What is "confuciusornithidae"

Confuciusornithidae is a family of primitive birds from the early Cretaceous Period of China. It consists of four genera. About half of all the confuciusornithid specimens, including representatives of all species, that have preserved feathers possess a pair of distinctive ribbon-like tail feathers, and possessed both shafted and non-shafted (downy) feathers.