The Dinosaur with Four Wings but Can't Fly

Fagjun | Published 2017-09-07 07:41


In this irony of ironies, a dinosaur with four wings but can't fly might be able to teach scientists about how flight evolved in birds.


Artist's impression of Serikornis sungei by Emily Willoughby



What does a four-winged dinosaur look like anyway? This one—the newly-named Serikornis sungei—is another species in a list of four-winged dinosaurs. It's about the size of a goose or a pheasant, about a foot and a half long, covered with wispy, downy feathers. Its forelimbs and hindlimbs were so heavily feathered that they were effectively wings. The word “effectively” may be quite a stretch, though, as evidence suggests that Serikornis can't actually fly.


The fossil was found in 2014 in Liaoning Province in China, a province well-known for its preserved bird and dinosaur remains. Other four-winged dinosaurs such as the Microraptor, Aurornis, and Anchiornis were also found in Liaoning. As scientists made more and more discoveries of four-winged dinosaurs, they began to gain more insight into how flight evolved—in other winged animals, that is.



What are Wings For?


The Serikornis fossil [Photo by Ulysse Lefèvre]



Wings are useless if the plumage itself isn't right. The feathers on Serikornis are completely missing microstructures called barbules, which makes feathers stiff and resistant to air pressure. The absence of barbules means that Serikornis can't use its wings to fly. Without barbules, air would have just pushed past between the feathers.


Thus, what are the feathers for if not for aiding flight? Paleontologist Ulysse Lefèvre, lead researcher for the study on the dinosaur with four wings, says that the feathers may have functioned as insulation. It's also possible that the feathers were used to repel rivals or attract potential mates.



A close-up on the fossil's wing [Photo by Thierry Hubin, RBINS]



Serikornis may not have been able to fly, but it can help scientists figure out how other animals, like birds, began to take off for the skies. One feature to look at is the long plumage on the dinosaur's limbs and feet. This kind of long feathers can also be seen on early birds and feathered dinosaurs. If the animal were able to fly, these long feathers would help steer. However, if that were their function, then they wouldn't be necessary to a dinosaur that can't actually fly.


It's definitely a thinker. Maybe, some scientists contend, Serikornis actually was able to fly.



The Dinosaur with Four Wings and the Origin of Flight


A comparison between Serikornis and Anchiornis [Image by Lefèvre et al.]



According to Mike Benton, a paleontologist at the University of Bristol, Serikornis's hindwings are actually an inconvenient feature to have for a ground-dwelling dinosaur. That is, of course, if Serikornis really was unable to fly. Benton thinks that the dinosaur's four wings presented a precursor to actual flight, and that the dinosaur was able to climb trees and glide from bough to bough.


Lefèvre doesn't disagree. He also thinks that it's possible that Serikornis was able to glide from tree branch to tree branch to escape predators or generally move around. Still, gliding isn't flying. Lefèvre thinks that Serikornis's wings might have slowed down the dinosaur's descent, but they didn't propel it to the sky.


It wasn't until the late Jurassic that barbicels began to evolve, giving feathered and winged dinosaurs the chance to fly. The flightless dinosaur with four wings may have paved the way for later species to finally be able to explore the skies.


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