Early bird winds back the avian clock

Modern birds may have evolved six million years earlier than thought, say palaeontologists after analysing the fossil remains of a previously unknown prehistoric relative.

Reconstruction of Archaeornithura meemannae, a specialised wading bird from
 the Early Cretaceous of China [Credit: Zongda Zhang]

The extinct species, of which two fossils were discovered in China's northeastern Hebei province about two years ago, is the oldest known relative of all birds alive today.

The fossils are described in the journal Nature Communications.

"The new fossil represents the oldest record (about 130.7 million years ago) of Ornithuromorpha," says study co-author Wang Min of the Chinese Academy of Sciences.

"It pushed back the origination date of Ornithuromorpha by at least five million years" and the divergence of modern birds by about the same margin.

The previous oldest known example of Ornithuromorpha lived about 125 million years ago.

The new bird, named Archaeornithura meemannae, shared many features with its modern cousins, apart from tiny, sharp claws on its wings.

Archaeornithura meemannae fossils [Credit: Chang et al/
Nature Communications]

It stood about 15 centimetres tall on two legs that had no feathers -- suggesting it may have been a wader from a lake shore environment.

The fossils were not complete enough to determine whether the creature had teeth -- a common feature of birds from the Early Cretaceous period, a sub-division of the Mesozoic era.

Like some modern birds, it may have used gastroliths, or stomach stones, to break down hard foods like seeds, and it was likely a plant-eater, says Wang.

Ornithuromorpha are believed to have comprised about half of bird species that lived during the Mesozoic era, which lasted from about 252 million to 66 million years ago. Some evolved into living birds.

Other Mesozoic groups like Enantiornithes, which had teeth and clawed wings, are not thought to have left any living descendents.

Mesozoic bird fossils are rare, and very little is known about the early evolutionary history of birds.

The earliest known relative of birds is thought to be Archaeopteryx, considered a transitional species from non-avian dinosaurs with feathers which lived about 150 million years ago.

Source: AFP [May 06, 2015]