an arbitrary decision. A case in point is that of the red imported fire ant, which, being the most intensely studied insect in the field of entomology, has thus far continued to keep its incorrect, though more popular, name.