The Brontosaurus, sometimes called the thunder lizard, has long been considered misclassified, the remains misinterpreted and the dinosaur misnamed.

In short, the scientists told us it didn't really exist. Its bones were mistaken for something new. The scientific community has since 1903 believed the genus Brontosaurus was in fact the Apatosaurus.

However, an exhaustive study by palaeontologists from Portugal and the UK provides compelling evidence that Brontosaurus is distinct from Apatosaurus and as such, can now be reinstated as its own unique genus.

Brontosaurus has inspired generations of children thanks to its size and name.

In 1903 it was decided that the differences between Brontosaurus excelsus and Apatosaurus were so minor that it was better to put them both in the same genus. Because Apatosaurus was named first, it was the one that was used under the rules of scientific naming.

In a study published in the journal PeerJ, palaeontologists Emanuel Tschopp, Octávio Mateus, and Roger Benson say that Brontosaurus was a unique genus all along.

"Our research would not have been possible at this level of detail 15 or more years ago," says Tschopp.

"In fact, until very recently, the claim that Brontosaurus was the same as Apatosaurus was completely reasonable, based on the knowledge we had."

It is only with numerous findings of dinosaurs similar to Apatosaurus and Brontosaurus in recent years that it has become possible to do a detailed reinvestigation of how different they actually were.

The researchers applied statistical approaches to calculate the differences between other species and diplodocid dinosaurs and were surprised by the result.

"The differences we found between Brontosaurus and Apatosaurus were at least as numerous as the ones between other closely related genera, and much more than what you normally find between species," says Benson, a co-author from the University of Oxford.

This article was originally published by Business Insider.

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