"This was clearly a hotspot of ancient bird biodiversity," Chiappe told LiveScience.
The newly discovered bird, a robin-size creature called Sulcavis geeorum, lived between 121 million and 125 million years ago. Sulcavis geeorum belonged to a class of extinct toothed birds called Enantiornithines, which were the most numerous birds during the age of dinosaurs. The diminutive creature looked somewhat similar to modern-day songbirds, with a key difference: the bird had some very strange teeth. (Album: 25 Amazing Ancient Beasts)
The teeth of this tiny flier had sharp, pointy crowns. In addition, the fossil found by Chiappe's team had preserved tooth enamel that formed serrated ridges. Those serrated ridges probably enabled the birds to crack open the hard exoskeletons of insects, crabs or snails, Chiappe said.
The strange teeth may shed light on a prehistoric mystery of sorts: No one knows exactly why early birds had teeth. It's also unclear why they have lost their teeth at least four times since they first emerged in the fossil record. In fact, modern-day birds still have genes for teeth, but the genes are turned off, Chiappe said.