A new jeholornithiform identified from the Early Cretaceous Jiufotang Formation in western Liaoning

A new specimen of jeholornithiform was identified from the Early Cretaceous Jiufotang Formation in Chaoyang of Liaoning Province.This specimen shows typical characters of Jeholornithiformes, such as the long bony tail composed of about 28 free caudal vertebrae, the middle and posterior caudal vertebrae elongated antero-posteriorly, the edentulous premaxilla, and the dentary with a straight ventral margin posteriorly and a robust anterior end expanded ventrally.It differs from all other jeholornithiforms in the following unique combination of features: the relatively undeveloped deltopectoral crest of the humerus, the straight third metacarpal, which forming a small gap with the second metacarpal, the largest hallux ungula, and the undeveloped chevrons and zygapophyses of the caudal vertebrae.On the basis of unique characteristics and comparisons with other jeholornithiforms, a new genus and species(Neimengornis rectusmim gen.et sp.nov.) were erected.The identification of Neimengornis rectusmim further enriches the diversity of jeholornithiforms and sheds new light on understanding the morphology and classification of this clade.