“This finding has broad significance, as it recommends that the advancement of flight throughout the development of dinosaurs and birds was even more intricate than formerly thought,” stated Tel Aviv University paleontologist Yosef Kiat and his coworkers.

“In truth, specific types might have established fundamental flight capabilities– and after that lost them later on in their development.”

“The dinosaur family tree split from other reptiles 240 million years back.”

“Soon later on (on an evolutionary timescale) lots of dinosaurs established plumes– a special light-weight and strong natural structure, made from protein and utilized primarily for flight and for protecting body temperature level.”

Around 175 million years earlier, a family tree of feathered dinosaurs called Pennaraptora emerged– the remote forefathers of modern-day birds and the only family tree of dinosaurs to endure the mass termination that marked completion of the Mesozoic period 66 million years earlier.

As far as we understand, the Pennaraptora group established plumes for flight, however it is possible that when ecological conditions altered, a few of these dinosaurs lost their flight capability– much like the ostriches and penguins these days.

In the research study, the authors analyzed 9 specimens of a feathered pennaraptoran dinosaur types called Anchiornis huxleyi

An uncommon paleontological finding, these fossils– and numerous hundred comparable ones– were maintained with their plumes undamaged, thanks to the unique conditions dominating in the area throughout fossilization.

Particularly, the 9 fossils analyzed in the research study were picked since they had actually kept the color of the wing plumes– white with a black area at the idea.

“Feathers grow for 2 to 3 weeks,” Dr. Kiat stated.

“Reaching their last size, they remove from the capillary that fed them throughout development and end up being dead product.”

“Worn with time, they are shed and changed by brand-new plumes– in a procedure called molting, which informs a crucial story: birds that depend upon flight, and hence on the plumes allowing them to fly, molt in an organized, steady procedure that keeps proportion in between the wings and permits them to keep flying throughout molting.”

“In birds without flight capability, on the other hand, molting is more random and irregular.”

“Consequently, the molting pattern informs us whether a specific winged animal can flight.”

The maintained plume pigmentation in the dinosaur fossils from China enabled the scientists to determine the wing structure, with the edge including a consistent line of black areas.

They were able to differentiate brand-new plumes that had actually not yet finished their development, given that their black areas deviated from the black line.

A comprehensive examination of the brand-new plumes in the 9 fossils exposed that molting had actually not taken place in an organized procedure.

“Based on my familiarity with modern-day birds, I recognized a molting pattern showing that these dinosaurs were most likely flightless,” Dr. Kiat stated.

“This is an unusual and specifically interesting finding: the maintained pigmentation of the plumes provided us a special chance to determine a practical quality of these ancient animals– not just the body structure maintained in fossils of skeletons and bones.”

“Feather molting appears like a little technical information– however when analyzed in fossils, it can alter whatever we considered the origins of flight,” he included.

Anchiornis huxleyi now signs up with the list of dinosaurs that were covered in plumes however not efficient in flight, highlighting how complicated and varied wing development genuinely was.”

The findings were released in the journal Communications Biology

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Y. Kiat et al2025. Wing morphology of Anchiornis huxleyi and the development of molt techniques in paravian dinosaurs. Commun Biol 8, 1633; doi: 10.1038/ s42003-025-09019-2