Israeli scholars find earliest proof of feather molt in flying dinosaur

One of the fossils clearly featured the marks of the feathers on the wings.

Fossil of Microraptor, a four winged dinosaur which lived 120 million years ago (photo credit: YOSEF KIAT - ANIMAL FLIGHT LABORATORY AT THE DEPARTMENT OF EVOLUTIONARY AND ENVIRONMENTAL BIOLOGY AN)
Fossil of Microraptor, a four winged dinosaur which lived 120 million years ago
(photo credit: YOSEF KIAT - ANIMAL FLIGHT LABORATORY AT THE DEPARTMENT OF EVOLUTIONARY AND ENVIRONMENTAL BIOLOGY AN)
A flying dinosaur called the Microraptor, which lived around 120 million years ago, was able to gradually replace its feathers like most modern birds, Israeli researchers have documented.
The findings of the study published on Thursday in the journal Current Biology documents the earliest evidence of sequential feather molt ever uncovered.
“It is fascinating to see how a mechanism that began to develop at least 120 million years ago also exists in today’s birds,” PhD candidate Yosef Kiat of the Animal Flight Laboratory in the Department of Evolutionary and Environmental Biology at the University of Haifa said in a press release. “It is also fascinating to see how we can use our modern knowledge about this mechanism in order to yield insights into the evolution and ecology of a dinosaur that lived 120 million years ago.”
Contrary to what happens with hair or claws, feathers cannot be renewed continuously from their base. They need to be shed completely before a new feather can grow.
Among modern birds, some species shed and completely replace their plumage in a concentrated period of time that can last several days or even weeks, while they are able to find cover from predators or from other dangers without flying. The process is called simultaneous molt. These species include many aquatic birds.
For other species, flying is essential for survival, and feather molt needs to occur gradually without preventing them from doing so, as was the case for the Microraptor, the researchers found.
Microraptors were small four-winged dinosaurs estimated to be no more than 80 centimeters long and to weigh less than a kilo.
The team examined a fossil found in the province of Liaoning, China, which clearly featured the marks of the feathers on the wings.
“Naturally, it’s by no means a routine matter to find a relatively complete dinosaur fossil, but it’s even rarer to find well-preserved fossilized wings,” Kiat said. “The feathers do not usually survive the fossilization process, but in this particular case most of the wing feathers can be seen very well.”
Some authors of the study personally visited China to examine the item and cooperated with Prof. Jingmai O’Connor and Prof. Min Wang from the Key Laboratory of Vertebrate Evolution and Human Origins and the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences.
“We are used to examining and studying molting in our regular bird-ringing work,” said Amir Balaban, a member of the research team from the Ariel Pavilion at the Jerusalem Observatory. “Coming face to face with a flying dinosaur that sunk into a primeval swamp millions of years ago is a very rare and exciting event.”
The team analyzed the six feathers visible on the fossil to understand if their different sizes were the result of sequential molt process or another cause. They were able to determine that the wing of the dinosaur possessed feathers of different lengths because they were getting replaced gradually.
The Microraptors’ ability to fly has been hotly debated among scholars. But the results of the investigation have allowed the authors of the paper to suggest that the small dinosaur actually spent a significant amount of its time in the air, likely to escape from predators and to procure food.
“We are waiting eagerly for the coronavirus to fade away so that we can return to the fossil storerooms across China and find additional milestones in the development of modern-day birds,” Balaban said.