Early Birds

Birds and their ancestors have been on Earth for a very long time. Descending from feathered dinosaurs known as theropods, these animals can trace their lineage back 230 million years, to the Triassic. We know that theropods eventually gave way to Archaeopteryx in the late Jurassic, about 150 million years ago, whose descendants eventually evolved into two major lineages during the Cretaceous: Enantiornithes and Ornithuromorpha. Only Ornithuromorpha survived the extinction event that wiped out all of the dinosaurs 66 million years ago, giving rise to all bird species on our planet now.

In a paper published today in Nature Communications, researchers describe the oldest known fossil of Ornithuromorpha—a new species called Archaeornithura meemannae. The description is based on two well-preserved fossils collected from deposits in the Sichakou basin in Hebei, northeastern China (where many preserved fossils have been discovered), dating to 130 million years ago! (The next oldest fossil dates back to 125 million years ago.)

The fossils have a near-completely preserved plumage with anatomical features characteristic of aerodynamic physiology and maneuverability during flight. The absence of feathers on the upper leg, or tibiotarsus, indicates the species also spent a lot of time in the water, a wading lifestyle, consistent with other fossil bird species found in similar deposits.

The finding is important, explains the Academy’s bird expert, Jack Dumbacher. “Our fossil record from this time is still pretty scant, but these Chinese fossil beds are revealing some very interesting stuff from this era. The tree in the paper is the important thing… [Since the paper is open access, you can view the tree here.] It was not clear when the Ornithimorphae first appeared, and interestingly, this paper describes the earliest known representative from this group—or another way to look at it, it shows that birds with Ornithomorphae characteristics—were around 130.7 Million years ago! This is pretty old, considering that Archaeopteryx was 150 million years ago or so, which suggests that the early birds evolved rapidly and diversified tremendously in a short amount of time.”

Image: A reconstruction of Archaeornithura meemannae. Credit: Zongda Zhang