Bird evolution may have been more complex and diverse than previously thought

New Jurassic fossils — including Baminornis from China and a well-preserved Archaeopteryx specimen — show varied early bird anatomy and raise questions about whether flight evolved once or multiple times.

New fossil discoveries are changing how scientists view the earliest birds. For decades Archaeopteryx was the only known bird genus from the Jurassic, about 150 million years old. Researchers described Baminornis from southeast China in February 2025 and, in May 2025, published analysis of a well-preserved Archaeopteryx specimen that had been in private collections. The new material shows unexpected anatomical differences among early birds and prompts fresh debate about the origins of flight. Key findings: - Archaeopteryx fossils date to about 150 million years ago and come from Germany; they combine pennaceous feathers with dinosaur-like traits such as teeth and claws on the wings. - Baminornis, described from the Zhenghe Fauna in February 2025, preserves a pygostyle (a fused tail bone) that is absent in Archaeopteryx and is typical of later birds. - The Chicago Archaeopteryx specimen, described in May 2025, exposes tertial feathers and a bird-like palate, traits linked to flight mechanics and feeding specialization. - Other fossils, including Microraptor and Yi, show different wing arrangements — four-winged limbs or membrane-bearing wrists — indicating varied aerial adaptations among theropods. - Researchers are divided about timing and number of origins of flight: some interpret the record as multiple independent experiments in aerial locomotion, while others favour a single origin with later diversification. Summary: The recent finds indicate that late-Jurassic bird-line animals were more anatomically varied than previously appreciated and that some bird-like traits appeared earlier than thought. These discoveries reopen questions about whether powered flight evolved once among theropods or multiple times independently. More fossil finds and clearer analyses of relationships are needed to resolve that question. Undetermined at this time.