You would think that any creature with four wings would be the master of the skies. But for one goose-sized dinosaur, despite having a feathered wing on each of its four limbs, was almost certainly grounded. The flightless dinosaur, which scurried about 160 million years, may help paleontologists explain how flight in birds evolved in the first place.
Discovered in northern China, the newly described dinosaur has been named Serikornis sungei, and could be key in understanding the origins of flight. Despite being covered in a downy plumage of feathers, and han impressive four wings, the bird is unlikely to have ever taken to the skies.
This is because a detailed analysis of its feathers, published in The Science of Nature, show that they lacked a crucial feature of modern feathers that allows them to stay stiff and resist the air. Known as "barbicels", these are the tiny hooks that form a cross-attachment between individual feathers, and Serikornis is notable in the fact that it is missing them. This, the researchers deduce, means that as the wind moved, it would have blown straight through the little dinosaur’s plumage.
But this is not the only reason that they suspect the theropod would have remained on solid ground. The feathers on the critter are very symmetrical, which when it comes to flight is actually a disadvantage. Not only that but the sternum on the animal, which in birds is where the muscles that power the wings are located, is also underdeveloped, while the bones in the wings are similarly not adapted for beating.
The irony is that despite Serikornis belonging to an early subgroup of dinosaurs that all had four wings, none of them were actually able to fly. Instead, it seems that the diminutive dinosaurs were likely scuttling around on the forest floor, darting between trees as they chased down their prey. But they may well have been starting to explore the arboreal environment, as they did possess a long claw that would have allowed them to grab onto tree bark and climb.
This then obviously raises the question of why the dinosaur was covered from head to toe in feathers in the first place. The researchers suspect that there could have been a few different pressures that enabled them to evolve their downy coat and multiple wings, such as sexual selection or perhaps as a warning to their enemies.
It was not until later in the Jurassic that barbicels finally evolved and allowed dinosaurs to start exploring the skies. It seems likely that they first began gliding from the trees that they were able to climb up, before starting to refine their aerobatic abilities with the beats of their wings.