The earliest and most basal ( `` primitive '' ) known oviraptorosaurs are Protarchaeopteryx robusta and Incisivosaurus gauthieri , both from the lower Yixian Formation of China , dating to about 125 million years ago during the Aptian age of the early Cretaceous period .
The earliest and most basal ( `` primitive '' ) known oviraptorosaurs are Protarchaeopteryx robusta and Incisivosaurus gauthieri , both from the lower Yixian Formation of China , dating to about 125 million years ago in the Lower Cretaceous .