Confuciusornis is a genus of basal crow-sized avialan from the Early Cretaceous Period of the Yixian and Jiufotang Formations of China, dating from 125 to 120 million years ago. Like modern birds, Confuciusornis had a toothless beak, but closer and later relatives of modern birds such as Hesperornis and Ichthyornis were toothed, indicating that the loss of teeth occurred convergently in Confuciusornis and living birds. It was thought to be the oldest known bird to have a beak, though this title now belongs to an earlier relative Eoconfuciusornis. It was named after the Chinese moral philosopher Confucius. Confuciusornis is one of the most abundant vertebrates found in the Yixian Formation, and several hundred complete specimens have been found.
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.
Iberomesornis is a monotypic genus of enantiornithine bird of the Cretaceous of Spain.
Yanornis is an extinct genus of fish-eating Early Cretaceous birds. Two species have been described, both from Liaoning province, China: Yanornis martini, based on several fossils found in the 120-million-year-old Jiufotang Formation at Chaoyang, and Yanornis guozhangi, from the 124-million-year-old Yixian Formation.
Jeholornis is a genus of avialans that lived between approximately 122 and 120 million years ago during the early Cretaceous Period in China. Fossil Jeholornis were first discovered in the Jiufotang Formation in Hebei Province, China and additional specimens have been found in the older Yixian Formation.
Longipteryx is a genus of prehistoric bird which lived during the Early Cretaceous. It contains a single species, Longipteryx chaoyangensis. Its remains have been recovered from the Jiufotang Formation at Chaoyang in Liaoning Province, China. Apart from the holotype IVPP V 12325 - a fine and nearly complete skeleton — another entire skeleton and some isolated bones are known to date.
Sapeornis is a monotypic genus of avialan which lived during the early Cretaceous period. Sapeornis contains only one species, Sapeornis chaoyangensis.
Hongshanornis is a genus of ornithuromorph birds known from early Cretaceous lake deposits of the Yixian Formation, Inner Mongolia, China. The holotype specimen, recovered in 2005, is currently held by the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing. It was found in the Jianshangou fossil beds, dated to 124.6 million years ago. Three additional specimens have been reported, though only one of those has been definitively identified as belonging to Hongshanornis. This latter specimen was found in the Dawangzhangzi fossil beds, which are about 122 million years old.
Confuciusornithidae is an extinct family of pygostylian avialans known from the Early Cretaceous, found in northern China. They are commonly placed as a sister group to Ornithothoraces, a group that contains all extant birds along with their closest extinct relatives. Confuciusornithidae contains four genera, possessing both shafted and non-shafted (downy) feathers. They are also noted for their distinctive pair of ribbon-like tail feathers of disputed function.
Eoalulavis is a monotypic genus of enantiornithean bird that lived during the Barremian, in the Lower Cretaceous around 125 million years ago. The only known species is Eoalulavis hoyasi.
Concornis is a genus of enantiornithean birds which lived during the early Cretaceous period, in the late Barremian age about 125 million years ago. Its remains are known from the Calizas de La Huérgina Formation at Las Hoyas, Cuenca province, Spain. The single known species, Concornis lacustris, was described from the remains of one fairly complete individual skeleton.
Sinornis is a genus of enantiornithean birds from the Lower Cretaceous Jiufotang Formation of the People's Republic of China.
Yixianornis is a bird genus from the early Cretaceous period. Its remains have been found in the Jiufotang Formation at Chaoyang dated to the early Aptian age, around 120 million years ago. Only one species, Yixianornis grabaui, is known at present. The specific name, grabaui, is named after American paleontologist Amadeus William Grabau, who surveyed China in the early 20th century.
Protopteryx is an extinct bird and the most basal enantiornithean, from the Cretaceous period. The type species is P. fengningensis. It was first discovered in the Sichakou Member of the Yixian Formation or Huajiying Formation of Hebei Province, northern China, dating from 131 Ma ago. Protopteryx has been found in the Daibeigou formation, as well. The name Protopteryx means "primitive feather": "proto-" meaning "the first of" and "-pteryx" meaning "feather" or "wing." The name comes from the fact that Protopteryx feathers are more primitive than those of modern birds, such as the two elongated tail feathers that lack barbs and rami.
The La Huérguina Formation is a geological formation in Spain whose strata date back to the Barremian stage of the Early Cretaceous. Las Hoyas is a Konservat-Lagerstätte within the formation, located near the city of Cuenca, Spain. The site is mostly known for its exquisitely preserved dinosaurs, especially enantiornithines. The lithology of the formation mostly consists of lacustrine limestone deposited in a freshwater wetland environment.
Longipterygidae is a family of early enantiornithean avialans from the Early Cretaceous epoch of China. All known specimens come from the Jiufotang Formation and Yixian Formation, dating to the early Aptian age, 125-120 million years ago.
Bohaiornithidae is a group of early predatory enantiornitheans from the early Cretaceous Period of China. All known specimens come from the Jiufotang Formation and Yixian Formation, dating to the early Aptian age, 125–120 million years ago. Bohaiornithidae was first coined as a family of enantiornithean birds by Wang and colleagues in 2014. They defined it as the natural group formed by all descendants of the common ancestor of the type species, Bohaiornis guoi, and Shenqiornis mengi.
Archaeornithura is an extinct genus of ornithuromorphs from the early Cretaceous period. It is known from two fossil specimens of a single species, Archaeornithura meemannae. The specimens have been dated to the Hauterivian age, 130.7 million years ago, making A. meemannae the oldest known ornithuromorph, the lineage that gave rise to modern birds, and contains all living birds as well as many of their extinct relatives.
Animals can go through certain changes. In the biology of birds and mammals, altricial species are those in which the young are underdeveloped at the time of birth, but with the aid of their parents mature after birth. Precocial species are those in which the young are relatively mature and mobile from the moment of birth or hatching. Precocial species are normally nidifugous, meaning that they leave the nest shortly after birth or hatching. These categories form a continuum, without distinct gaps between them.
