A paper in this week's edition of PloS One is disappointing news for small boys and palaeontologists, or anyone who's a dinosaur fan. According to a study by Mark Goodwin and Jack Horner, it appears that we may have significantly over-inflated the number of different dinosaur species.
Goodwin and Horner have been looking at dome-headed dinosaurs from North America, known as pachycephalosaurs – they have heads like bowling balls. They've been collecting fossils in Hell Creek, Montana for 11 years, doing a detailed analysis of different species of dinosaur fossils, using techniques like CT scanning and analysis of bone structure.
Horner and Goodwin compared fossils of pachycephalosaurus with another domeheaded dinosaur found in Montana, and a dragon-like skull unearthed in South Dakota, named Dracorex hogwartsia – yes, after Harry Potter's school.
The scientists think that rather than being three different species, the dinosaurs are all actually from the same species, but are just at different stages of sexual maturity. They confirmed their findings by looking at another 17 dino skulls from North America.
This suggests we need to have a drastic rethink about what actually constitutes a dinosaur species. It seems that much of the confusion has crept in because juvenile dinosaurs can look quite different from grownups of the same species, due to the development of head ornaments like horns, domes and spikes. But scientists may have confused these superficial features with more important underlying similarities between fossils, missing the fact that they are actually the same species.
Horner and Goodwin reckon that up to a third of all named dinosaur species may actually never have existed, and may just be juvenile forms of another species. Other scientists have also suggested this, as a species called Torosaurus was recently dismissed as being a juvenile version of another species, while a number of duck-billed dinosaurs and the fantastically named Nanotyrannus – thought to be a mini T rex – may not be separate species.
So sadly for dino-fans, some of those wonderful names may have to be consigned to the taxonomic dustbin.