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.
Hesperornis is a genus of cormorant-like Ornithuran that spanned throughout the Campanian age, and possibly even up to the early Maastrichtian age, of the Late Cretaceous period. One of the lesser-known discoveries of the paleontologist O. C. Marsh in the late 19th century Bone Wars, it was an early find in the history of avian paleontology. Locations for Hesperornis fossils include the Late Cretaceous marine limestones from Kansas and the marine shales from Canada. Nine species are recognised, eight of which have been recovered from rocks in North America and one from Russia.
Azhdarchidae is a family of pterosaurs known primarily from the Late Cretaceous Period, though an isolated vertebra apparently from an azhdarchid is known from the Early Cretaceous as well. Azhdarchids are mainly known for including some of the largest flying animals discovered, but smaller cat-size members have also been found. Originally considered a sub-family of Pteranodontidae, Nesov (1984) named the Azhdarchinae to include the pterosaurs Azhdarcho, Quetzalcoatlus, and Titanopteryx. They were among the last known surviving members of the pterosaurs, and were a rather successful group with a worldwide distribution. Previously it was thought that by the end of the Cretaceous, most pterosaur families except for the Azhdarchidae disappeared from the fossil record, but recent studies indicate a wealth of pterosaurian fauna, including pteranodontids, nyctosaurids, tapejarids and several indeterminate forms. In several analyses, some taxa such as Navajodactylus, Bakonydraco and Montanazhdarcho were moved from Azhdarchidae to other clades.
Azhdarcho is a genus of azhdarchid pterosaur from the late Cretaceous Period of the Bissekty Formation of Uzbekistan, as well as the Zhirkindek Formation of Kazakhstan and possibly also the Ialovachsk Formation of Tajikistan. It is known from fragmentary remains including the distinctive, elongated neck vertebrae that characterizes members of the family Azhdarchidae, a family that includes many giant pterosaurs such as Quetzalcoatlus. The name Azhdarcho comes from the Persian word azhdar (اژدر), a dragon-like creature in Persian mythology. The type species is Azhdarcho lancicollis. The specific epithet lancicollis is derived from the Latin words lancea and collum ("neck").
Asiamericana is a dubious genus of coelurosaur known only from isolated teeth found in the Bissekty Formation of Uzbekhistan. It was named to recognize the occurrence of similar fossil teeth in Central Asia and North America. These regions once formed a connected land mass, during the Cretaceous period.
Gobipteryx is a genus of prehistoric bird from the Campanian Age of the Late Cretaceous Period. It is not known to have any direct descendants. Like the rest of the enantiornithes clade, Gobipteryx is thought to have gone extinct near the end of the Cretaceous.
Abavornis is the name given to a genus of primitive birds from the Late Cretaceous, containing the single species A. bonaparti. It was probably a member of the Enantiornithes, but as it is only known from a single broken coracoid, which, however, looks typically enantiornithine, that assignment is tentative. The fossil is from Late Cretaceous Bissekty Formation in the Kyzylkum, Uzbekistan. Another partial coracoid is very similar and is referred to as Abavornis sp.; it might belong to A. bonaparti and if so show some features which are damaged in the holotype.
Nanantius is a genus of extinct enantiornithean avialan known from the Early Cretaceous of Australia.
Alexornis is a genus of enantiornithine birds from the Bocana Roja Formation of Baja California, Mexico. This geological formation has been dated to the late Cretaceous period, and more specifically to the Campanian age, about 73 mya. The type and only known species is Alexornis antecedens. Its name means "Alex's ancestral bird"; Alexornis from the given name of ornithologist Alexander Wetmore + Ancient Greek ornis, "bird", and antecedens, Latin for "going before" or "ancestral".
Incolornis is an extinct genus of basal birds from the Late Cretaceous. Remains have been found in the Bissekty Formation in Uzbekistan. It is only known from fragmentary coracoids. The systematic position of the genus is unclear; it might have been an enantiornithine bird.
Lenesornis is a genus of enantiornithine birds which lived during the Late Cretaceous about 90 Ma and is known from fossils found in the Bissekty Formation in the Kyzyl Kum, Uzbekistan.
Gurilynia is a genus of enantiornithine birds. One species is known, G. nessovi. It lived during the Maastrichtian stage of the Late Cretaceous period, between 70 and 66 mya. Gurilynia is known from fragmentary fossils found at the Gurilyn Tsav locality of the Nemegt Formation in south Gobi, Mongolia.
Ambiortus is an extinct genus of ornithuromorph dinosaurs. The only known species, Ambiortus dementjevi, lived sometime during the Barremian age between 136.4 and 125 million years ago in the Andaikhudag Formation of Mongolia. It was discovered by Yevgeny Kurochkin in 1982.
Catenoleimus is a prehistoric bird genus from the Late Cretaceous. It lived during the mid-late Turonian stage, around 90 million years ago. A single species Catenoleimus anachoretus has been described, and this is only known from one piece of coracoid, found in the Bissekty Formation of the Kyzyl Kum in present-day Uzbekistan.
Paleontology or palaeontology is the study of prehistoric life forms on Earth through the examination of plant and animal fossils. This includes the study of body fossils, tracks (ichnites), burrows, cast-off parts, fossilised feces (coprolites), palynomorphs and chemical residues. Because humans have encountered fossils for millennia, paleontology has a long history both before and after becoming formalized as a science. This article records significant discoveries and events related to paleontology that occurred or were published in the year 1993.
Paleontology or palaeontology is the study of prehistoric life forms on Earth through the examination of plant and animal fossils. This includes the study of body fossils, tracks (ichnites), burrows, cast-off parts, fossilised feces (coprolites), palynomorphs and chemical residues. Because humans have encountered fossils for millennia, paleontology has a long history both before and after becoming formalized as a science. This article records significant discoveries and events related to paleontology that occurred or were published in the year 1986.
The Bissekty Formation is a geologic formation and Lagerstätte which crops out in the Kyzyl Kum desert of Uzbekistan, and dates to the Late Cretaceous Period. Laid down in the mid to late Turonian, it is dated to about 92 to 90 Ma.
The Ialovachsk or Yalovach Formation is a geologic formation in Kyrgyzstan, Tajikistan and Uzbekistan dating to the Santonian age of the Cretaceous period.
Yevgeny Nikolayevich Kurochkin was a Russian paleornithologist at the Paleontological Institute of the Russian Academy of Sciences. He served as President of the Menzbier Ornithological Society.
