China discovers Jurassic flightless bird fossil, challenging traditional views on avian evolution

(ECNS) — A newly discovered fossil of a Jurassic bird in China has challenged the long-held view that flight was the primary driving force behind the origin and early evolution of birds, researchers said.

The fossil, discovered in the Zhenghe Fauna in east China's Fujian Province, belongs to a new species named Yuezhuornis yangyuanensis. Dating to between 148 million and 150 million years ago, the bird is the earliest known flightless bird and combines dinosaur-like and bird-like features.

The research was conducted by a team led by Wang Min of the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences, in collaboration with the Fujian Institute of Geological Survey. The findings were published in the journal Nature on Wednesday.

A new discovery in the Zhenghe Fauna

The transition from land-dwelling dinosaurs to flying birds is one of the most remarkable events in the history of life, involving changes in the skeletal, muscular and nervous systems, skin-derived structures and behavior, said Wang, the study's corresponding author and a co-first author.

Macroevolutionary models suggest that birds originated and began diversifying during the Jurassic Period. However, the scarcity of bird fossils from this critical period has left scientists with limited direct evidence of how the characteristic bird body plan emerged.

Researchers have long believed that selective pressure associated with flight was the primary driver of early bird evolution. The independent emergence of many flight-related features in birds and their dinosaur relatives appeared to support this view. A lack of fossils from key evolutionary stages, however, has limited scientists' understanding of the early evolutionary pathways and ecological diversity of birds.

The fossil was found near a major fossil site in the Zhenghe Fauna. The species name yangyuanensis comes from Yangyuan township, where the fauna was discovered, while the genus name Yuezhuornis is derived from a mythical Chinese bird mentioned in the ancient text Discourses of the States.

The discovery adds to earlier fossil finds from the Jurassic Zhenghe Fauna, including Fujianvenator prodigiosus, Baminornis zhenghensis and Eopengornis species.

(By Helen Mo)