1: Suprageneric Taxa
Caenagnathasia Currie, Godfrey, and Nessov, 1994 ~ (nomen validum)
Microvenator Ostrom, 1970 ~ (nomen validum)
Three theropod specimens were found in the Judith River Formation (then known as the Belly River (later as the Oldman)) of Alberta, Canada, in 1924. The first was Chirostenotes pergracilis ("very slender narrow hands"), and was based on a pair of hands, one only partial; the morphology of the hands were similar only at the time to Ornitholestes ("bird thief"), which considering its similarity to Coelurus ("hollow tail") had been named a member of Coeluridae (Osborn, 1903). (A recent find suggests that the hand of Ornitholestes, once considered Coelurus, does in fact belong to the latter.) The hands were referred to that genus and the Coeluridae.
The second specimen was named Macrophalangia canadensis ("large digits from Canada") by Sternberg in 1932 and was based on a metatarsus with a complete set of pedal digits and unguals; the metatarsus possessed a pinched third metatarsal, at the time known only in ornithomimids, and so was referred to the Ornithomimidae along with Oviraptor.
The third was originally referred along with the pair of hands to C. pergracilis (Gilmore, 1924), and consisted of a pair of dentaries, opposites, that would later be given the name Ricardoestesia ("for Richard Estes"). It was questioned at the time whether any of the specimens from the Judith River locality called "Steveville" belonged to the same or different species, but this was not followed up as there were no comparable bones.
Parks, in 1933, described a metatarsus as Ornithomimus elegans ("delicate bird mimic"), a small animal with a pinched third metatarsal, at the time, a character defining ornithomimids.
Barnum Brown, in 1932, collected a skeleton of a small theropod in the Cloverly Formation of Wyoming, USA, and labelled it "Megadontosaurus"; he neither described it, published the name in any form, nor refered to it since. Also refered to the type were teeth of the dromaeosaurid form, suggesting to Brown a large skulled animal.
Additionally, Sternberg (1940) named a nearly complete lower jaw with toothless margins as Caenagnathus collinsi ("Collins' recent jaw"); the form of the jaws, elongate and toothless, suggested to Sternberg that the jaws, over 9 inches long, were avian, and in accordance to the custom of bird taxa, named the Caenagnathidae and Caenagnathiformes to illustrate its difference from all other birds. He also conceded its possible cursoriality.
Whetmore (1960) examined Caenagnathus and noted numerous reptilian characters, as if to decide that the Linnean "Class" Aves was different enough from the "Class" Reptilia that one could not encompass the other; Romer (1966) referred Caenganathus to the Dinosauria and further to the Coelurosauria. The Infraorder Coelurosauria contained, by that time, the Ornithomimidae and Coeluridae.
Cracraft, an ornithologist (not decreasing his knowledge and skill in these matters) also examined Caenagnathus, and in 1971 concluded that it was, in fact, a bird, and considered that a new specimen from the Judith River, a small articular region more robust but smaller than the type species, were a new species, C. sternbergi ("Sternberg's recent jaw").
Ostrom (1970) described the skeleton collected by Brown as Microvenator celer ("swift little hunter") and opined that it was a juvenile, but also had many mature features; he refered the teeth to Dromaeosaurus, in the same formation.
In the 1970's, the Mongolian government allowed first the Russian, and then the Polish, governments into the country to tackle what Granger and Andrews had found at various sites in the northern Gobi Desert, a treasure trove ripe for the picking. Mongolia was the new Xanadu, and the name would even apply to a locality during the MAE (Mongolian Academy of Sciences and AMNH Expeditions) of the 1990's. Localities like Bayn Dzak (Shabarak Usu, also popularly, the Flaming Cliffs), Khermeen-Tsav, Bugin-Tsav, and more. The expeditions succeeded in bringing numerous fantastic specimens (juveniles, nests, giants, tanks, and bizarre creatures the like of which had never been seen). The descriptions would be published for two decades, between 1976 and the late 1980's.
Barsbold, in 1976, published two papers that detailed that old dinosaur, Oviraptor. Barsbold, meanwhile, tackled the phylogenetic angle and in the first paper, named the Oviraptoridae to include Oviraptor and not Ornithomimidae. He also named the Ornithomimosauria to include both groups; the differentiation was based on manual and skull characters. In the next paper, he diagnosed the Oviraptoridae officially.
Getting into the piles of material available to study, Barsbold (1981) described Ingenia yanshini ("Yanshin's from Ingen-Khobur") from specimens originally ascribed to Oviraptor. He also separated the Oviraptoridae into two, one group for each taxon, each primarily diagnosed by the hand: the Ingeniinae for a large thumb digit and shorter second finger, and the Oviraptorinae for the opposite, though the thumb claw in both is still larger than all the rest. He would later, in 1983, further this discussion with more material and an analysis of much of the new Mongolian material, from Oviraptor to Tarbosaurus (Tyrannosaurus).
