This 127-Million-Year-Old Fossil Links Dinosaur and Bird Evolution

Yes, birds are technically modern dinosaurs. But sometimes it’s tough to tell where the non-avian dino ends and the bird begins. As John Pickrell at National Geographic reports, scientists have now discovered a 127-million-year-old fossil that blends its avian features with some pretty prehistoric quirks, shedding new light on the evolution of flying birds.

“[This is] one of the most important fossil birds found in recent years,” Steve Brusatte, a paleontologist at the University of Edinburgh who did not participate in the research, told Pickrell.

But despite occupying such a lofty branch on the tree of evolution, the newly-named Jinguofortis perplexus was kind of a hot mess. In fact, it derives the latter half of its name from its perplexing occupancy of a sort of dino-bird uncanny valley, according to new the paper published in the journal Proceedings of the National Academy of Sciences. As it turns out, J. perplexus may have been bafflingly ill-adapted at flying—due mostly to growing pains as it transitioned away from its dinosaur relatives.

For one, J. perplexus sported some features we don’t typically see on today’s chickens and crows, like a toothy jaw in place of a beak. But it was still, technically, a bird—more specifically, a short-tailed bird, or pygostyle. Studying this group as a whole has yielded a wealth of knowledge for paleontologists, since pygostyles seem to mark the transition from the “long, straight, skinny tails of [dinosaurs] into the little, fused, stubby tails [birds] have today,” Brusatte told Pickrell.

What’s more, J. perplexus had clawed wings, something Dennis Voeten, a paleontologist at Palacký University in the Czech Republic who was not involved in the study, told George Dvorsky at Gizmodo could evidence the switch from bulky hands to more flight-amenable digits. Modern birds have, essentially, “highly reduced” fingers in which the bones have fused to facilitate feathered flight, and J. perplexus seems to represent an intermediate stage in this serendipitous switch.

But perhaps the greatest hindrance to J. perplexus achieving liftoff was its fused shoulder girdle, or scapulocoracoid. Most modern birds have two bones that come together in a mobile joint in this spot, instead of one fused unit; this allows them the flexibility to beat their wings. J. perplexus’ fused girdle is “very unusual,” ornithologist Gerald Mayr of the Senckenberg Research Institute in Frankfurt, Germany, who was not involved in the study, told Pickrell; nowadays, this feature is typically a staple of only flightless birds like ostriches.

The researchers, led by Min Wang, a paleontologist at the Chinese Academy of Science in Beijing, believe that the fused shoulder girdle may have helped this ancient avian reach maturity faster. Still, because of the structure of its wings, Wang thinks J. perplexus was definitely flying—just maybe less efficiently, or differently, than most modern birds, Pickrell reports. But Mayr is cautious, and adds that J. perplexus’ aerodynamic abilities should be “confirmed in future studies.”

The fossil was discovered in what’s now the northeastern Chinese province of Hebei. During the early Cretaceous period, J. perplexus likely had its run (or flight) of the thickly forested region, using its 27-inch wingspan to navigate through the trees, where it snacked on plants, reports Dvorsky at Gizmodo.

In any case, one thing about J. perplexus’ movement mechanics seems clear: The bird’s wonky wings illustrate that the the evolution of avian flight “was not one direct path,” Voeten tells Dvorsky. “Dinosaurs may have ‘experimented’ with different flight styles and degrees of [flying] proficiency that went extinct together with the non-avian dinosaurs.”

Study author Wang agrees—and isn’t one to mince words. As he explains it to Pickrell at National Geographic, “This new bird fossil shows that [this evolutionary path] was much more messy [than we once thought].”

Katherine J. Wu | | READ MORE

Katherine J. Wu is a Boston-based science journalist and Story Collider senior producer whose work has appeared in National Geographic, Undark magazine, Popular Science and more. She holds a Ph.D. in Microbiology and Immunobiology from Harvard University, and was Smithsonian magazine's 2018 AAAS Mass Media Fellow.