Research Highlight - New Fossil Reveals Surprising Details about Archaeopteryx, the Iconic Early Bird

A groundbreaking study published in Nature has unveiled the most complete and well-preserved specimen of Archaeopteryx ever discovered, shedding new light on the evolution of early birds. The 14th known specimen, dubbed the "Chicago specimen," provides unprecedented insights into the skeletal structure, plumage, and ecology of this iconic creature, bridging the gap between dinosaurs and modern birds.

    Discovered in a talus pile in Germany and now housed at the Field Museum of Natural History, the fossil is nearly complete and uncrushed, preserved in three dimensions. Using micro-computed tomography (μCT) scans, researchers reconstructed the specimen’s anatomy in remarkable detail. The findings challenge previous assumptions about Archaeopteryx’s skull, flight adaptations, and lifestyle.

One of the most surprising revelations involves the skull’s palatal structure, which shows a mix of traits from troodontid dinosaurs and later birds. This suggests a closer evolutionary link between birds and troodontids than previously thought. The skull also exhibits reduced rigidity, an early step toward the cranial kinesis seen in modern birds.

Fig: Skull of Archaeopteryx FMNH PA 830 and palatal reconstructions of select paravian theropods with a cladogram depicting their relationships.

The fossil’s soft tissue preservation offered further surprises. Skin traces on the hand indicate that Archaeopteryx’s minor digit was free and mobile, contradicting earlier theories that it was bound to the major digit. Foot pads adapted for walking suggest Archaeopteryx spent significant time on the ground, though it likely also perched in trees—similar to modern pigeons.

Perhaps the most striking discovery is the presence of specialized wing feathers called tertials, which helped streamline the wing for flight. These feathers, absent in non-avian dinosaurs, suggest Archaeopteryx was more advanced in its flight capabilities than previously believed. The tertials may also have served roles in display or protection, hinting at complex behaviors.

"This specimen is a game-changer," said lead author Jingmai O’Connor. "It clarifies the mosaic of traits in Archaeopteryx and refines our understanding of how flight evolved."

The study underscores Archaeopteryx’s pivotal role in unraveling the dinosaur-bird transition, offering fresh clues about the origins of avian flight and ecology. With its wealth of new data, the Chicago specimen cements Archaeopteryx’s status as a keystone in evolutionary science.

For more details, the full study is available in Nature, and the 3D models are accessible via MorphoSource.

Reference

O’Connor, J., Clark, A., Kuo, PC. et al. Chicago Archaeopteryx informs on the early evolution of the avian bauplan. Nature (2025). https://doi.org/10.1038/s41586-025-08912-4