Oviraptorosaur Dinosaur Discovered in Mongolia

Out of the famous fossil bearing Nemegt Formation has come yet another species of Oviraptorosaur, and this one is unlike any ever discovered in the past.

My own reconstruction of Oksoko avarsan, done using a skeletal image as reference.

Called “Oksoko avarsan“, three juvenile specimens of this dinosaur were discovered with remarkably complete skeletons, having died together in the Maastrichtian stage of the Late Cretaceous epoch, the very last stage before the reign of the dinosaurs ended. Upon inspection of such a rare, spectacular find, paleontologists immediately took note of the most puzzling and interesting feature of Oksoko: the two fingered hands. No known oviraptorosaur besides Oksoko evolved this feature. The fact that oviraptorosaurs like Oksoko could evolve such adaptations to better suit their specific lifestyles suggests that oviraptorosaurs were on track to diversifying into many different forms before the K/T Extinction Event descended upon the Earth, wiping non-avian dinosaurs off the map entirely.

Skeletons of Oksoko avarsan in ventral view; colors distinguish different individuals; the holotype individual is in blue. Image credit: Funston et al

Oksoko would have been around 6 and a half feet long, and displayed many typical oviraptorosaurid characteristics such as powerful legs adapted for running in the open desert, a tall ornamental crest mounted on its skull, most likely for sexual display, a sharp toothless beak, and a fantastic coat of feathers. This dinosaur was also evidently quite social, and lived in groups as juveniles.

Skeletal anatomy of Oksoko avarsan: (a) skeletal reconstruction; (b, c) skull in left lateral view; (d) anterior cervical vertebra in left lateral view; (e) articulated sacrum and ilium in ventral view, anterior is to the left; (f) mid-caudal vertebra in left lateral view; (g) pygostyle vertebrae in left lateral view; (h) right scapulocoracoid in lateral view; (i) furcula in anterior view; (j) right and left sternal plates in anterior view; (k) articulated pelvis in right lateral view; (l) right femur in posterior view; (m) proximal metatarsus and distal tarsals in proximal view; (n) tibia, fibula and pes in ventral view. Image Credit: Funston et al

This animal would have lived in large, sandy deserts spotted with oases, foliage and riverbeds, home to a menagerie of dinosaur life. The Nemegt Formation boasts some of the world’s largest variety in theropods, from avimimids to dromaeosaurids to even tyrannosaurids. Some exceptionally famous species such as Gallimimus, Deinocheirus, Tarbosaurus, and even giant azhdarchid pterosaurs would have graced this spectacularly diverse habitat. The discovery of Oksoko gives us a clearer picture of this prehistoric landscape, and gives us perspective on how well dinosaurs were doing evolutionarily before the K/T impact event.


  • Gregory F. Funston¬†et al. 2020. A new two-fingered dinosaur sheds light on the radiation of Oviraptorosauria.¬†Royal Society Open Science¬†7 (10); doi: 10.1098/rsos.201184

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