''Asiamericana'' (AY-zha-MER-i-KAHN-a – (

Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...

: ''Asia'' meaning

Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an area ...

and

New Latin New Latin (also called Neo-Latin or Modern Latin) is the revival of Literary Latin used in original, scholarly, and scientific works since about 1500. Modern scholarly and technical nomenclature, such as in zoological and botanical taxonomy ...

''Americas'' meaning

Americas The Americas, which are sometimes collectively called America, are a landmass comprising the totality of North and South America. The Americas make up most of the land in Earth's Western Hemisphere and comprise the New World. Along with th ...

) is a

dubious Doubt is a mental state in which the mind remains suspended between two or more contradictory propositions, unable to be certain of any of them. Doubt on an emotional level is indecision between belief and disbelief. It may involve uncertainty, ...

dinosaur

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

known only from isolated teeth. It was named to recognize the occurrence of similar fossil teeth in

Central Asia Central Asia, also known as Middle Asia, is a subregion, region of Asia that stretches from the Caspian Sea in the west to western China and Mongolia in the east, and from Afghanistan and Iran in the south to Russia in the north. It includes t ...

and

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

. These regions once formed a connected land mass, during the

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of th ...

period and were referred to as

Asiamerica Asiamerica was a supercontinent formed from the Laurasian landmass and separated by shallow continental seas from Eurasia to the West and eastern North America to the East. This region incorporated what is now politically China, Mongolia, wester ...

. The teeth were discovered by L. A. Nesov in 1995. The findings were based on three teeth found in the central

Kyzylkum desert The Kyzylkum Desert ( uz, Qizilqum, Қизилқум, قىزىلقۇم; kk, Қызылқұм, Qyzylqūm, قىزىلقۇم) is the 15th largest desert in the world. Its name means ''Red Sand'' in Turkic languages. It is located in Central Asia, i ...

Uzbekistan Uzbekistan (, ; uz, Ozbekiston, italic=yes / , ; russian: Узбекистан), officially the Republic of Uzbekistan ( uz, Ozbekiston Respublikasi, italic=yes / ; russian: Республика Узбекистан), is a doubly landlocked cou ...

, in deposits of the

Bissekty Formation The Bissekty Formation (sometimes referred to as Bissekt) is a geologic formation and Lagerstätte which crops out in the Kyzyl Kum desert of Uzbekistan, and dates to the Late Cretaceous Period. Laid down in the mid to late Turonian, it is dated ...

, dated to the mid-late

Turonian The Turonian is, in the ICS' geologic timescale, the second age in the Late Cretaceous Epoch, or a stage in the Upper Cretaceous Series. It spans the time between 93.9 ± 0.8 Ma and 89.8 ± 1 Ma (million years ago). The Turonian is preceded by t ...

age of the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', the ...

, about 90 million years ago. They are comparable to other teeth found in

Kazakhstan Kazakhstan, officially the Republic of Kazakhstan, is a transcontinental country located mainly in Central Asia and partly in Eastern Europe. It borders Russia to the north and west, China to the east, Kyrgyzstan to the southeast, Uzbeki ...

and North America, which have been illustrated but not formally described. The

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...

is ''A. asiatica''. The teeth themselves are straight, lack a constriction at the base, and lack serrations.Nessov, 1995. Dinozavri severnoi Yevrasii: Novye dannye o sostave kompleksov, ekologii i paleobiogeografii inosaurs 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. n Russian with short English, German, and French abstracts

Classification

In his initial description of the unusual teeth, Nesov speculated that they may belong to either saurodont

fish Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of li ...

or to

spinosaurid The Spinosauridae (or spinosaurids) are a clade or family of tetanuran theropod dinosaurs comprising ten to seventeen known genera. They came into prominence during the Cretaceous period. Spinosaurid fossils have been recovered worldwide, includi ...

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...

s. He later changed his opinion, deciding that they definitely represented theropod remains,Nessov, L.A. (1997). ''Cretaceous nonmarine vertebrates of northern Eurasia.'' Saint Petersburg: University of Saint Petersburg Institute of Earth Crust, 218 pp. n Russian and this opinion was followed by most later researchers who excluded them from reviews of spinosaurid teeth for this reason.Buffetaut, Suteethorn, Tong and Amiot (2008). "An Early Cretaceous spinosaurid theropod from southern China." ''Geological Magazine'', 145(5): 745–748. However, in 2013 a study assumed that the teeth were identical to those of the possibly

dromaeosaurid Dromaeosauridae () is a family of feathered theropod dinosaurs. They were generally small to medium-sized feathered carnivores that flourished in the Cretaceous Period. The name Dromaeosauridae means 'running lizards', from Greek ('), meaning ...

Richardoestesia ''Richardoestesia'' is a morphogenus of theropod dinosaur teeth, originally described from the Late Cretaceous of what is now North America. It currently contains two species, ''R. gilmorei'' and ''R. isosceles''. It has been used as a morphotax ...

isosceles'', and renamed the species into ''Richardoestesia asiatica''. A subsequent study confirmed this in 2019.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

References

{{Taxonbar, from=Q1425817 Prehistoric coelurosaurs Late Cretaceous dinosaurs of Asia Fossil taxa described in 1995