At the end of the Cretaceous period in what is now South America, approximately between 83 and lived 80 million years ago the "Abel's lizard" or Abelisaurus. With a skull up to a meter and sharp teeth this carnivorous predator of between 7 and 9 meters (25 to 30 feet)long and weighed about 3000 kilograms, were living with other predators such as known Tyrannotitan or Carnotauros, fierce competitors for the same prey as old tyrannotitanes patients. The Carnotaurus, was probably a abelisaurid early, scientists assume that Abelisaurus also had front legs short and slender limbs.
The discovery of Abelisaurus is important because it sheds light on many theropods (carnivorous diet and walking biped with three fingers to the front and provided with sharp claws) than the southern hemisphere that were very different from their relatives in the northern hemisphere. This was the result of the separation of land masses of North and South that began in the Jurassic period.
Not go into the morphological differences ... anyone who wants to know them I invite you to search Wikipedia.