With the help of UV light and CT scans, scientists have uncovered extraordinary details in the most complete Archaeopteryx fossil ever studied — revealing how this feathered dinosaur may have taken to the skies.
Key Points at a Glance
- The Chicago Archaeopteryx preserves more fine detail than any previously known specimen.
- Advanced imaging uncovered soft tissues and a crucial set of flight-enabling feathers.
- Discovery of long tertial feathers suggests Archaeopteryx was capable of powered flight.
- This fossil offers new clues about bird evolution, cranial mobility, and feather function.
- The findings revive debate on how often flight evolved among feathered dinosaurs.
More than 160 years after its discovery, Archaeopteryx — the ancient, feathered dinosaur that helped confirm Darwin’s theories — is once again reshaping science. In a new study published in Nature, scientists from the Field Museum have revealed astonishing new features of the most pristine Archaeopteryx fossil ever examined. The so-called “Chicago Archaeopteryx,” which debuted at the museum in 2024, offers a remarkably complete look at this early flyer — from the scales on its toes to a set of never-before-seen flight feathers that may explain why it could soar while other feathered dinosaurs stayed grounded.
Archaeopteryx lived roughly 150 million years ago during the Jurassic Period and has long held a pivotal role in evolutionary biology. It represents the transition between non-avian dinosaurs and modern birds. The new fossil — the smallest Archaeopteryx ever found, about the size of a pigeon — was unearthed decades ago in the Solnhofen limestone of Germany but remained in private hands until the Field Museum acquired it in 2022.
“When we first got our Archaeopteryx, I was like, this is very, very, very cool,” said Jingmai O’Connor, lead author and associate curator of fossil reptiles at the Field Museum. “But I wasn’t sure what new things we would be able to learn.” As it turns out, quite a lot.
Thanks to meticulous preparation by the museum’s fossil team, led by Akiko Shinya, and aided by high-resolution CT scans and ultraviolet light, the team unearthed exquisite new anatomical features, including soft tissues, fine-scale bones, and an overlooked set of feathers that may have been critical for flight. The result: the most detailed view of any Archaeopteryx fossil to date.
CT scanning was essential in guiding the fossil’s preparation. “It let us know things like, the bone is exactly 3.2 millimeters below the surface of the rock,” O’Connor said. UV light, meanwhile, revealed preserved soft tissues that fluoresce due to the unique chemistry of the Solnhofen deposits — from toe scales to delicate wing feathers invisible to the naked eye.
But the star of the study is a set of tertial feathers attached to the bird’s long upper arm bone — feathers never before documented in any Archaeopteryx. These feathers would have filled a critical aerodynamic gap between the body and wing, a feature seen in modern birds that helps maintain lift during flight. Their presence in this fossil suggests that Archaeopteryx wasn’t just a feathery relic — it was a true flyer.
“Compared to most living birds, Archaeopteryx has a very long upper arm bone,” O’Connor explained. “That could disrupt flight if there’s a gap between the feathers and the body. These newly observed tertials would have filled that gap and made flight possible.”
Notably, such feathers are absent in close dinosaur relatives of birds, implying that this feature — and perhaps flight itself — evolved multiple times in the dinosaur lineage. “This tells us that non-avian feathered dinosaurs couldn’t fly, but Archaeopteryx could,” said O’Connor. “That suggests dinosaurs evolved flight more than once, which I think is super exciting.”
Beyond flight, the fossil has offered new insights into bird skull evolution. Bones in the roof of the mouth hint at the origins of cranial kinesis — the ability of birds to move their upper beaks independently from their skulls — which may have helped them adapt to different ecological niches, contributing to the incredible diversity of birds today.
The fossil’s limbs also reveal soft tissues that support the idea that Archaeopteryx spent time walking and possibly climbing, adding nuance to its lifestyle and behavior.
This study, contributed to by a multinational team of paleontologists, is only the beginning. “We’re learning something exciting and new from just about every part of the body that we have preserved,” said O’Connor. “And this paper is really just the tip of the iceberg.”
More revelations may be on the way — all from a small, glowing fossil that continues to bridge the ancient and modern skies.
Source: Field Museum
