Bird evolution timeline pushed back at least 20 million years by new discovery

Bird evolution has taken a remarkable turn with the discovery of two ancient fossils from a species named Baminornis zhenghensis, which lived in what is now southeast China’s Fujian Province.

Dated to approximately 149 million years ago, these Jurassic-era fossils provide crucial insights into the early diversification of birds.

The fossils were unearthed by a team of scientists from the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) of the Chinese Academy of Sciences, which is a leading institution in paleontological research.

Spearheading the study was Professor Wang Min, whose work continues to reshape our understanding of avian ancestry.

Bird evolution theory – the basics

The current leading theory on bird evolution says that modern birds evolved from small, feathered theropod dinosaurs – yep, the same group that includes T. rex.

Scientists believe that around 150 million years ago, some of these dinosaurs developed feathers not just for warmth but also for gliding and eventually powered flight.

The famous Archaeopteryx, often called the “first bird,” had both dinosaur-like traits (teeth, claws, and a long bony tail) and bird-like features (feathers and wings).

Over millions of years, these early birds became lighter, developed better flying skills, and adapted to different environments, eventually giving rise to the diverse bird species we see today.

From the shadows of Archaeopteryx

Archaeopteryx, despite its feathered wings, bears close resemblance to non-avialan dinosaurs.

Notably, this is due to its distinctively long reptilian tail – a vivid departure from the short-tailed morphology observed in modern and Cretaceous birds.

Reflecting on the classification of Archaeopteryx, recent studies have placed it as a deinonychosaurian dinosaur, a sister group to birds.

This brings up an intriguing question: Do we have any definitive records of Jurassic birds?

Meet Baminornis zhenghensis

This is where the new discovery steps in. Among the two fossils found in Fujian Province, the team named one Baminornis zhenghensis.

This fossil exhibits an exclusive set of features: the shoulder and pelvic girdles resemble ornithothoracine birds, and there is an early-stage hand structure similar to that found in non-avialan dinosaurs.

Perhaps a standout feature of Baminornis zhenghensis is its short tail that ends in a compound bone called the pygostyle, a feature that is also prominent in contemporary birds.

“Previously, the oldest record of short-tailed birds is from the Early Cretaceous. Baminornis zhenghensis is the sole Jurassic and the oldest short-tailed bird yet discovered, pushing back the appearance of this derived bird feature by nearly 20 million years,” Prof. Wang stated.

Bridging a large gap in bird evolution

What makes this discovery so intriguing?

These fossils present compelling evidence that birds began diversifying much earlier than previously thought.

Typically, Earth’s most diverse group of terrestrial vertebrates – birds, are believed to have diversified during the Jurassic period.

But the details of this diversification were shrouded in mystery due to a significant shortage of tangible fossil records.

Until now, the only widely accepted Jurassic bird was Archaeopteryx.

Baminornis zhenghensis: An early bird

To fully understand the positioning of Baminornis zhenghensis in the bird evolution tree, the research team utilized several investigative methods.

The results indicated that this bird had evolved from Archaeopteryx, making it one of the oldest birds ever found.

“If we take a step back, and reconsider the phylogenetic uncertainty of Archaeopteryx, we do not doubt that Baminornis zhenghensis is the true Jurassic bird,” Dr. Zhou Zhonghe, a co-author of the study, stated confidently

The second fossil is far from complete and consists solely of a furcula (a bone in the chest of birds).

Despite its poor preservation, the team remains hopeful that it might help in establishing the evolutionary link between non-avialan and avialan theropods.

What happens next?

The researchers revealed that the results of the analyses support that this furcula belonged to a member of the Ornithuromorpha, a diverse set of Cretaceous birds.

Yet, given its preserved state, they refrained from naming a new species based on this single bone.

In conclusion, this discovery, might not have answered all the questions regarding bird evolution, but it surely has opened up a new arena for possibilities and future discoveries.

Supporting the importance of fossils in piecing together the past, these artifacts from the Jurassic era have given us a glimpse into the true evolutionary journey of birds.

Baminornis zhenghensis and bird evolution

The discovery of Baminornis zhenghensis provides compelling evidence that bird evolution was already well underway by the late Jurassic period.

By bridging a crucial gap in the fossil record, these newly unearthed fossils reshape our understanding of how early birds diversified and adapted.

Scientists believe that such findings will continue to refine the evolutionary timeline, revealing more about the structural transformations that led to modern avian species.

Future excavations may yet unveil more missing pieces in the intricate puzzle of bird evolution.

The full study was published in the journal Nature.

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