Modern birds may be six million older than previously thought according to palaeontologists in China. The recent discovery of two fossils, in the northeastern Hebei province, are the oldest known members of the group Ornithuromorpha.

That group is the ancestor of the now extinct Hesperornithes, toothed birds of the Cretaceous period, as well as Neornithes or modern birds as we know them. This latest discovery pushes back the evolutionary branching of the two types.

Based on the age of the rocks surrounding the fossils, the birds lived about 130 million years ago, at least five million years older than any other known Ornithuromorpha.

Birds are thought to have begun to diverge from dinosaurs about 150 million years ago and the end of the Jurassic period. The date, however, is difficult to nail down specifically. Bird fossils, because they are light and hollow, generally do not preserve well and are more rare than other types of fossils.

According to Rachel Feltman of the Washington Post, the latest discovery suggest that there were even older members of the lineage of birds. “In fact, it seems more bird-like than other, later members of Ornithuromorpha, which probably means these birds have an older-yet ancestor in common that’s waiting to be discovered. With a common Ornithurae ancestor a few million years back, there’d be time for multiple branches of lineage to emerge, with some adapting modern qualities more quickly than others,” she writes.

It was not until the mid 1990s that the first non-avian dinosaurs with preserved feathers were found. Since then dozens of dinosaur species have been found to have been feathered. A study published in 2014 suggests that all dinosaurs may have been feathered from their first appearance.

Dinosaurs described at that time, Kulindadromeus, dated back 220 million years, about 11 million years after dinosaurs first appeared and clearly showed the presence of feathers on the animals arms and legs.

According to a report published in the journal Nature Communications, the new
species, Archaeornithura meemannae, were found in the Sichakou basin. The researchers report that the fossils were well preserved, revealing a great deal of detail about the animals.

This latest addition to the bird family tree was about 6 inches high. Its featherless legs suggest that it was a wader, feeding in shallow water but the size and shape of its bones suggest that A. meemannae was an agile flyer.

“The new bird is quite derived and has many advanced features of modern birds, and thus is far away from the transitional history of dinosaurs-birds. The most primitive bird of Ornithuromorpha is most likely from older deposits than what we discovered now,” said study co-author Wang Min of the Chinese Academy of Sciences. 

Birds provide an important lesson in how “evolution by natural selection” works. There is a tendency among many people to think of it as “survival of the fittest” but that isn’t really how it works. A more accurate description would be “survival of the species best able to adapt”. Ornithuromorpha were fairly minor players in the age of the dinosaurs but they were the only dinosaurs and one of the few species of any type who were able to pass their DNA into the modern age.

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