Are you a fan of the Nanotyrannus, the three-horned Torosaurus, or the Dracorex hogwartsia, named for the famed school of wizardry? Then paleontologists have some bad news: these and roughly a third of other recorded dinosaur species probably never existed.
Many dinosaur species are experiencing a second extermination — death by reclassification. Thanks to new technologies that allow paleontologists to analyze the tissues in dinosaur fossils, many paleontologists are discovering that dinosaurs we once thought of as separate species are actually part of the same species, simply at different stages of their development. For example the Nanotyrannus, supposedly a diminutive cousin of the Tyrannosaurus Rex is probably just a juvenile version of the latter species. Similarly, the Torosaurus and the Dracorex hogwartsia have been stricken from the books, as they are likely members of previously discovered species.
In this week's issue of PLoS, Jack Horner of the Museum of the Rockies at Montana State University in Bozeman estimates that a third of dinosaur species currently listed are actually members of other speicies. So how were these creatures mislabeled for so long? As paleontologists are better able to determine the growth stage of dinosaur fossils, they are finding that many species retain their juvenile characteristics longer than previously believed, and as dinosaurs age, their characteristics undergo drastic changes.
So, Hogwarts may be losing its dinosaur, but its parent species, Pachycephalosaurus wyomingensis, is gaining a child.