A New Enantiornithid of the Mongolian Late Cretaceous, and a General Appraisal of the Infraclass Enantiornithes (aves)

Alexornis Alexornithidae Alexornithiformes Archaeopteryx Archaeornithes articular surface articulation assigned associated Aves axis Barun Goyot birds bones broad caudal characters Chiappe comparison complete compressed condition convex coracoid costal cotyla cranial crest Cretaceous deep depression derived developed diagnosis digit distal distal end dorsal Dzhyrakuduk Early edge eggshell elements elongate Enantiornithes Euornithiformes facet femur foramen Formation fossa fragments genera groove half Holotype humerus Khermeen known Kurochkin lack Late Cretaceous lateral length locality major mandible margin Maximum medial medial condyle metacarpal metatarsal minor Mongolia morphology Nanantius Nanantius valifanovi narrow Nessov Neuquenornis origin phalanges portion position possesses present preserved projection proximal end remarkably represented Sanz scapula separated shaft share short shows side similar skeleton slightly specimen sternal synsacrum tarsometatarsus thin tibiotarsus transverse trochlea Tsav tubercle ungual upper Uzbekistan valifanovi ventral vertebrae views Walker wide width Zhou Zhyraornis