Despite everything fossils can tell us about dinosaurs, a new study is changing some of the oldest research we have at our disposal. The study in question, published in the journal Nature today, not only changes how some dinosaurs are classified, but also suggests traits of a common ancestor and shakes up what we thought we knew about where dinosaurs came from.
That’s a lot to unpack, but then again, this is a pretty groundbreaking study if it can be backed up with further research. Perhaps most importantly, the study challenges the dinosaur “family tree” that was first put together by H.G. Seeley in 1888. Back then, Seeley classified dinosaurs by the structure of their pelvic bones.
This means that bipedal, meat-eating Theropoda like Tyrannosaurus and long-necked Sauropodomorpha like Apatosaurus were put into the same clade – Saurischia – while others like Triceratops were classified as Ornithischia. This study is challenging those classifications, with study author and University of Cambridge paleontologist Matthew Baron telling New Scientist that even though Seeley’s classifications were “brilliant for his time,” they are now “arguably archaic.”
Baron says that Seeley determined his classification by looking at “very few specimens,” and sought to rectify that with this new study. In it, he and his team looked at 74 species of dinosaurs, analyzing 457 different characteristics and discovering more differentiators that go beyond just the pelvic bone alone.
The result? A simple shift in the previously established family tree that has some major implications for the world of paleontology. Now, Theropoda are grouped with Ornithischia, forming the new clade Ornithoscelida, while Sauropodomorpha is joined in Saurischia by Herrerasauridae, a family of early carnivorous dinosaurs.
Assuming the evidence put forth in this study holds up, that discovery alone is enough to change modern-day paleontology. Baron and his team didn’t stop there, though, as this switch also suggests that a common ancestor to dinosaurs may have been omnivorous. It also suggests that dinosaurs may have evolved in the northern hemisphere of the Earth, rather than in South America as previously believed.
So, this is a pretty big discovery as far as our study of dinosaurs goes. There’s no doubt that there will plenty of debate about the results of this study moving forward, and it’ll be very interesting to see what the paleontology community at large has to say in the coming days and weeks.
More detailed information can be found in the paper “A new hypothesis of dinosaur relationships and early dinosaur evolution” as written by Matthew G. Baron, David B. Norman, and Paul M. Barrett. This paper can be found under code doi:10.1038/nature21700 in the scientific journal Nature.