Dinosaur fossils preserved with feathers suggest that some of these animals had already lost the ability to fly. “Feather molt seems like a small technical detail, but when studied in fossils it has the potential to change everything we thought about the origins of flight, highlighting just how complex and diverse the evolution of feathers really was,” the researchers said.
A new study led by researchers from Tel Aviv University’s Department of Zoology and the Steinhardt Museum of Natural History analyzed rare fossils with intact feathers and found evidence that these dinosaurs did not have the ability to fly. This rare discovery provides an unusual perspective on how animals lived 160 million years ago and sheds new light on how flight evolved in both dinosaurs and modern birds. The researchers said: “This discovery has far-reaching significance because it suggests that the development of the ability to fly during the evolution of dinosaurs and birds was much more complex than previously thought. In fact, certain species may have developed basic flight abilities but lost them later in evolution.”
The study was led by Dr. Yosef Kiat with collaborators from China and the United States and was published in the journal Science. communication biology By Nature Portfolio.
How did dinosaur feathers evolve?
Dr. Chiat, an ornithologist who studies feathers, explains that dinosaurs diverged from other reptiles about 240 million years ago. Shortly thereafter (on an evolutionary time scale) many species developed feathers. Feathers are lightweight protein-based structures used for flight and temperature regulation. About 175 million years ago, a group of feathered dinosaurs known as Pennaraputra appeared. These animals are considered distant ancestors of modern birds and were the only dinosaur lineage to survive the mass extinction at the end of the Mesozoic era 66 million years ago.
Scientists believe Penaraputra evolved feathers for flight, but environmental changes may have caused some species to lose that ability over time, similar to today’s flightless birds such as ostriches and penguins.
A rare fossil that preserves the color and structure of feathers
The study focused on nine fossils from eastern China belonging to the feathered pennaraptorian dinosaur Anchiornis. These fossils are extremely rare because, thanks to the unique fossilization conditions of this region, not only the feathers but also the original color have been preserved. Each specimen had white wing feathers with distinct black spots on the tips.
This preserved color allowed researchers to closely examine the structure and growth of the feathers in a way not normally possible with fossils.
Molting pattern reveals flight ability
Dr. Kiat explains that the feathers grow over a period of two to three weeks, after which they become detached from the blood supply and become non-living. Over time, they wear out and are replaced in a process known as shedding. This process reveals whether an animal can fly or not.
“Two to three feathers. They grow in weeks. Once they reach their final size, they become detached from the blood vessels that nourished them during growth. Over time, the feathers fall off and are replaced by new feathers. This tells an important story. , they molt in an orderly, step-by-step process that maintains the symmetry between the feathers and allows them to continue flying while their wings regrow.In contrast, non-flying birds’ molting is more random and irregular, so the molting pattern can tell us whether a winged creature was capable of flight.
By examining the fossilized feathers, researchers found a series of black spots along the edges of the wings. They also found developing wings with misaligned black spots, indicating that the wings were still growing. Detailed analysis revealed that the molting pattern was irregular rather than regular.
Evidence that Anchiornis could not fly
Dr. Kiat concluded: “Based on my knowledge of modern birds, I have identified a molting pattern that indicates that these dinosaurs were probably flightless. This is a rare and particularly interesting finding. The preserved feather coloration has given us a unique opportunity to identify the functional characteristics of these ancient creatures, as well as the body structure preserved in their skeletons and bone fossils.”
He added: “Feather molting seems like a small technical detail, but when studied in fossils it could change everything we’ve ever thought about the origins of flight. Anchiornis joins the list of feathered but non-flying dinosaurs, highlighting just how complex and diverse the evolution of wings really was.”
