Frontal bones of non-avian theropod dinosaurs from the Upper Cretaceous (Santonian-?Campanian) Bostobe Formation of the northeastern Aral Sea region, Kazakhstan

Three theropod taxa have been identified based on isolated frontal bones from the Santonian-?Campanian Bostobe Formation at the Shakh-Shakh locality, in the northeastern Aral Sea region of Kazakhstan. A frontal referable to Ornithomimosauria indet. is distinct in having a slightly pronounced cerebral dome. A frontal of an unidentified therizinosaur resembles the element in Erlikosaurus (Cenomanian-Turonian of Mongolia) in most features, but it differs in having an anterolateral prong along the orbital rim, a less-developed facet for contact with the prefrontal, and a larger depression for the cerebral hemisphere. A frontal identifiable as Troodontidae indet. differs from that of Troodon (Campanian-Maastrichtian of North America) and resembles that of the Mongolian Campanian Gobivenator in having a larger supratemporal fossa and the anterior process of the parietals wedged between the frontals. This specimen is the first reliable record for Troodontidae from the Bostobe Formation.