The Earliest Feathers from the Lower Cretaceous Dabeigou Formation of North Hebei: Implications for the Early Evolution of the Jehol Biota.

The Middle-Late Jurassic Yanliao Biota and the Early Cretaceous Jehol Biota in northeastern China are renowned for their numerous exceptional fossils of feathered non-avian dinosaurs and early avialans, which are pivotal for elucidating the origins and evolutionary trajectories of birds. The Early Cretaceous witnessed a rapid diversification of terrestrial biotas, with the Jehol Biota serving as one of the most typical and famous assemblages in China from this era. In this report, we present two isolated feather specimens recovered from the oldest sedimentary strata of the Dabeigou Formation, located within the Luanping Basin in northern Hebei Province, China. Both feather specimens are preserved as carbonized residues, and morphological analyses indicate that they represent some of the earliest feathered theropods from the Jehol Group reported to date, potentially including avian taxa. This discovery not only enriches the evidence for diverse terrestrial vertebrate groups of the Jehol Biota but also signifies the establishment of a complex ecosystem during the biota's early evolutionary stages.