Meet the ‘Wee-rex’. Tiny tyrannosaur is its own species

00:45 The debate around Nanotyrannus

A hotly debated species of dinosaur, assumed by many to be a juvenile T. rex, is actually a separate species, according to new research. Nanotyrannus was a dinosaur anatomically similar to T. rex, but about a tenth of the size, leading many to argue it was a young version of the iconic species. However, examination of the limb bones of a well-preserved Nanotyrannus fossil suggests it was close to finishing its growth and so would never become as large as a T. rex, leading the authors to argue that it is, in fact...