Tyrannotitan (Greek for "giant tyrant"); pronounced tih-RAN-no-tie-tan
Woodlands of South America
Middle Cretaceous (120-110 million years ago)
Size and Weight:
About 40 feet long; weight unknown
Enormous size; small arms
In the paleontology game, it sometimes helps to stake out an impressive name before releasing the full details of your research--and no name is more impressive than Tyrannotitan, which makes Tyrannosaurus Rex seem wimpy by comparison. The partial skeleton of this allosaur, a type of large theropod closely related to Allosaurus, was discovered in 2005, in South America, and is still being analyzed; for now, suffice it to say that Tyrannotitan appears to have been one of the largest carnivores ever to roam the planet, and was closely related to its fellow giant theropods Carcharodontosaurus and Giganotosaurus. (Despite its name, Tyrannotitan wasn't a true tyrannosaur, a subset of theropod dinosaurs characterized by their small arms and big heads, among other features.)
Of course, it's always possible that--upon closer analysis--the "type specimen" of Tyrannotitan will turn out to belong to one of the above-named predators. In that case, the name Tyrannotitan will become available again, and can be assigned to the next giant meat-eating dinosaur that merits its own genus.