China discovered the Jurassic flightless bird Yang Yuan𬸚𬸦, overturning the traditional understanding of the early evolution of birds

China News Service, Beijing, October 15 (Reporter Sun Zifa) The traditional understanding that "the origin and early evolution of birds has always been mainly adapted to flight" has been recently broken by new fossil discoveries in China and the research results of the Chinese scientific research team.

The fossil of a new species of bird from the late Jurassic period (approximately 148 million to 150 million years ago), Yang Yuanyan, was discovered in the Zhenghe Fauna of Fujian Province. It confirms that birds have been ecologically specialized as ground-dwelling and incapable of flight at the beginning of their evolution. They are the earliest known birds without the ability to fly and show a combination of dinosaur-bird morphological characteristics.

This disruptive breakthrough in the study of bird evolution was jointly completed by Wang Min's team at the Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, and collaborators from the Fujian Academy of Geological Sciences. The relevant paper was published online in the international academic journal "Nature" on the night of the 14th, Beijing time.

Yang Yuan’s holotype specimen and skeleton reconstruction. (Photo provided by Wang Min)

Researcher Wang Min, the corresponding author and co-first author of the paper, said that in this study, a new Jurassic bird fossil was discovered near the core fossil site of the Zhenghe fauna, named Yangyuan𬸚𬸦. It has also become another important discovery of the Jurassic Zhenghe fauna by the research team after the strange Fujianosaurus, Zhenghe Baminornithes, and Fuyu Zhengheornis.

According to the research team, Yang Yuan's skull weighs about 821 grams and shows that the skull has the typical characteristics of troodontids, and its shape is similar to that of primitive birds. It is characterized by a high degree of mosaic evolution.

Comprehensive analysis results prove that Yangyuan𬸚𬸦 belongs to a bird rather than a deinonychus. It is a sister group to Zhenghebaminornis, forming a new early bird taxon Zhengheornithidae. 𬸚𬸦It is more primitive than the Bamin bird of the same era and is one of the most primitive birds known.

The study of ecological habits also shows that the Yang Yuan 𬸚𬸦 is a carnivorous bird that does not have the ability to fly but is adapted to a life of running on land.

The research team said that Yang Yuan's discovery has filled a key space-time evolution gap in the evolution of birds. As the earliest known bird without the ability to fly, the emergence of 𬸚𬸦 breaks the one-way evolution hypothesis of flight and proves that the evolution of bird body structure does not advance linearly along a single path of "optimized flight", but is a complex process accompanied by rapid ecological niche exploration.

So far, the Zhenghe fauna has discovered the strange Fujianosaurus, which is adapted to running, the Zhenghe Baminbird with a tail bone, the Fuyu Zhenghebird with a shortened tail and a petite body. The latest research has also discovered the Yangyuan 𬸚𬸦, which has shortened forelimbs and is adapted to ground dwelling. "This shows that rich ecological diversity has exploded at the origin of birds. The Zhenghe fauna is like an ultra-high-resolution space-time camera, recording these key evolutionary moments," Wang Min said. (over)