Researchers likely overestimated number of species: expert
About one-third of all dinosaur species may never have existed, says paleontologist Jack Horner of the Museum of the Rockies in Montana, after researchers there determined that two species of dome-headed dinosaurs are actualy just immature versions of a different kind, the Pachycephalosaurus. This comes after last month’s revelation that a three-horned dinosaur, the Torosaurus, was actually an old Triceratops, not a separate species. What’s more, over the last few years, several duck-billed hadrosaurs and the Nanotyrannus, thought to be a smaller Tyrannosaurus rex, were found to be previously named species. According to Horner, the confusion comes from the shields, spikes and horns on dinos’ heads; research is showing they changed as the dinosaur aged. “Juveniles and adults of these dinosaurs look very, very different from adults, and literally may resemble a different species. But some scientists are confusing morphological differences at different growth stages with characteristics that are taxonomically important. The result is an inflated number of dinosaurs in the late Cretaceous,” Mark B. Goodwin, co-author of the research, told the Telegraph. “Dinosaurs are not mammals, and they don’t grow like mammals.”