GiganotosaurusCredit: Joe Tucciarone Giganotosaurus was 47 feet long and weighed 8 tons. It lived 95 million years ago. It was not the biggest carnivore ever, though. That credit goes to Spinosaurus, thought to reach 55 feet in length.
Hylonomus is an extinct genus of reptile that lived 312 million years ago during the Late Carboniferous period. Hylonomus was 20 centimetres in) long (including the tail) and probably would have looked rather similar to modern lizards.