Ajancingenia

Ajancingenia
Temporal range: Late Cretaceous, 70 Ma
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Skeletal diagram showing known elements
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Order: Saurischia
Suborder: Theropoda
Family: †Oviraptoridae
Subfamily: †Ingeniinae
Genus: †Ajancingenia
Easter, 2013
Type species
†Ajancingenia yanshini
Barsbold, 1981
Species

†Ajancingenia yanshini
(Barsbold, 1981)

Synonyms

Ingenia yanshini Barsbold, 1981 (preoccupied)

Ajancingenia is a genus of oviraptorid theropod dinosaurs, with one known species, Ajancingenia yanshini. Fossils have been found in several Late Cretaceous-age formations (approximately 70 million years ago) of Mongolia, most prominently in the Khermin Tsav beds of the Barun Goyot Formation. Ajancingenia is known from several specimens, which include the arms, legs, pelvis, shoulder girdle, and partial skull, and a few vertebrae. Some material referred to as Ajancingenia comes from younger formations, but the identification of some of these specimens is questionable.[1]

History of discovery

Skeleton of an undescribed specimen

Ajancingenia was first described and named by Rinchen Barsbold in 1981 and the type species is Ingenia yanshini. The name "Ingenia" derives from the Ingen Khoboor Depression of Bayankhongor Province, Mongolia, from whence it was collected, while the specific name yanshini was chosen in honour of academician Aleksandr Leonidovich Yanshin (1911–1999), who was adviser and mentor to Rinchen Barsbold during his time at the Paleontological Institute in St. Petersburg, Russia.[2]

The generic name Ingenia was preoccupied by the generic name of Ingenia mirabilis (Gerlach, 1957), a tripyloidid nematode. Thus, an alternative generic name, Ajancingenia, was proposed by Jesse Easter in 2013. The replacement generic name is derived also from ajanc (аянч)(a traveler in Mongolian), as a Western allusion of sticking one’s thumb out for hitchhiking, in reference to the first manual ungual of Ajancingenia which is twice as large as the second.[1]

Classification

Ajancingenia yanshini belongs to the oviraptorids, as distinguished by a pubis with a forward-curving shaft (among other features), and by the unique shape of the lower jaw with a strongly S-curved jaw margin, short snout, and rounded, fused cranial bones. Some material includes paired sternal plates fused along the midline and bearing a short carina.

It is distinguished from all other oviraptorids by manual digit I subequal in length to digit II, and from all other oviraptorids except Nemegtomaia barsboldi by manual ungual I more than 100% larger than ungual II.[1]

Reconstruction of a male displaying to a female

The cladogram below follows an analysis by Fanti et al., 2012.[3]

Oviraptoridae


Oviraptor


unnamed


Rinchenia

Citipati



unnamed


Khaan


unnamed


Conchoraptor


unnamed


Machairasaurus


unnamed


"Ingenia" (=Ajancingenia)


unnamed


Nemegtomaia

Heyuannia








See also

References

  1. 1 2 3 Easter, J. (2013). "A new name for the oviraptorid dinosaur "Ingenia" yanshini (Barsbold, 1981; preoccupied by Gerlach, 1957)". Zootaxa. 3737 (2): 184–190. doi:10.11646/zootaxa.3737.2.6.
  2. ↑ Barsbold, R. (1981). "Bezzubye khishchnye dinozavry Mongolii." [Toothless carnivorous dinosaurs of Mongolia.]. Trudy -- Sovmestnaya Sovetsko-Mongol'skaya Paleontologicheskaya Ekspeditsiya, 15: 28-39, 124. [in Russian, w/ English summary].
  3. ↑ Fanti F, Currie PJ, Badamgarav D (2012). "New Specimens of Nemegtomaia from the Baruungoyot and Nemegt Formations (Late Cretaceous) of Mongolia." PLoS ONE, 7(2): e31330. doi:10.1371/journal.pone.0031330
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