Apatosaurinae

Apatosaurinae (from Ancient Greek words ἀπάτη (apátē), meaning "deception", and σαῦρος (saûros), meaning "lizard") is a subfamily of diplodocid sauropods, an extinct group of large, quadrupedal dinosaurs, the other subfamily in Diplodocidae being Diplodocinae. Apatosaurines are distinguished by their more robust, stocky builds and shorter necks proportionally to the rest of their bodies. Several fairly complete specimens are known, giving a comprehensive view of apatosaurine anatomy.

The subfamily includes only two genera for certain, Apatosaurus and Brontosaurus, according to a 2015 study, though Amphicoelias and a species of Atlantosaurus may also belong to this group. All members are known from the Late Jurassic-aged Morrison Formation of the American West, dating to between 157 and 146.8 million years ago. Fossils were first unearthed in 1877 by crews working for American paleontologist Othniel Charles Marsh in the midst of the Bone Wars, a fossil-hunting rivalry with naturalist Edward Drinker Cope. Marsh went on to name both genera of apatosaurine; Apatosaurus in 1877 and Brontosaurus in 1879. For many years, Brontosaurus was considered a taxonomic synonym of Apatosaurus after a 1903 study by paleontologist Elmer Riggs considered them synonyms. This was the prevalent notion until a 2015 paper led by Emmanuel Tschopp argued that the two were separate genera, however some authors still consider the two synonyms. According to Tschopp and colleagues, there are six valid species of apatosaurine; three in Brontosaurus and two in Apatosaurus.