Near the Great Wall of China, two new species of dinosaur-era dinosaur-era dinosaur-era dinosaur-era dinosaur-era dinosaur-era dinosaur-era dinosaur-era dinosaur-era dinosaur-era dinosaur-era dinosaur-era dinosaur-era dinosaur-era One of the new species has a sensitive, moveable bony appendage at the tip of its lower jaw, which it may have used to locate food.
Paleontologists discovered evidence of an even older planet around 80 miles from the westernmost stretch of China’s Great Wall. Over the previous two decades, scientists have discovered more than 100 fossil birds from the period of the dinosaurs, which lived around 120 million years ago. Many of these fossils, however, have been difficult to identify since they are fragmentary or heavily crushed. Researchers analyzed six of these fossils and discovered two new species in a recent report published in the Journal of Systematics and Evolution. One of the new species featured a moveable bony attachment at the tip of its lower jaw, which might have assisted the bird in digging for food.
Jingmai O’Connor, the study’s main author and assistant curator of vertebrate paleontology at Chicago’s Field Museum, says, “It was a lengthy, tedious process piecing out what these creatures were.” “However, these new fossils contain two new species that expand our understanding of Cretaceous bird faunas, and we discovered dental traits in these dinosaurs that we’ve never seen before.”
“These fossils originate from a location in China that has generated fossils of birds that are pretty damned similar to current birds,” says co-author Jerry Harris of Utah Tech University. “However, none of the bird fossils documented so far have had heads preserved with the bodies.” “These new skull specimens contribute to our understanding of the birds from this site, as well as avian evolution in general.”
All birds are dinosaurs, but not all dinosaurs are birds; a small subset of dinosaurs developed into birds during 90 million years of coexistence with other dinosaurs. Modern birds are descended from a group of birds that survived the catastrophe that wiped out the dinosaurs, although many ancient birds perished as well. O’Connor’s research focuses on diverse types of early birds to see why some survived and others died out.
Changma, a fossil site in northeastern China, is crucial to academics like O’Connor who study bird evolution. It’s the world’s second-richest Mesozoic (Dinosaur Age) bird fossil site, although more than half of the fossils discovered there are from the same species, Gansus yumenensis. It’s difficult to tell which fossils are Gansus and which aren’t; the six specimens reviewed by O’Connor and her colleagues are mostly heads and necks, which aren’t preserved in known Gansus specimens. The fossils had also been smushed by their time down below, making analysis difficult.
“The Changma site is a rare spot,” says Matt Lamanna of the Carnegie Museum of Natural History in Pittsburgh, who was a research co-author. “Along ancient bedding planes, the fossil-bearing rocks tend to fracture into thin sheets. So, while you’re excavating, it’s as if you’re really turning back the pages of history, unearthing creatures and plants that haven’t seen the light of day in around 120 million years.”
“Because the specimens were flattened, CT-scanning and fully segmenting them could take years and might not even give you that much information,” says O’Connor. “Because these thin bones are flattened into almost the same plane, it’s almost impossible to figure out where the boundaries of these bones are.” “As a result, we had to work with what was revealed.” The researchers were able to identify critical traits in the birds’ jaws via meticulous effort, revealing that two of the six species were previously unknown to science.
Meemannavis ductrix and Brevidentavis zhangi are the names of two new species (or, more precisely, genera) in the Meemannavis ductrix and Brevidentavis zhangi genera. Meemannavis is named after Meemann Chang, a Chinese paleontologist who led the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) in Beijing for the first time. Brevidentavis means “short-toothed bird” in Latin. Meemannavis and Brevidentavis, like Gansus, are ornithuromorph birds, which includes contemporary birds. Meemannavis had no teeth, like like today’s birds. Brevidentavis, on the other hand, had a mouth full of short, peg-like teeth packed tightly together. Along with those teeth, there was another oddity.
“Brevidentavis is an ornithuromorph bird with teeth, and in ornithuromorphs with teeth, there’s a small bone at the front of the jaw called the predentary, which is where the bird’s chin would be if birds had chins,” O’Connor adds. By CT-scanning the bone and coloring it with chemicals, the scientists discovered that the predentary bone endured stress, as well as a kind of cartilage that only develops when there is movement, in a prior work on the predentary in another prehistoric bird.
“We were able to tell in this previous work that the predentary could be moved and that it would have been innervated — Brevidentavis wouldn’t only have been able to move its predentary, it would have been able to feel via it,” O’Connor adds. “It might have aided in the detection of prey. We may assume that these toothed birds had small beaks with moveable pincers at the tip of their jaws in front of their teeth.”
Brevidentavis isn’t the first fossil bird to be found with a predentary that may have been utilized in this fashion, but its discovery, together with that of Meemannavis, adds to our knowledge of ancient bird variety, particularly in the Changma area.
The research also sheds insight on Gansus, the most prevalent bird at the site, since at least four of the other specimens analyzed are most likely of this species. “Gansus is the first truly Mesozoic bird in the world,” says Hai-Lu You of the IVPP. “As Archaeopteryx is more dinosaur-like, we now know what its skull looks like after around 40 years.”
“These magnificent relics are like a lockpick,” says Tom Stidham, a co-author from the IVPP, “enabling us to unlock the door to better understanding of the evolutionary history of the skull in near relatives of extant birds.” “These birds evolved at a period when huge dinosaurs still roamed the planet, experimenting with varied lifestyles in the water, the air, and on land, as well as different diets, as shown by some species having or without teeth. Only a few fossils from this geological period have the amount of anatomical detail shown in these old bird skulls.”
“These findings support the concept that the Changma site is unique in that ornithuromorph birds predominate, which is rare in the Cretaceous,” adds O’Connor. “Knowing about the ancestors of present birds may help us understand why certain birds survived while others did not.”