1/ STOKED to share our new study in @nature, unveiling the oldest-known modern bird fossil! . We name the new fossil Asteriornis, but have been affectionately calling it the Wonderchicken. @EarthSciCam @christs_college 
2/ Please check out the paper here, as well as the supplement which includes a LOT: 136 pages of additional text, phylogenetic data, 3D models, raw CT scans, and videos. nature.com/articles/s4158…
3/ Huge thanks to @pmk_illustrator for this gorgeous painting of Asteriornis in its natural habitat. This part of Europe was covered by a warm sea 66.7 million years ago, and limb proportions and habitat suggest Asteriornis might have had a shorebird-like ecology.
4/ Asteriornis comes from the end of the Age of Dinosaurs, 66.7 million years ago. It pre-dates the asteroid impact at the end of the Cretaceous by about 700,000 years, meaning it roamed the earth at the same time as T. rex and Triceratops on land, and giant mosasaurs in the sea.
5/ We were shocked to discover the fossil skull while CT scanning a block of rock containing a leg bone. Amazingly, the skull was just below the surface of the rock, about 1 mm beneath the femur!
6/ This is one of the best fossil bird skulls out there—the skull is nearly complete and preserved in 3D! It shows a number of features similar to chickens and a number of features similar to ducks!
7/ This combination of features tells us that Asteriornis is close to the most recent common ancestor of the group that includes chickens and ducks today—a group called Galloanserae. This is one of the most deeply diverging groups of modern birds!
8/ Amazingly, the fossil was found in Europe! This makes it the first confirmed record of a modern bird from the Age of Dinosaurs ever found in the northern hemisphere. This raises important questions about where on Earth modern birds originated during the Age of Dinosaurs.
9/ More specifically, it was found in Belgium just across the border with The Netherlands, in rocks from the Type Maastrichtian (the official reference for rocks from the end of the Cretaceous). This locality is famous for mosasaurs and giant sea turtles, but not birds!
10/ In fact, this is only the 2nd substantial bird fossil found from this locality despite hundreds of years of searching. The previous one was relative of Ichthyornis, which still retained teeth! The new find is the first evidence of co-occurring modern and pre-modern birds.
11/ This project is the culmination of an exciting collaboration with John Jagt (NHMM), @KsepkaLab (Bruce Museum), and my amazing PhD students @J_BenitoMoreno and @albertonykus (Cambridge).
12/ We had planned an exhibit at the @SedgwickMuseum to mark the ‘Dawn of the Wonderchicken’. Due to COVID this has been postponed. But we are working on a way to get the exhibit online so everyone can learn about this great new fossil. Stay safe and healthy, everyone!
