Mapusaurus was an Allosaur from middle Cretaceous Argentina. Its size has been debated, even thought it has been found by fairly good fossil remains. A family of seven where found together, two adults, two teenagers, and two childeren. It was 46 feet long and holds a place in the top 10 biggest dinosaurs (depending on who you ask). It was lighter then Giganotosaurus, and was only 6 tons. Also, it is believed that Mapusaurus evolved from Giganotosaurus, meaning that it would be faster and smarter than its larger cousin.