Simplify the following text for a Grade 9 native English-speaking person.
Original: Quinkana is an extinct genus of mekosuchine crocodile that lived in Australia from ~ 24 million years ago to ~ 40,000 years ago .
Simplified: Quinkana is a extinct genus of large land crocodile that reached up to lengths of 7m , that lived in Australia from 24 million years ago to 40,000 years ago .