Tarbosaurus

Tarbosaurus was a very close relative to the Tyrannosaurus rex in size and also the massive skull which is 4 feet long. Tarbosaurus was a large dinosaur about 40 feet long and weighed 6 tons. It lived in Southern Mongolia in the late Cretaceous, 67 million years ago. It was one of the last surviving dinosaurs. New research by scientists suggests that Tarbosaurus is so close to T. rex, that there is still debate on whether or not to move the species T. baatar to the Tyrannosaurus genus.

It is believed that Tarbosaurus was, in fact, T. rex that migrated from North America to Asia through some sort of "land bridge" that connect the two continents during the Late Cretaceous period (around 70-66 million years ago).

More real-life information: Tarbosaurus at Wikipedia.

Jurassic Park
Tarbosaurus has never appeared or mentioned in any Jurassic Park films or books, it has however appeared in Jurassic Park III: Park Builder.

It is possible to make a Tarbosaurus in Jurassic Park: Operation Genesis by copying and modding the file of a Tyrannosaurus rex.