Exceptional preservation and foot structure reveal ecological transitions and lifestyles of early theropod flyers

This research paper investigates the evolutionary ecology of early theropod flyers by analyzing their foot morphology, including toe pads, foot scales, claws, and joints. Using laser-stimulated fluorescence and traditional morphometrics, the authors compare fossil foot data to that of modern birds to infer lifestyles. Jurassic flyers (*Anchiornis* and *Archaeopteryx*) show ground-dwelling adaptations, while Early Cretaceous flyers display more aerial lifestyles. Some early birds exhibited complex ecologies unlike modern birds. Unexpectedly, *Microraptor*, a non-bird flyer, shows specialized raptorial adaptations, suggesting non-bird flyers filled ecological niches now occupied by birds.

Michael Pittman, Phil R. Bell, Case Vincent Miller, Nathan J. Enriquez, Xiaoli Wang, Xiaoting Zheng, Leah R. Tsang, Yuen Ting Tse, Michael Landes, Thomas G. Kaye