Fossil Named 'Attenborough's Strange Bird' Was the First in Its Kind without Teeth
Published:25 Apr.2024    Source:Field Museum
All birds are dinosaurs, but not all dinosaurs fall into the specialized type of dinosaurs known as birds, sort of like how all squares are rectangles, but not all rectangles are squares. The newly described Imparavis attenboroughi is a bird, and therefore, also a dinosaur. Imparavis attenboroughi was a member of a group of birds called enantiornithines, or "opposite birds," named for a feature in their shoulder joints that is "opposite" from what's seen in modern birds.
Scientists previously thought that the first record of toothlessness in this group was about 72 million years ago, in the late Cretaceous. This little guy, Imparavis, pushes that back by about 48 to 50 million years. So toothlessness, or edentulism, evolved much earlier in this group than scientists thought. It had a giant bicipital crest -- a bony process jutting out at the top of the upper arm bone, where muscles attach. I'd seen crests like that in Late Cretaceous birds, but not in the Early Cretaceous like this one. Meanwhile, the bird's toothless beak doesn't necessarily tell scientists what it was eating, since modern toothless birds have a wide variety of diets.

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, authors have been able to hypothesize about some of Imparavis's behavior and ecology, based on the details of its wings, feet, and beak together. 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.