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Asiamericana

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Asiamericana
Temporal range: Late Cretaceous, 90 Ma
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Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Saurischia
Clade: Theropoda
Clade: Coelurosauria
Genus: †Asiamericana
Nesov, 1995
Species:
†A. asiatica
Binomial name
†Asiamericana asiatica
Nesov, 1995
Synonyms

Asiamericana (AY-zha-MER-i-KAHN-a – (Greek: Asia meaning Asia and Neo-Latin Americas meaning Americas) is a dubious genus of coelurosaur known only from isolated teeth found in the Bissekty Formation of Kazakhstan. 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 and were referred to as Asiamerica.

Discovery and naming

The holotype teeth were discovered during the Uzbek-Russian-British-American-Canadian (URBAC) expedition by Lev Alexandrovich Nessov between 1974 and 1985 and were first described by Nesov (1985).[1] The type species is A. asiatica, which was named and described by Nesov (1995).[2]

The holotype of A. asiatica is CCMGE 460/12457,[2] and two other teeth (ZIN PH 1110/ 16 and (ZIN PH 1129/16) are also known.[3]

Description

The teeth themselves are straight, lack a constriction at the base, and lack serrations.[2]

Classification

In his initial description of the unusual teeth, Nesov speculated that they may belong to either saurodont fish or to spinosaurid dinosaurs.[2] He later changed his opinion, deciding that they definitely represented theropod remains,[4] and this opinion was followed by most later researchers who excluded them from reviews of spinosaurid teeth for this reason.[5]

However, in 2013 a study assumed that the teeth were identical to those of the possibly dromaeosaurid Richardoestesia isosceles, and renamed the species into Richardoestesia asiatica.[6] A subsequent study confirmed this in 2019.[3]

References

  1. ^ L. A. Nessov. (1985). Rare bony fishes, terrestrial lizards, and mammals in the estuarine and coastal lowland zone of the Kyzyl-Kum Cretaceous. Yearbook of the All-Union Paleontological Association 28:199-219 [in Russian]
  2. ^ a b c d Nessov, L. A. (1995). Dinozavri severnoi Yevrasii: Novye dannye o sostave kompleksov, ekologii i paleobiogeografii [Dinosaurs of Northern Eurasia: new data about assemblages, ecology and paleobiogeography], Scientific Research Institute of the Earth's Crust, St. Petersburg State University, St. Petersburg, Russia: 156 pp. + 14 pl. [in Russian with short English, German, and French abstracts].
  3. ^ a b Alexander Averianov & Hans-Dieter Sues. (2019). "Morphometric analysis of the teeth and taxonomy of the enigmatic theropod Richardoestesia from the Upper Cretaceous of Uzbekistan". Journal of Vertebrate Paleontology: e1614941
  4. ^ Nessov, L.A. (1997). Cretaceous nonmarine vertebrates of northern Eurasia. Saint Petersburg: University of Saint Petersburg Institute of Earth Crust, 218 pp. [in Russian].
  5. ^ Buffetaut, Suteethorn, Tong and Amiot (2008). "An Early Cretaceous spinosaurid theropod from southern China." Geological Magazine, 145(5): 745–748.
  6. ^ Sues H.D. and Averianov, A. (2013). "Enigmatic teeth of small theropod dinosaurs from the Upper Cretaceous (Cenomanian–Turonian) of Uzbekistan". Canadian Journal of Earth Sciences. 50: 306-314
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