Researchers led by Chicago's Field Museum discovered two new species of birds. One is toothless, called Meemannavis ductrix and the other a bizarre-looking ancient bird with a "movable chin." The latter lived over 120 million years ago and co-existed with the dinosaurs.
The team named the bird Brevidentavis zhangi, which means "short-toothed bird," and found its fossils approximately 80 miles (128 kilometers) from the westernmost reach of the Great Wall of China. Its movable chin was characterized by a bony appendage at the tip of its lower jaw. The dental feature had not been seen in any dinosaurs.
120-Million-Year-Old Bird Fossils With Movable Chin Found Near the Great Wall of China
The Painstaking Process of Identifying Ancient Bird Fossils
The two new species both belong to ornithuromorph birds that include modern birds, MailOnline reported. In modern-day, Meemannavis is also toothless, while Brevidentavis has small, peg-like teeth packed together along with a strange movable chin.
Study lead author Jingmai O'Connor, the museum's associate curator of vertebrate paleontology, said that it was a long and painstaking process in identifying the new species because of the unique appendage that Brevidentavis has. It is an ornithuromorph bird with teeth and a little bone at the front of its jaw called the predentary, where a chin would be present if only birds had chins.
A previous study from the researchers showed that predentary bones underwent stress and found a special kind of cartilage to form into something new when there was movement. O'Connor said that they found predentary can move and would have been innervated, which means Brevidentavis were able to move it and feel through it.
This additional feature may have helped the ancient bird detect prey and use their movable pincer at the tip of their jaws in front of their teeth to capture their food.
All Birds Are Dinosaurs, But Not All Dinosaurs Are Birds
Although all birds are dinosaurs, not all dinosaurs are birds. SciTech Daily reported that only a small group of dinosaurs evolved into birds and co-existed with other dinosaurs for more than 90 million years. Out of all dinosaur species, they were the only ones who survived extinction and went on to evolve into modern birds.
But many of the prehistoric birds also went extinct, according to O'Connor's, whose work focuses on studying the field. For more than 20 years, scientists have discovered over 100 specimens of fossil birds near the Great Wall of China in which most of them likely lived during the time of the dinosaurs.
The Changma site, where they found a skull, is an important place for researchers studying bird evolution because it is the second-richest Mesozoic fossil bird site in the world. Half of the fossils discovered there belonged to one species called Gansus yumenensis. That means determining which fossils do not belong to this group is tricky.
Study co-author Matt Lamanna from the Carnegie Museum of Natural History said that looking for fossils in Changma is likely turning back the pages of history through uncovering animals and plants layer by layer that has never seen the light of day in roughly 120 million years.
Study co-author Jerry Harris from Utah Tech University said that these fossils from the Changma site in China were closely related to modern birds. He noted that the new skull specimens they found fill the gap from previous discoveries that only found bodies without skulls.
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