Archaeopteryx, sometimes referred to by its German name, "Urvogel" is a genus of bird-like dinosaurs. The name derives from the ancient Greek ἀρχαῖος (archaīos), meaning "ancient", and πτέρυξ (ptéryx), meaning "feather" or "wing". Between the late 19th century and the early 21st century, Archaeopteryx was generally accepted by palaeontologists and popular reference books as the oldest known bird. Older potential avialans have since been identified, including Anchiornis, Xiaotingia, and Aurornis.
Caudipteryx is a genus of small oviraptorosaur dinosaurs that lived in Asia during the Early Cretaceous, around 124.6 million years ago. They were feathered and extremely birdlike in their overall appearance, to the point that some paleontologists suggested it was a bird. Two species have been described: C. zoui, in 1998, and C. dongi, in 2000.
Microraptor is a genus of small, four-winged dromaeosaurid dinosaurs. Numerous well-preserved fossil specimens have been recovered from Liaoning, China. They date from the early Cretaceous Jiufotang Formation, 125 to 120 million years ago. Three species have been named, though further study has suggested that all of them represent variation in a single species, which is properly called M. zhaoianus. Cryptovolans, initially described as another four-winged dinosaur, is usually considered to be a synonym of Microraptor.
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.
Scansoriopterygidae is an extinct family of climbing and gliding maniraptoran dinosaurs. Scansoriopterygids are known from five well-preserved fossils, representing four species, unearthed in the Tiaojishan Formation fossil beds of Liaoning and Hebei, China.
Longisquama is a genus of extinct reptile. There is only one species, Longisquama insignis, known from a poorly preserved skeleton and several incomplete fossil impressions from the Middle to Late Triassic Madygen Formation in Kyrgyzstan. It is known from the type fossil specimen, slab and counterslab and five referred specimens of possible integumentary appendages. All specimens are in the collection of the Paleontological Institute of the Russian Academy of Sciences in Moscow.
Jeholornis is a genus of avialan dinosaurs 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.
Sordes was a small pterosaur from the late Jurassic (Oxfordian/Kimmeridgian) Karabastau Svita of Kazakhstan.
Nanantius is a genus of extinct enantiornithean avialan known from the Early Cretaceous of Australia.
Paraves are a widespread group of theropod dinosaurs that originated in the Middle Jurassic period. In addition to the extinct dromaeosaurids, troodontids, anchiornithids, and possibly the scansoriopterygids, the group also contains the avialans, which include diverse extinct taxa as well as the over 10,000 species of living birds. Basal members of Paraves are well known for the possession of an enlarged claw on the second digit of the foot, which was held off the ground when walking in some species. A number of differing scientific interpretations of the relationships between paravian taxa exist. New fossil discoveries and analyses make the classification of Paraves an active subject of research.
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.
Archaeorhynchus is a genus of beaked avialan stem-birds from the early Cretaceous period. A fossil of its only known species, Archaeorhynchus spathula, was first reported in 2005 by Zhou & Zhang to have been found in Yixian Formation rocks at Yixian, Liaoning province, China, showing a well-preserved and essentially complete skeleton. Two more complete specimens were found in Lower Cretaceous deposits of Jianchang, Liaoning, northeastern China, preserving new anatomical information. These deposits are 120 million years old, whereas the original specimen was 125 million years old, meaning the age range for this species is 125-120Ma.
Karatausuchus is an extinct genus of atoposaurid crocodylomorph. It is known from a single specimen discovered in the Late Jurassic Karabastau Svita from the vicinity of Mikhailovka in the Karatau Mountains of southern Kazakhstan. The type specimen is PIN 25858/1, a complete but poorly preserved juvenile skeleton with some possible soft tissue preservation. It is notable for having over 90 teeth, but its other anatomical details are difficult to discern. The length of this individual is estimated at 160 millimetres (6.3 in). Karatausuchus was described in 1976 by Mikhail Efimov, and the type species is K. sharovi.
Xiaotingia is a genus of anchiornithid theropod dinosaur from Middle Jurassic or early Late Jurassic deposits of western Liaoning, China, containing a single species, Xiaotingia zhengi.
The Karabastau Formation is a geological formation and lagerstätte in the Karatau Mountains of southern Kazakhstan whose strata date to the Middle to Late Jurassic. It is an important locality for insect fossils that has been studied since the early 20th century, alongside the rarer remains of vertebrates, including pterosaurs, salamanders, lizards and crocodiles.
Euornithes is a natural group which includes the most recent common ancestor of all avialans closer to modern birds than to Sinornis.
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.
Anchiornithidae is a family of small paravian dinosaurs. Anchiornithids have been classified at varying positions in the paravian tree, with some scientists classifying them as a distinct family, a basal subfamily of Troodontidae, members of Archaeopterygidae, or an assemblage of dinosaurs that are an evolutionary grade within Avialae or Paraves.
Aleksandr Sergeevich Rautian is a Russian paleontologist working at the Paleontological Institute of the Russian Academy of Sciences in Moscow, Russia.
