Diplodocus now common scientific opinion that "Seismosaurus hallorum" is a species of "Diplodocus". This genus of dinosaurs lived in what is now mid-western North America at the end of the Jurassic period. "Diplodocus" is one of the more common dinosaur fossils found in the middle to upper Morrison Formation, between about 154 and 152 million years ago, during the late Kimmeridgian age. The Morrison Formation records an environment and time dominated by gigantic sauropod dinosaurs, such as "Apatosaurus", "Barosaurus", "Brachiosaurus", "Brontosaurus", and "Camarasaurus". "Diplodocus" is among the most easily identifiable dinosaurs, with its typical sauropod shape, long neck and tail, and
Barosaurus might have favoured those with longer necks. (See video "Neck Impossible" at reference.) Books: Barosaurus Barosaurus ( ) was a giant, long-tailed, long-necked, plant-eating dinosaur closely related to the more familiar "Diplodocus". Remains have been found in the Morrison Formation from the Upper Jurassic Period of Utah and South Dakota (and possibly Africa, as exemplified by the Kadsi Formation). It is present in stratigraphic zones 2-5. The composite term "Barosaurus" comes from the Greek words "barys" (βαρυς) meaning "heavy" and "sauros" (σαυρος) meaning "lizard"; thus "heavy lizard". "Barosaurus" was an enormous animal, with some adults measuring more than 26 meters