Apatosaurus different dinosaur individuals. Among the many notable differences are the widerand presumably strongerneck of "Apatosaurus" species compared to "B.excelsus". Other species previously assigned to "Apatosaurus", such as "Elosaurus parvus" and "Eobrontosaurus yahnahpin" were also reclassified as "Brontosaurus". Some features proposed to separate "Brontosaurus" from "Apatosaurus" include: posterior dorsal vertebrae with the centrum longer than wide; the scapula rear to the acromial edge and the distal blade being excavated; the acromial edge of the distal scapular blade bearing a rounded expansion; and the ratio of the proximodistal length to transverse breadth of the astragalus 0.55 or greater. Sauropod expert Michael Daniel
Apatosaurus of another "Apatosaurus" individual originally described as "Atlantosaurus immanis"; as a consequence, some elements cannot be ascribed to either specimen with confidence. Marsh distinguished the new genus "Apatosaurus" from "Atlantosaurus" on the basis of the number of sacral vertebrae, with "Apatosaurus" possessing three and "Atlantosaurus" four. Two years later, Marsh announced the discovery of a larger and more complete specimen at Como Bluff, Wyoming. He gave this specimen a new name based on the conventions of his age and the relatively sparse fossil record available at that time. It was later recognised that the features he had used to distinguish