Osmólska (1981) described a foot, and referred a pair of hands and another foot (from two specimens) from Mongolia, as Elmisaurus rarus ("rare foot lizard"), and erected the taxon Elmisauridae to include it; she also found similarities between Chirostenotes' hands and Macrophalangia's foot with Elmisaurus, and referred both to the Elmisauridae; she also suggested that Chirostenotes and Macrophalangia were congeneric, as based on shared characters with one animal, even if it was Mongolian. She did not refer the Elmisauridae to any higher taxon, and labeled it Theropoda incertae sedis.
1985 brought and new taxon: Oviraptor mongoliensis ("egg snatcher from Mongolia"), and in 1986, Conchoraptor gracilis ("gracile shell snatcher") and both described by Barsbold. The first was the smallest yet oviraptorid and was a redescription of material that had been originally referred to Oviraptor and Ingenia, and the other was a uniquely-crested animal that instantly reminded Barsbold of Oviraptor.
In 1988, Currie and Russell described a skeleton that had been held in storage for decades as Chirostenotes as based on manual and pedal material, and subsequently referred Macrophalangia to Chirostenotes as a junior synonym.
Currie published, in 1988, a description of more material of Elmisaurus, this time specimens from Alberta, Canada; the similarity of these metatarsals to the holotype was shown as greater than that of the new bones to Chirostenotes, which was in the same stratigraphic and geological level. The similarity of these bones to Ornithomimus elegans was noted, and O. elegans was referred to Elmisaurus as E. elegans ("delicate foot lizard").
Paul (1988) described the Oviraptoridae and refered Ingenia to Oviraptor as O. yanshini, based largely on the similarities of their skulls, which are remarkably alike. He also refered Elmisaurus to Chirostenotes, based on the hands and feet. In addition to the standard oviraptorids, Paul suggested that Microvenator was an oviraptorid, and the most basal one due to numerous synapomorphies, including a near abscence of neural spines on the cervical vertebrae.
The latest analyses have suggested that (in 1990 and 1997) that both the Oviraptorinae and Ingeniinae be kept as valid taxa (Barsbold, Maryanska, and Osmólska 1990), and be dropped (Barsbold, 1997); the Caenagnathidae was also referred to the Oviraptorosauria (Barsbold, Maryanska, and Osmólska 1990). The main argument is that a monotypic suprageneric taxon is invalid, in that there is no way to show that, above a genus, this taxon can be compared to anything else when the genus itself will do.
In 1990, Currie, Rigby, and Sloan named Ricardoestesia, and validated it as not being Chirostenotes, but rather a tooth-bearing theropod with similarities to dromaeosaurids and tyrannosaurids in the structure of the interdental plates and teeth.
Currie, Godfrey, and Nessov (1993) described Caenagnathasia martinsoni ("Martinson's recent jaw of Asia") from incomplete dentaries in the Turonian of Uzbekistan; it's significance as the most primitive oviraptorosaur does not go unnoticed. They also indicated a partial jaw from the Hell Creek Formation and provisionally called it C. sp., as they could not accurately determine under the present studies if it was a new species, or referable to an existing one. It could be Elmisaurus, which is more robust than Chirostenotes, though the North American species is more gracile than the Mongolian one. Mention was also made of fused dentaries where the tip was shaped like a spade.
1997 brought Sues' description of a second skeleton of Chirostenotes, this one including a maxillary fragment; the bone was edentulous and showed no evidence of tooth alveoli, unlike in Caenagnathasia's dentaries, and were strongly convexly curved; Sues compared the arc of the maxilla to the mandible of Caenagnathus, and the two compared in size and shape. Sues subsequently referred Caenagnathus, the younger taxon, to Chirostenotes. The Caenagnathidae was considered a valid taxon, as even when the type species was subsumed, the name still had priority by age over the Elmisauridae, which Chirostenotes was referred to. Elmisauridae was discarded, and Elmisaurus elegans was referred to Chirostenotes pergracilis, along with Caenagnathus collinsi; Caenagnathus sternbergi was renamed Chirostenotes sternbergi.
Barsbold (1997) mentioned the name Rinchenia would replace Oviraptor mongoliensis; he has not so far designated a type specimen, or offered a description, making it a nomen nudum.
In 1998, Makovicky and Sues redescribed the type specimen of Microvenator celer and placed the animal as either the closest sister-group to the Oviraptorosauria, or within the Oviraptorosauria as posibly its most basal member.
Sereno (1999) described the Oviraptoroidea, as Caenagnathidae, Oviraptoridae, their most recent common ancestor, and all descendants of that ancestor. However, as pointed out by Olshevsky, this name is invalid except as a junior synonym because, in accordance with the ICZN, the name would have to comprise the oldest included family-level taxon, in this case Caenagnathidae, rather than the oldest generic-level taxon, as in Oviraptor, thus the name will be changed to "Caenagnathoidea" (Sereno, pers. comm. to Olshevsky, 1999).
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