The Enantiornithes, also known as enantiornithines or enantiornitheans in literature, are a group of extinct avialans, the most abundant and diverse group known from the Mesozoic era. Almost all retained teeth and clawed fingers on each wing, but otherwise looked much like modern birds externally. Over eighty species of Enantiornithes have been named, but some names represent only single bones, so it is likely that not all are valid. The Enantiornithes became extinct at the Cretaceous–Paleogene boundary, along with Hesperornithes and all other non-avian dinosaurs.
Gansus is a genus of aquatic birds that lived during the Aptian age of the Early Cretaceous (Aptian-Albian) period in what are now Gansu and Liaoning provinces, western China. The rock layers from which their fossils have been recovered are dated to 120 million years ago. It was first described in 1984 on the basis of an isolated left leg. 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.
The Xiagou Formation is the middle strata of the Xinminbao Group. It is named for its type site in Xiagou, in the Changma Basin of Gansu Province, northwestern China and is considered Early Cretaceous in age. It is known outside the specialized world of Chinese geology as the site of a Lagerstätte in which the fossils were preserved of Gansus yumenensis, the earliest true modern bird.
The Xīnmínbǎo Group is a group of geological formations in north central China. They occur across a large depression between the Altai mountains of Mongolia to the north and the Qilian mountains of the Qinghai Plateau to the south, in the Gōngpóquán (公婆泉) and Suànjǐngzi (算井子) basins, and also in the neighbouring Jiuquan Basin.
Suzhousaurus is a genus of large therizinosauroid dinosaur from the Early Cretaceous of China. The genus is known from two specimens discovered on the Xiagou Formation and Zhonggou Formation—which are situated in the Xinminbao Group. These findings were made during field-works in 1999 and 2004. Though Suzhousaurus is known from these two specimens, an earlier named and described therizinosauroid from the adjacent basin, "Nanshiungosaurus" bohlini, may be synonymous with the former. However, Suzhousaurus can not be compared to this species due to non-overlapping material and the loss of the same. Moreover, this synonymy will result in Suzhousaurus bohlini with "N". bohlini having priority.
The Hekou Group is a geological group in Gansu Province, China. It is Early Cretaceous in age. Many dinosaur fossils have been recovered from the Hekou Group, including iguanodonts, large sauropods, and armored dinosaurs. Fossil eggs are rare, but one oogenus, Polyclonoolithus, was discovered in the Hekou Group. Extensive fossil tracks belonging to pterosaurs and dinosaurs have also been described. The group spans the Valanginian to Albian and can be subdivided into four formations.
Xiongguanlong is an extinct genus of tyrannosauroid theropod from the Early Cretaceous period of what is now China. The type and only species is X. baimoensis. The generic name comes from Jiayuguan City and the Mandarin word "long" which means dragon. The specific epithet, "baimoensis" is a latinization of the Mandarin word for "white ghost" in reference to one of the geological features of the type locality.
Hongshanornithidae is an extinct group of early ornithuromorph birds from the early Cretaceous period of China. It includes the genera Hongshanornis and Tianyuornis from the Yixian Formation of Inner Mongolia, Longicrusavis from the Yixian Formation of Liaoning Province, Parahongshanornis from the Jiufotang Formation of Liaoning Province, and Archaeornithura, the oldest known member, from the Huajiying Formation of Hebei Province.
Songlingornithidae is a family of basal euornithean dinosaurs from the Early Cretaceous of China. All known specimens come from the Jiufotang Formation and the Yixian Formation, dating to the early Barremian and Aptian ages, 125–120 million years ago.
Xuwulong is a genus of hadrosauroid dinosaur from the Early Cretaceous period. It lived during the early Cretaceous period in what is now Yujingzi Basin in the Jiuquan area, Gansu Province of northwestern China. It is known from the holotype – GSGM F00001, an articulated specimen including a complete cranium, almost complete axial skeleton, and complete left pelvic girdle from Xinminpu Group. Xuwulong was named by You Hailu, Li Daqing and Liu Weichang in 2011 and the type species is Xuwulong yueluni; the binomial name as a whole refers to Professor Wang Yue-lun; "Xu-wu" is his courtesy name.
Qiliania is an extinct genus of early bird from the lower Cretaceous about 120 million years ago. It is an enantiornithean which lived in what is now Gansu Province, north-western China. It is known from two incomplete, semi-articulated and three-dimensionally preserved skeletons, which were found in the Xiagou Formation of the Changma Basin. It was first named by Shu-An Ji, Jessie Atterholt, Jingmai O'Connor, Matthew Lamanna, Jerry Harrs, Li Da-Qing, You Hai-Lu and Peter Dodson in 2011 and the type species is Qiliania graffini. The species was named for Greg Graffin, a paleontologist and member of the punk rock group Bad Religion, at the suggestion of coauthor Jingmai O'Connor, a longtime fan of the band.
Euornithes is a natural group which includes the most recent common ancestor of all avialans closer to modern birds than to Sinornis.
Ambiortiformes is a group of prehistoric ornithuromorph dinosaurs.
Yumenornis is an extinct genus of basal ornithuromorph dinosaurs known from the Early Cretaceous Xiagou Formation of Changma Basin, Gansu Province of northwestern China. Yumenornis was first named by Ya-Ming Wang, Jingmai O'Connor, Da-Qing Li and Hai-Lu You in 2013 and the type species is Yumenornis huangi.
Changmaornis is an extinct genus of basal ornithuromorph dinosaur known from the Early Cretaceous Xiagou Formation of Changma Basin, Gansu Province of northwestern China. Changmaornis was first named by Ya-Ming Wang, Jingmai K. O'Connor, Da-Qing Li and Hai-Lu You in 2013 and the type species is Changmaornis houi.
Dunhuangia is a bird genus, belonging to the Enantiornithes, which during the Early Cretaceous lived in the area of present China.
Feitianius is a bird genus, belonging to the Enantiornithes, that during the Early Cretaceous lived in the area of modern China. A single species has been named in the genus, Feitianius paradisi.
Meemannavis is a genus of ornithuromorph dinosaurs from the Early Cretaceous (Aptian) Xiagou Formation of Gansu Province, China. The genus contains a single species, Meemannavis ductrix, known from a partial skeleton including an incomplete skull and cervical and thoracic vertebrae. The lower jaw and tip of the upper jaw of the Meemannavis holotype are toothless, but it may have had teeth nearer the back of the upper jaw.
Brevidentavis is a genus of ornithuromorph dinosaurs from the Early Cretaceous (Aptian) Xiagou Formation of Gansu Province, China. The genus contains a single species, Brevidentavis zhangi, known from a specimen including a partial skull and cervical vertebrae. The Brevidentavis holotype shows unusually blunt teeth in its lower jaw, which the describing authors suggest may indicate a specialized diet. Its dentition shows similarities with those of hesperornitheans, and indeed it may be an early member of that group.
