The Archaeopteryx is one of evolution’s most infamous species—but it’s also a very confusing creature. All present-day birds are technically dinosaurs, but the 150-million-year-old, raven-sized hunter is the earliest known example of an avian animal. At the same time, Archaeopteryx lived durin g the Jurassic Period among multiple other feathered dinosaurs that were not birds in the true sense of the term. But if it’s any consolation, it’s often still difficult for paleontologists to tell them apart, too. “For a long time, there have been very few things that we could say really characterize the transition from terrestrial dinosaurs to flying bird dinosaurs,” explained Jingmai O’Connor, the associate curator of fossil reptiles at Chicago’s Field Museum. O’Connor and her team spent over a year carefully preparing and examining the museum’s own Archaeopteryx specimen after its arrival in 2022. In a study published on February 2nd in the journal The Innovation, the team described a set of newly analyzed anatomical features that help set the iconic bird dinosaur apart from its fellow winged (but nonflying) relatives. As it turns out, some of the strangest attributes of today’s birds are traceable all the way back to the very first bird. “These weird little features in the mouth of Archaeopteryx, that are also found in living birds, are giving us new criteria that we can use to tell whether a dinosaur fossil is a bird or not,” said O’Connor. Led by chief fossil preparator Akiko Shinya, the paleontologists slowly alternated between removing the topmost layer of limestone from the fossils and checking the integrity of any exposed features. Fossilized soft tissues like feathers and skin will glow under UV light in certain rocks, allowing Shinya’s group to constantly assess the preserved details. These fragments are extremely small and easy to overlook given Archaeopteryx’s size, but the scientists still managed to identify strange, never-before-seen details. “They showed me these tiny, glowing dots, and I had no idea what we were looking at,” remembered O’Connor. After consulting avian anatomy references, she noticed a striking similarity between the fossil dots and what are known as oral papillae. These small, fleshy conical structures are located on the roof of mouths in present-day birds. They function similarly to teeth in humans, helping guide food down the animal’s throat while keeping it away from their windpipe. O’Connor and her colleagues now believe these are the first documented examples of oral papillae in the fossil record—all within evolution’s first true bird. Other discoveries included other telltale features seen in today’s birds, including what appears to be the splinter of a tongue bone. Humans don’t have any bones in their tongues, but they do occur in most avian species and help them grab and manipulate food. “This teeny-tiny bone is one of the smallest bones in the body, and it indicates that Archaeopteryx had a highly mobile tongue, like many birds today,” said O’Connor. CT scans also indicate Archaeopteryx had nerve endings in the end of its beak—part of what’s known as a bill-tip organ. Again, many existing birds have also evolved this system, which helps them nuzzle around the ground for food. These latest discoveries make a great deal of sense when considered in a wider evolutionary timeline. Flying is very energy intensive, so birds possess some of the most efficient digestive systems on the planet. The development of oral papillae, tongue bones, and bill-tip organs would have all benefited the Archaeopteryx’s new caloric requirements—so much so that the traits appear to have remained in avian dinosaurs for millions of years.  “These discoveries show this really clear shift in how dinosaurs were feeding when they started flying and had to meet the enormous energetic demands of flight,” said O’Connor. The post Weird bird mouths go all the way back to the first avian dinosaur appeared first on Popular Science. ...read more read less