New study settles 40-year debate: Nanotyrannus is a new species

For four decades, a frequently acrimonious debate has raged in paleontological circles about the correct taxonomy for a handful of rare fossil specimens. One faction insisted the fossils were juvenile Tyrannosaurus rex; the other argued that they represented a new species dubbed Nanotyrannus lancensis. Now, paleontologists believe they have settled the debate once and for all due to a new analysis of a well-preserved fossil.

The verdict: It is…