The dinosaur family tree may need to be radically rewritten — and even uprooted and replanted elsewhere, a new analysis of about 75 different species shows.The findings, published in the journal Nature, hint that dinosaurs might have originated in the northern hemisphere rather than the southern, and could upend an understanding of dinosaur evolution that has gone largely unchallenged for some 130 years.“We might all have to rearrange our mental furniture,” Kevin Padian, a University of California, Berkeley professor of integrative biology who was not involved in the study, wrote in a commentary.If other scientists test the authors’ hypothesis and also find that the family tree is in for major pruning and grafting, the findings could have major implications for our understanding of dinosaur evolution.“We know this will be controversial,” said lead author Matthew Baron, a paleontology doctorate student at the University of Cambridge. “We are disagreeing with 130 years of consensus. “Some people have expressed a desire to test our hypothesis for themselves, and we really do welcome that. We want this to start a great new debate in our field, and we hope that people test our ideas and search for new specimens and new evidence that might support or refute our finds.”To figure out the family tree of long-extinct animals with fossilized bones, scientists have to carefully study their shared features to see which ancient species were related, and what their common ancestors looked like. It’s tricky and painstaking work, especially since similar physical features can sometimes emerge independently in two different species.Historically, dinosaurs have largely been categorized according to the shape of their pelvic bones:Grouped either into “bird-hipped” dinosaurs such as Ornithischia, a group that includes stegosaurus, triceratops and duck-billed hadrosaurs, Or into the “reptile-hi ...
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