A study published in Nature on Wednesday describes the most well-preserved Archaeopteryx specimen to date. The specimen, acquired by the Field Museum of Natural History in Chicago in 2022, provided scientists with information about the ancient creature's flight capabilities and its pivotal role in the evolutionary transition from dinosaurs to birds.
Dr. Jingmai O'Connor, the Field Museum's associate curator of fossil reptiles and lead author of the study, expressed her excitement about the discovery. "When we first got our Archaeopteryx, I was like, this is very, very, very cool, and I was beyond excited," she said, according to Popular Science. Despite her enthusiasm, O'Connor admitted initial doubts about what new information could be gleaned from a species that has been studied for over a century. "Archaeopteryx has been known for so long, I wasn't sure what new things we would be able to learn," she explained.
The Archaeopteryx specimen, often referred to as the Chicago Archaeopteryx, is considered the best-preserved example of the species. Its exceptional state allowed researchers to examine both the skeleton and soft tissues in detail. By employing advanced imaging techniques, including CT scans and ultraviolet lighting, the team revealed new features of the creature's plumage, skull, and ecological adaptations.
One of the discoveries was the presence of tertial feathers on the upper arms of Archaeopteryx. These feathers were crucial for flight, filling the gap between the primary and secondary feathers and the body to create a continuous wing surface necessary for generating lift. "This is actually my favorite part of the paper," O'Connor said. "[It] provides evidence that Archaeopteryx was using its feathered wings for flying." The presence of tertial feathers placed Archaeopteryx more accurately on the evolutionary tree among winged dinosaurs and as a predecessor to modern birds.
The study also shed light on the creature's lifestyle and ecological adaptations. The feet of the Chicago Archaeopteryx resembled those of contemporary ground-foraging birds, suggesting it spent time on the ground. However, certain features indicate it may have also been capable of perching on branches. "The feet are similar to those of living birds that spend time on the ground," O'Connor noted, supporting the hypothesis that Archaeopteryx led a versatile lifestyle.
Further examination of the skull revealed important evolutionary developments. The researchers were able to study the palatal region, or roof of the mouth, which is rarely preserved in fossils. This provided insights into the transition from the rigid, immobile skulls of non-avian dinosaurs to the more lightweight and flexible skulls of birds. "That might not sound exciting, but to people who study bird evolution, it's really important," O'Connor said. "It's been hypothesized that being able to evolve specialized skulls for different ecological niches might have helped birds evolve into more than 11,000 species today."
Archaeopteryx, which lived about 150 million years ago during the Jurassic Period, is widely accepted as one of the earliest known birds. The new findings support the idea that it could indeed fly by flapping its wings, making it the earliest known dinosaur capable of powered flight using its feathers. "Archaeopteryx is not the first dinosaur with feathers, nor is it the first dinosaur with wings," O'Connor stated. "However, we think it is the earliest known dinosaur that could use its feathers for flying."
The meticulous preparation of the fossil, which took over 1,300 hours, was aided by the use of CT scanning and ultraviolet imaging. These techniques allowed the scientists to differentiate between the fossilized remains and the surrounding rock without damaging the delicate bones and soft tissues. "CT scanning was very important for our preparation process," O'Connor explained. "It let us know things like, the bone is exactly 3.2 millimeters below the surface of the rock, which let us know exactly how far we could go before we would hit the bone."
The article was written with the assistance of a news analysis system.