It is the oldest-known member of the Ornithurae , the group which includes modern birds ( Neornithes ) and extinct related groups , such as Ichthyornis and Hesperornithes .
It is the oldest-known of the Ornithurae , the group which includes modern birds ( Neornithes ) and extinct related groups , such as Confuciusornis , Ichthyornis and Hesperornis .