Before mankind left the jungles of Africa, Australia harbored a monster. A giant goanna, the largest land lizard of all time. This was Megalania, a dragon of the bush that reached the size of a crocodile. When the ancestors of Australia's aboriginees arrived on their new, strange continent, they would have had to deal with this immense reptile, and more than a few undoubtedly vanished down its gullet. However, these new people brought Megalania's doom, for the giant kangaroos and wombat-like diprotodonts that Megalania relied on for its tucker were poorly equiped to evade the spears of mankind. With the extinction of its prey, Megalania was not far behind. Its smaller relatives are our only reminder of this once magnificent ruler of the land down under.
Megalania is the only land lizard which ever reached the sheer mass to be considered Immense under the goanna size classification presented on these pages. Smaller Megalania were more common, however, and a typical ancient aussie dragon would be merely Giant or Humongus. Note that this is a fairly conservative estimate of this lizard's size, some paleontologists estimate Megalania could have exceeded a ton in mass.