FUZHOU, Feb. 13 (Xinhua) -- Researchers in China have announced the discovery of the oldest known short-tailed bird fossil, which dates back approximately 150 million years, in Zhenghe County, Fujian Province.

The find, Baminornis zhenghensis, suggests that the origins of modern birds may precede previous scientific estimates.

The fossil exhibits a pygostyle, a fusion of bones found in contemporary birds that provide structural support for their tails.

The presence of this characteristic indicates that aspects of modern bird anatomy were already emerging during the Late Jurassic Period, specifically 20 million years earlier than previously thought.

Baminornis zhenghensis reveals a unique mix of anatomical features, including shoulder and pelvic girdles resembling those of modern birds, alongside a hand structure reminiscent of non-avian dinosaurs.

According to Wang Min, a leading researcher with the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) under the Chinese Academy of Sciences (CAS), this juxtaposition of traits presents an intriguing contradiction.

Academician Zhou Zhonghe of the CAS emphasized the significance of this find, stating that it challenges the long-held view that Archaeopteryx was the only bird known from the Jurassic Period.

The researchers postulate that the emergence of early birds could date back to as early as 172 to 164 million years ago.

This study was conducted collaboratively between researchers from IVPP and the Fujian Institute of Geological Survey and is published in the latest edition of the journal Nature.

The evolutionary transition from dinosaurs to birds has been a topic of considerable debate among scientists, with varying opinions on the timeline and the nuances of this process.

While it is well established that birds evolved from theropod dinosaurs, the fossil record has been sparse, complicating the understanding of when diversification occurred.

Archaeopteryx, traditionally considered the earliest bird, possesses feathers but also features characteristic of non-avian dinosaurs, such as a long tail.

Wang indicated that if doubts exist regarding the classification of Archaeopteryx as a bird, then Baminornis zhenghensis stands out as the most definitive avian fossil from the Jurassic.

The transition involved significant changes in tail anatomy, specifically the shortening of the tailbone, which plays a critical role in flight mechanics.

Estimates suggest that Baminornis zhenghensis weighed around 100 grams and may have inhabited a swampy habitat.

Wang noted that evidence indicates its flight capabilities could surpass those of Archaeopteryx, although the incomplete nature of the fossil limits definitive conclusions about its flying posture.

Further analysis of the fossil allowed researchers to position Baminornis zhenghensis within the avian evolutionary tree, suggesting it diverged from the lineage just after Archaeopteryx.

Additionally, at the same excavation site, researchers uncovered a second fossil consisting solely of a furcula, or wishbone, which was identified as belonging to the Ornithuromorpha group, prevalent during the Cretaceous Period.

Wang stated that these findings confirm the existence of at least two species of birds in the Zhenghe Fauna.

The implications of these discoveries suggest an earlier timeline for avian evolution, indicating that birds likely began to diversify during the Jurassic Period.

Zhou remarked that these fossils constitute significant evidence pointing to a rich evolutionary history of birds.

Paleontologist Stephen L. Brusatte from the University of Edinburgh categorized Baminornis as a landmark discovery, ranking it alongside the foundational discoveries of Archaeopteryx in terms of importance.

Xu Xing, another CAS academician and head of IVPP, expressed hopes for future discoveries that may further illuminate our understanding of the anatomical and behavioral transitions that led to the vast diversity of bird species present today.