Pity poor T. Rex. What was once the biggest, meanest critter to ever walk the earth was reduced to second place with the discovery of Gigantosaurus. Now, it's even worse:

The biggest, and possibly the baddest predatory dinosaur of them all was not the fabled Tyrannosaurus rex, or even its slightly larger rival Gigantosaurus, but a long-jawed, sail-backed creature called Spinosaurus.

An examination of some newly obtained fossils shows that Spinosaurus stretched an impressive 17 metres from nose to tail, dwarfing its meat-eating relatives. As well as being longer than its rivals, Spinosaurus also had stronger arms with which to catch its prey, unlike the puny-armed T. rex and its ilk.

Of course, they're basing this conclusion on some very fragmentary evidence, so it remains to be seen if new discoveries support it. If they ever make them, that is.