Jurassic bird fossil points to early flightless lifestyle

Researchers have described Yuezhuornis yangyuanensis, a small Jurassic bird whose anatomy suggests it lived on the ground and lacked powered flight, adding evidence of diverse lifestyles near the origins of birds. The study was published in Nature on October 14, 2026. The fossil, found in 2024 in the Zhenghe Fauna of southeastern China, dates to roughly 148 million to 150 million years ago. Researchers estimate the animal weighed about 0.8 kilograms, or 1.8 pounds, and was approximately crow-sized. Its short forelimbs relative to its hindlimbs distinguish it from many early birds associated with flight. A comparison of its limb proportions with 377 living bird species found the closest matches among terrestrial birds. The researchers interpret the proportions as evidence that Yuezhuornis was adapted for life on land and lacked powered flight. Those conclusions are drawn from anatomy and comparison, rather than direct evidence of how the animal moved. Its skeleton combines bird-like and dinosaur-like traits. The fossil has bird-like features including a pelvis, alongside serrated teeth and a prominent, sickle-shaped claw on the second toe, traits associated with predatory...