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
Jurassic epochs: Early, Middle, and Late. Similarly, in stratigraphy, the Jurassic is divided into the Lower Jurassic, Middle Jurassic, and Upper Jurassic series of rock formations, also known as "Lias", "Dogger" and "Malm" in Europe. The separation of the term Jurassic into three sections originated with Leopold von Buch. The faunal stages from youngest to oldest are: During the early Jurassic period, the supercontinent Pangaea broke up into the northern supercontinent Laurasia and the southern supercontinent Gondwana; the Gulf of Mexico opened in the new rift between North America and what is now Mexico's Yucatan Peninsula. The Jurassic North Atlantic Ocean