Describer

Longrich, Currie, Dong 2010

Time

Cretaceous Late Campanian

Classification

Saurischia Theropoda Tetanurae Coelurosauria Maniraptora Oviraptorosauria Ingeniidae

Diet

Carnivore

Fossilsite

Wulansuhai Formation former Bayan Madahu Formation, Inner Mongolia, China

Info

Abstract

A new oviraptorid is described on the basis of a partial forelimb collected from the Upper Cretaceous redbeds of Bayan Mandahu, Inner Mongolia. Machairasaurus leptonychus, gen. et sp. nov. is diagnosed by slender, weakly curved manual unguals, reduced flexor tubercles, penultimate phalanges that are subequal in length to the preceding phalanges, and short, robust manual digits. Machairasaurus is found to be a member of the Ingeniinae, along with Ingenia yanshini, Heyuannia huangi, Conchoraptor gracilis, and Nemegtomaia barsboldi.

Machairasaurus exhibits unusual proportions of the manus, suggesting that the manus was not primarily used to grasp prey. Instead, Machairasaurus and other oviraptorids are likely to have fed largely on plant material. The recognition of a previously unknown oviraptorid at Bayan Mandahu provides further evidence that the Bayan Mandahu dinosaur assemblage is distinct from that found at the Djadochta Formation exposures at Bayn Dzak, [[Turginskaya Svita [Tugriken Shireh]] and Ukhaa Tolgod. Given that these localities are separated by just a few hundred kilometres and represent similar palaeoenvironments, marked differences in the fauna suggest that the Bayan Mandahu Formation of Inner Mongolia is not coeval with the known Djadochta localities in Mongolia.