Missing the Flight
Rice, Judy, Natural History
The plot continues to thicken when it comes to bird evolution and the origin of flight. Eosinopteryx brevipenna is the latest feathered, birdlike theropod dinosaur to emerge from rich sites in Liaoning Province in northeast ern China. While a diverse group of such creatures have been found in Early Cretaceous deposits, Eosinopteryx is older, dating from the mid- to late Jurassic period, roughly 155 million to 150 million years ago. Along with Anchiornis, another recently described Jurassic specimen of similar body plan, Eosinopteryx shows that, even at an early evolutionary stage, birdlike dinosaurs occupied different niches in the same ecosystem.
Pascal Godefroit of the Royal Belgian Institute of Natural Sciences in Brussels and Gareth Dyke, of the University of Southampton, England, along with four colleagues, described the attributes of the adult-or nearly adult- Eosinopteryx fossil from a complete skeleton finely preserved in slate. The pigeonsize animal is remarkable for its lack of flight feathers, in contrast with Anchiornis, which even on its lower legs bore the stiff, asymmetric feathers that could have enabled it to generate lift and fly or glide. …