The recent analysis of hundreds of preserved bird specimens from museum collections worldwide has shed light on the specific set of feather rules that are crucial for the power of flight. Paleontologists have discovered that these rules are not only key to understanding the flight of birds but also to predicting which dinosaurs may have been capable of flight. According to Field Museum of Natural History paleontologist Jingmai O’Connor, the success of theropod dinosaurs, including birds, can be attributed to their flight abilities and the unique structures of their feathers.
One of the most fascinating discoveries from the analysis is the consistent presence of 9 to 11 asymmetrical flight feathers, known as primaries, in all flying birds. From the smallest hummingbird to the largest eagle, this specific number of primary feathers is a common trait. In contrast, flightless birds exhibit a wide range of variations in the number of primary feathers, with emus completely lacking them and penguins boasting up to 40. This finding highlights a crucial link between the number of primaries, feather symmetry, and wing proportions with the flight capacity of modern birds.
By examining fossils dating back up to 160 million years, researchers have been able to identify which bird ancestors possessed the necessary feather traits for flight. Among the extinct species analyzed, some showed clear indications of flight capabilities based on their feather structure, while others did not. For instance, Archeopteryx and Microraptors were identified as likely flyers, despite being distinct from modern birds. On the other hand, Caudipteryx, although having the correct number of primary feathers, exhibited almost symmetrical feathers, suggesting a loss of flight ability in its lineage.
Single Evolutionary Event
The analysis conducted by Kiat and O’Connor challenges previous claims that flight evolved multiple times in dinosaurs. They argue that the anatomical requirements for flight evolved in a common ancestor of various dinosaur groups before they branched out. While some species like Caudipteryx became flightless early on, others like Microraptors retained their flight abilities but ultimately faced extinction. The study emphasizes the importance of examining feather structure in assessing the flight potential of dinosaurs, rather than relying solely on skeletal data.
Uncovering Early Wing Evolution
Despite the significant insights gained from the analysis, researchers acknowledge that there are still gaps in our understanding of the early stages of wing evolution. The fossil record may not provide a complete picture of how flight evolved in dinosaurs, leaving room for further research and discoveries. Kiat and O’Connor’s study serves as a stepping stone in unraveling the mysteries of flight evolution and the diverse pathways taken by ancient flying creatures.