Diplodocus is a sauropod likely to appaer in a future update.
In Real Life
It is estimated to have weighed from 10-16 tonnes (11-18 tons). Its body length may have reached up to 27 meters (89 feet) in length, including the tail, which was incredibly long. Seismosaurus, one of the longest dinosaurs (though far from the heaviest or tallest) is believed to be synonymous with it.
Behind The Scenes
A Diplodocus is shown being attacked by a pack of Allosaurus in the Allosaurus dossier. This could mean it is coming to the game someday. However, it is possible that this picture represents the jurassic period, the time period in which both species existed in.