For more than a century the brontosaurus (photo ©Elika & Shannon) was considered a species of the genus Apatosaurus classified as Apatosaurus excelsus. The name brontosaurus kept on being commonly used but in the field of paleontology it was believed to be an Apatosaurus. However, now a group of scientists published the results of a very thorough search on the online magazine “PeerJ” which explains why the brontosaurus make an independent genus.

The first brontosaurus fossils were found in the 1870s in the USA, in the same years in which the first fossils of Apatosaurus were found. The problem in the classification of these sauropods was caused by the fact that several skeletons were only partial. This made it difficult to accurately assess their characteristics to recognize the various relations.

Initially, one of the skeletons was named Apatosaurus ajax and another was called Brontosaurus excelsus, which means “thunder lizard”. The situation became more complicated in 1899, when some paleontologists found a skeleton with characteristics that appeared intermediate between the two previous ones. For this reason, in 1903 it was decided that they were different species of the same genus.

The genus Apatosaurus was the one defined first so it had the precedence. The consequence was that the brontosaurus was reclassified as Apatosaurus excelsus. However, the exposure of the fossils available and various reconstructions of the animal had been so wide that the name Brontosaurus kept on being used.

However, now a new study by Emanuel Tschopp, Octavio Mateus and Roger B.J. Benson could change again the classification of the brontosaurus. In nearly 300 pages of analysis in which they compare 477 morphological characteristics of sauropod fossils, the researchers explain why the brontosaurus was distinct from the apatosaurus.

This research used the discoveries of dinosaurs similar to the brontosaurus and the apatosaurus occurred in recent years. This made it possible to carry out a new investigation to analyze the similarities and differences among them. The researchers applied a statistical approach to calculate the differences between dinosaurs of the family of diplodocids (Diplodocidae) to which brontosaurus and apatosaurus belong.

The result is that the researchers believe that the brontosaurus constitutes a distinct genus from the apatosaurus. In the field of paleontology, the discovery of new fossils and new analysis techniques can lead at any time to new discoveries and classification changes. These are things that happen often but the case of the brontosaurus inevitably makes the news more than others.

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