Okay, so the title might be a little hyperbolic, but I’m still astounded by what has just been published. I don’t normally post about the latest discoveries, as there are already others who do it better than I could, but this one triggered such a strong reaction that I have to write about it. Basically, a new paper has been published proposing a new hypothesis on dinosaur phylogeny. Traditionally, dinosaurs have been divided into the “bird-hipped” ornithischians and the “lizard-hipped” saurischians (this is extremely oversimplified, but it gets the basic idea across). However, the new study suggests that theropods, typically classified as saurischians, are actually more closely related to the ornithischians, in a grouping termed Ornithoscelida (first coined by Thomas Huxley in the 19th century, but widely abandoned and forgotten after that). This would mean that the group traditionally recognized as Saurischia would no longer exist, and would either need to be abandoned or redefined.
Of course, it should always be remembered that no study is the final word on any subject. This study will undoubtedly face some serious scrutiny by other dinosaur paleontologists. But that’s a good thing. Science is all about challenging ideas and putting them through rigorous testing. If the results described above don’t stand up to that testing, then we will probably go back to the old orthodoxy. But if the hypothesis withstands that barrage, it will mark a major paradigm shift in our understanding of dinosaur classification. However it turns out, I have little doubt that this will be the most controversial and talked about paper in dinosaur paleontology of the year, possibly even the decade. If you want to know more, I highly recommend Darren Naish’s write-up on TetZoo.