Troodontidae is a clade of bird-like theropod dinosaurs. During most of the 20th century, troodontid fossils were few and incomplete and they have therefore been allied, at various times, with many dinosaurian lineages. More recent fossil discoveries of complete and articulated specimens, have helped to increase understanding about this group. Anatomical studies, particularly studies of the most primitive troodontids, like Sinovenator, demonstrate striking anatomical similarities with Archaeopteryx and primitive dromaeosaurids, and demonstrate that they are relatives comprising a clade called Paraves.
Maniraptora is a clade of coelurosaurian dinosaurs which includes the birds and the non-avian dinosaurs that were more closely related to them than to Ornithomimus velox. It contains the major subgroups Avialae, Dromaeosauridae, Troodontidae, Oviraptorosauria, and Therizinosauria. Ornitholestes and the Alvarezsauroidea are also often included. Together with the next closest sister group, the Ornithomimosauria, Maniraptora comprises the more inclusive clade Maniraptoriformes. Maniraptorans first appear in the fossil record during the Jurassic Period, and survive today as living birds.
Darren William Naish is a British vertebrate palaeontologist, author and science communicator.
Magyarosaurus is a genus of dwarf sauropod dinosaur from late Cretaceous Period in Romania. It is one of the smallest-known adult sauropods, measuring only 6 m (20 ft) in length and 750–1,000 kg (1,650–2,200 lb) in body mass. The type and only certain species is Magyarosaurus dacus. It has been found to be a close relative of Rapetosaurus in the family Saltasauridae in the sauropod clade Titanosauria in a 2005 study.
Betasuchus is a genus of theropod dinosaur which lived during the Late Cretaceous Period. Betasuchus is, besides Orthomerus, the only dinosaur genus named from remains found in the Netherlands and the only non-avian theropod found in the Maastrichtian Beds.
Elopteryx is a genus of, perhaps troodontid, maniraptoran theropod dinosaur based on fragmentary fossils found in late Cretaceous Period rocks of Romania. The single species, Elopteryx nopcsai, is known only from very incomplete material, and therefore is considered a nomen dubium by most paleontologists.
Calamosaurus was a genus of small theropod dinosaur from the Barremian-age Lower Cretaceous Wessex Formation of the Isle of Wight, England. It is based on two cervical vertebrae, collected by Reverend William Fox.
Valdoraptor is a genus of theropod dinosaur from the Early Cretaceous. Its fossils were found in England. It is known only from bones of the feet. The holotype, BMNH R2559, was found near Cuckfield in layers of the Tunbridge Wells Sand Formation dating from the late Valanginian. The specimen is damaged lacking parts of the upper and lower ends. It has a conserved length of 215 millimetres (8.5 in) and an estimated length of 240 millimetres (9.4 in). This genus is paleontologically significant for being the first ornithomimosaur specimen known from England and represents the earliest record of ornithomimosaurs.
Variraptor is a genus of dromaeosaurid theropod dinosaur from the Late Cretaceous of France.
Heptasteornis is the name given to a potentially dubious genus of alvarezsaurid dinosaur from the Late Cretaceous. The type species is Heptasteornis andrewsi, described as a presumed gigantic prehistoric owl in 1975. It was previously included in Elopteryx nopcsai and indeed the holotypes of both were believed to be from the same individual as they were discovered, and initially were assigned the same specimen number. This appears to be in error however.
Hațeg Island was a large offshore island in the Tethys Sea which existed during the Late Cretaceous period, probably from the Cenomanian to the Maastrichtian ages. It was situated in an area corresponding to the region around modern-day Hațeg, Hunedoara County, Romania. Maastrichtian fossils of small-sized dinosaurs have been found in the island's rocks. It was formed mainly by tectonic uplift during the early Alpine orogeny, caused by the collision of the African and Eurasian plates towards the end of the Cretaceous. There is no real present-day analog, but overall, the island of Hainan is perhaps closest as regards climate, geology and topography, though still not a particularly good match. The vegetation, for example, was of course entirely distinct from today, as was the fauna.
Hatzegopteryx is a genus of azhdarchid pterosaur found in the late Maastrichtian deposits of the Densuş Ciula Formation, an outcropping in Transylvania, Romania. It is known only from the type species, Hatzegopteryx thambema, named by Buffetaut et al. in 2002 based on parts of the skull and humerus. Additional specimens, including a neck vertebra, were later placed in the genus, representing a range of sizes. The largest of these remains indicate it was among the biggest pterosaurs, with an estimated wingspan of 10 to 12 metres.
Argiles et Grès à Reptiles Formation also known as the Argiles Rutilantes Formation is an early Maastrichtian French geologic formation in the département of Var preserving the remains of several types of dinosaurs and other extinct organisms.
Gargantuavis is an extinct genus of large, primitive bird containing the single species Gargantuavis philoinos. It is the only member of the monotypic family Gargantuaviidae. Its fossils were discovered in several formations dating to 73.5 and 71.5 million years ago in what is now northern Spain, southern France, and Romania. Gargantuavis is the largest known bird of the Mesozoic, a size ranging between the cassowary and the ostrich, and a mass of 141 kg (311 lb) like modern ostriches, exemplifying the extinction of non-avian dinosaurs was not a necessary condition for the emergence of giant terrestrial birds. It was once thought to be closely related to modern birds, but the 2019 discovery of a pelvis from what was Hateg Island shows several primitive features.
The Densuș-Ciula Formation is a geological formation in Romania whose strata date back to the Late Cretaceous. It forms part of the Hațeg Island assemblage. Dinosaur remains are among the fossils that have been recovered from the formation. It is divided up into three members, the lower member is noted for high content of volcanogenic material and is poorly fossiliferous. While the Middle member consists of silty mudstones, sandstones and conglomerates containing volcanogenic clasts and is richly fossiliferous, while the upper member consists of matrix supported red conglomerates and is poorly fossiliferous.
The Sânpetru Formation is an early Maastrichtian geologic formation. Dinosaur remains are among the fossils that have been recovered from the formation. It is located in Romania, near Sânpetru village, part of Sântămăria-Orlea commune. It forms a component of the Hațeg Island fauna.
Paludititan is a genus of titanosaurian sauropod dinosaur which lived in the area of present Romania during the Late Cretaceous. It existed in the island ecosystem known as Hațeg Island.
Balaur is a genus of theropod dinosaur from the late Cretaceous period, in what is now Romania. It is the type species of the monotypic genus Balaur, after the balaur, a dragon of Romanian folklore. The specific name bondoc means "stocky", so Balaur bondoc means "stocky dragon" in Romanian. This name refers to the greater musculature that Balaur had compared to its relatives. The genus, which was first described by scientists in August 2010, is known from two partial skeletons.
This timeline of troodontid research is a chronological listing of events in the history of paleontology focused on the troodontids, a group of bird-like theropod dinosaurs including animals like Troodon. Troodontid remains were among the first dinosaur fossils to be reported from North America after paleontologists began performing research on the continent, specifically the genus Troodon itself. Since the type specimen of this genus was only a tooth and Troodon teeth are unusually similar to those of the unrelated thick-headed pachycephalosaurs, Troodon and its relatives would be embroiled in taxonomic confusion for over a century. Troodon was finally recognized as distinct from the pachycephalosaurs by Phil Currie in 1987. By that time many other species now recognized as troodontid had been discovered but had been classified in the family Saurornithoididae. Since these families were the same but the Troodontidae named first, it carries scientific legitimacy.
