A ceratopsian dinosaur from China and the early evolution of Ceratopsia.

Ceratopsians (horned dinosaurs) represent one of the last and the most diverse radiations of non-avian dinosaurs. Although recent systematic work unanimously supports a basal division of Ceratopsia into parrot-like psittacosaurids and frilled neoceratopsians, the early evolution of the group remains poorly understood, mainly owing to its incomplete early fossil record. Here we describe a primitive ceratopsian from China. Cladistic analysis posits this new species as the most basal neoceratopsian. This new taxon demonstrates that some neoceratopsian characters evolved in a more incremental fashion than previously known and also implies mosaic evolution of characters early in ceratopsian history.