Futalognkosaurus dukei

Futalognkosaurus (that’s not a typo) is a giant titanosaur from the Late Cretaceous of Argentina. Known from a fairly complete type specimen (MUCPv-323), Futalognkosaurus and its closest relatives are called lognkosaurs. As is often the case with giant titanosaur specimens, there has been some debate over the size of Futalognkosaurus, although at around 22 meters (70 feet) it was almost identical in length (and presumably mass) to Dreadnoughtus.