Open Paleo

Oksoko

Funston et al., 2020 Oak-soak-oh

From Öksökö, a mythical two-headed bird in Yakut (Sakha) folklore of Siberia

72.2–66.0 million years ago Maastrichtian, Late Cretaceous
Late Cretaceous stages

Oksoko is a genus of oviraptorid dinosaur from the Late Cretaceous Nemegt Formation of Ömnögovi Province, Mongolia. The type and only species is Oksoko avarsan. It is notable for having only two functional fingers, having lost the third manual digit, suggesting a trend toward digit reduction within oviraptorosaurs.

Diagnosis

  1. Apically thickened, dome-shaped cranial crest composed equally of nasals and frontals
  2. Nasal recesses housed in depression
  3. Postorbital with dorsally directed frontal process
  4. Cervical vertebrae with large epipophyses
  5. Functionally didactyl manus
  6. Accessory ridge of brevis fossa of ilium
  7. Anteriorly curving pubis
  8. Large proximodorsal process of distal tarsal IV

Species

Oksoko avarsan Funston et al., 2020

Type species

From the Mongolian word 'avarsan' meaning 'rescued', given that specimens of the genus were redeemed from fossil poachers.

Holotype
MPC-D 102/110 , Paleontological Center, Mongolian Academy of Sciences
Material
Block assemblage of three individuals: skulls, cervical vertebrae, pelvis, hindlimbs, caudal vertebrae, forelimb material.
Horizon
Nemegt Formation, Maastrichtian, Late Cretaceous , 72.2–66.0 million years ago
Locality
Mongolia The holotype was poached and confiscated before leaving Mongolia, and Funston and colleagues record that its exact provenance within the Nemegt Formation is unknown. The Bügiin Tsav and Guriliin Tsav sites they name belong to the lawfully collected referred specimens.

Notable specimens

  • MPC-D 102/12

    Paleontological Center, Mongolian Academy of Sciences Found 1998 ontogeny

    The only known adult specimen of Oksoko, at least 5 years old with an estimated body mass of 74 kg, contrasting with the juvenile holotype individuals and showing the limb bones become more robust in adults.

    Funston et al. (2020)

  • MPC-D 100/33

    Paleontological Center, Mongolian Academy of Sciences Found 1974 by Soviet-Mongolian Palaeontological Expedition

    The first specimen of Oksoko, a partial subadult postcranial skeleton, long referred to as a paratype of Heyuannia but sharing traits with Oksoko including a reduced third metacarpal.

    Funston et al. (2020)

References

  1. Funston, G. F.; Chinzorig, T.; Tsogtbaatar, K.; Kobayashi, Y.; Sullivan, C.; Currie, P. J. (2020). A new two-fingered dinosaur sheds light on the radiation of Oviraptorosauria. Royal Society Open Science 7(10): 201184. The Royal Society. doi:10.1098/rsos.201184 funston2020a
  2. Paul, G. S. (2024). The Princeton Field Guide to Predatory Dinosaurs. Princeton University Press.

    Source of the appearance features.

    paul2024b