Scientists Uncover Unusual New Species That Survived Dinosaur Extinction, Dubbed "Attenborough's Strange Bird"

A novel type of fossil bird, christened Imparavis attenboroughi, has been uncovered by scientists. This species is unique in being the first recognized to have evolved without teeth. An image displaying the fossilized skeleton of Imparavis attenboroughi, alongside a recreation of the living bird is credited to Ville Sinkkonen.

While no living birds have teeth, this wasn't always the state of affairs. Many early fossil birds possessed beaks replete with small, sharp teeth. A manuscript in the publication Cretaceous Research outlines a novel type of fossil bird which is the pioneer of its species to evolve without teeth. Named in honor of naturalist Sir David Attenborough, the moniker translates to “Attenborough’s strange bird.”

Sir David Attenborough stated that it’s a significant honor to have a fossil, especially one as remarkable and crucial as this, named after oneself. He added that the history of birds is more complicated than previously understood.

All birds are categorized as dinosaurs, but not every dinosaur belongs to the specialized category known as birds. Basically, while every square is a rectangle, not all rectangles are squares. The recently-described Imparavis attenboroughi is both a bird and a dinosaur.

The enantiornithines, or “opposite birds,” counted Imparavis attenboroughi amongst their ranks. Named for the “opposite” feature observed in their shoulder joints compared to that seen in contemporary birds, the enantiornithines were once the most diverse bird variety, but they all died out following the meteor impact that wiped out the majority of dinosaurs around 66 million years ago. Research is ongoing to uncover the reasons behind the enantiornithine extinction and the survival of the ornithuromorphs, the group that led to modern birds.

Alex Clark, a Ph.D. student from the University of Chicago and the Field Museum, and corresponding author of the paper stated that enantiornithines are incredibly unusual as most had teeth and claw-like digits. He recounted that if one could travel 120 million years back in time to northeastern China, one might have seen a creature resembling a robin or a cardinal, but upon opening its mouth and lifting its wing, its dental palate and small fingers would become evident.

However, “Attenborough’s strange bird” was different. Clark stated that scholars originally speculated that the first enantiornithine evolved to be toothless around 72 million years ago, in the late Cretaceous. However, Imparavis pushes this timeline backward by approximately 48 to 50 million years, indicating that this group evolved to become toothless much earlier than previously considered.

Field Museum and University of Chicago Ph.D. student Alex Clark was involved in describing the fossil, Imparavis attenboroughi. Credit for the image goes to Alex Clark.

Discovered near the village of Toudaoyingzi in northeastern China by an amateur fossil collector, the specimen was given to the Shandong Tianyu Museum of Nature. Jingmai O’Connor, Field Museum associate curator of fossil reptiles, co-author of the paper, and Clark’s advisor, noticed something different about the fossil when visiting the Shandong Tianyu Museum’s collections.

O’Connor shared that she was drawn impelled to examine the specimen not because of its lack of teeth, but its forelimbs which featured a sizeable bicipital crest – a bony extension at the top of the upper arm bone where muscles attach. She had observed crests like that only in Late Cretaceous birds. This piqued her interest and made her think it might be a new species.

Co-authors based in China joined O’Connor and Clark for further study of the specimen and confirmed that it represented an organism previously unknown to science.

The peculiar wing bones probably facilitated strong muscular attachments that allowed the bird to flap its wings powerfully. Some traits of the bones are similar to those of modern birds such as puffins or murres, which can flap their wings extremely quickly, and quails and pheasants, which despite being comparatively small, can generate enough power to lift vertically almost instantly when threatened.

Clark explains that the bird’s lack of teeth doesn't necessarily provide information about its diet since contemporary toothless birds consume a spectrum of food. Unlike modern birds, and similarly to other enantiornithines, it does not seem to possess a digestive organ called a gizzard, or gastric mill, which aided in breaking down food.

While Clark notes that “an animal is more than the sum of its parts, and we can’t fully know what an animal’s life was like just by looking at single components of its body,” he and his coauthors have been able to hypothesize about some of Imparavis’s behavior and ecology, based on the details of its wings, feet, and beak together. “I like to think of these guys kind of acting like modern robins. They can perch in trees just fine, but for the most part, you see them foraging on the ground, hopping around and walking,” says Clark.

“It seems like most enantiornithines were pretty arboreal, but the differences in the forelimb structure of Imparavis suggests that even though it’s still probably lived in the trees, it maybe ventured down to the ground to feed, and that might mean it had a unique diet compared to other enantiornithines, which also might explain why it lost its teeth,” says O’Connor.

In the paper, the researchers also revisited a previously described fossil bird, Chiappeavis (which O’Connor named eight years ago after her Ph.D. advisor), and suggest that it too was an early toothless enantiornithine. This finding, along with Imparavis, indicates that toothlessness may not have been quite as unique in Early Cretaceous enantiornithines as previously thought.

Clark said that nature documentaries by Sir David Attenborough, in which the renowned British naturalist narrates the behavior of different animals, were pivotal to his own interest in science. “I most likely wouldn’t be in the natural sciences if it weren’t for David Attenborough’s documentaries,” says Clark, explaining why he chose to name the new fossil after Attenborough.

Clark and O’Connor noted the importance of Attenborough’s messaging that not only celebrates life on earth, but also warns against the mass extinction the planet is undergoing due to human-caused climate change and habitat destruction.

“Learning about enantiornithines like Imparavis attenboroughi helps us understand why they went extinct and why modern birds survived, which is really important for understanding the sixth mass extinction that we’re in now,” says O’Connor. “The biggest crisis humanity is facing is the sixth mass extinction, and paleontology provides the only evidence we have for how organisms respond to environmental changes and how animals respond to the stress of other organisms going extinct.”