''Oksoko'' (''Oak-soak-oh''; from '' Öksökö'', a mythical bird of Yakut folklore) is a genus of

oviraptorid Oviraptoridae is a group of bird-like, herbivorous and omnivorous maniraptoran dinosaurs. Oviraptorids are characterized by their toothless, parrot-like beaks and, in some cases, elaborate crests. They were generally small, measuring between one ...

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 ...

from 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 ...

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 ...

, that lived in what is now the

Nemegt Formation The Nemegt Formation (also known as Nemegtskaya Svita) is a geological formation in the Gobi Desert of Mongolia, dating to the Late Cretaceous. The formation consists of river channel sediments and contains fossils of fish, turtles, crocodilian ...

Mongolia Mongolia; Mongolian script: , , ; lit. "Mongol Nation" or "State of Mongolia" () is a landlocked country in East Asia, bordered by Russia to the north and China to the south. It covers an area of , with a population of just 3.3 million, ...

. It includes 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 ...

''Oksoko avarsan''.

History of discovery

The first

specimen Specimen may refer to: Science and technology * Sample (material), a limited quantity of something which is intended to be similar to and represent a larger amount * Biological specimen or biospecimen, an organic specimen held by a biorepository ...

of ''Oksoko'', MPC-D 100/33, was discovered in 1974 by the Soviet-Mongolian Palaeontological Expedition at the Bügiin Tsav locality in the

. It is represented by a partial subadult postcranial skeleton. The

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several ...

specimen is a block of an assemblage of three individuals buried in life positions that has been labelled as MPC-D 102/110. The first individual, subcatalogued as MPC-D 102/110a, is a partial skeleton of a juvenile preserving the

skull The skull is a bone protective cavity for the brain. The skull is composed of four types of bone i.e., cranial bones, facial bones, ear ossicles and hyoid bone. However two parts are more prominent: the cranium and the mandible. In humans, the ...

cervical vertebrae In tetrapods, cervical vertebrae (singular: vertebra) are the vertebrae of the neck, immediately below the skull. Truncal vertebrae (divided into thoracic and lumbar vertebrae in mammals) lie caudal (toward the tail) of cervical vertebrae. In ...

pelvis The pelvis (plural pelves or pelvises) is the lower part of the trunk, between the abdomen and the thighs (sometimes also called pelvic region), together with its embedded skeleton (sometimes also called bony pelvis, or pelvic skeleton). The ...

, hindlimbs, and

caudal vertebrae The spinal column, a defining synapomorphy shared by nearly all vertebrates,Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characteristic ...

. Another specimen in this block is represented by MPC-D 102/110b, a large quadrate and quadratojugal. The third specimen in this assemblage is MPC-D 102/110c, a juvenile postcranial skeleton. This block was in 2006 confiscated from poachers by the

General Intelligence Agency of Mongolia The General Intelligence Agency of Mongolia (GIA; Mongolian language: ''Тагнуулын ерөнхий газар'') is the intelligence agency of the Mongolian government, under the direct control of the Prime Minister of Mongolia. Its headqu ...

along with a fourth specimen, MPC-D 102/11, representing a partial juvenile skeleton preserving the skull. They were later returned to the Mongolian Palaeontological Center on December 14 during the same year, where they were posteriorly prepared by professionals. Both specimens share taphonomical traits, such as the death pose,

sediments Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, sand a ...

and preservation state, which may suggest that MPC-D 102/11 is part of the holotype block assemblage. Oksoko MPC-D 102 110 skull

Though the exact localities of these specimens are currently unknown due to their theft, the color of their sediments and geochemical analyses confirm their provenance from the Nemegt Formation. Another, and isolated specimen was collected in 1998 at the Guriliin Tsav locality by a joint expedition from the Hayashibara Museum of Natural Sciences and the Mongolian Palaeontological Center. It was catalogued as MPC-D 102/12 and represents postcranial skeleton of an adult individual. All of the specimens were later assigned to the new

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 ...

and

''Oksoko avarsan'', named in

2020 2020 was heavily defined by the COVID-19 pandemic, which led to global Social impact of the COVID-19 pandemic, social and Economic impact of the COVID-19 pandemic, economic disruption, mass cancellations and postponements of events, COVID- ...

by the

paleontologist Paleontology (), also spelled palaeontology or palæontology, is the scientific study of life that existed prior to, and sometimes including, the start of the Holocene epoch (roughly 11,700 years before present). It includes the study of fossi ...

s Gregory F. Funston, Tsogtbaatar Chinzorig, Khishigjav Tsogtbaatar,

Yoshitsugu Kobayashi {{Short pages monitor