At one time, it seemed silly to think that birds descended from dinosaurs. Now it's pretty well accepted, even though it's still hard to picture T. rex with feathers. As more fossils and more species are discovered, we get a glimpse into the weird twists and turns on the evolutionary path from reptile to bird. There are certain features we think of as avian, such as gizzard in place of teeth. But fossils of Hongshanornis, a bird only discovered in the 21st century, had both. According to a 2014 report on the most recently-found fossil, Hongshanornis has small teeth in both the upper and lower jaw.
What was Hongshanornis using those teeth to grip? Stomach stones offer a clue. Around the fossil bird’s pelvis sits a cluster of gastroliths – intentionally-swallowed pebbles that would have helped grind hard food. Since another Hongshanornis was preserved with a last meal of seeds preserved inside, Chiappe and colleagues suggest, the early bird probably plucked up hard foods that the gizzard stones broke down. Birds can’t chew, and such stones process their meals for them.
Despite the teeth and claws, though, Hongshanornis looked and flew very much like small birds that flit about today.
Brian Switek at Laelaps has more on this unusual creature.
(Image credit: Chiappe et al.)