Xenocretosuchus is an extinct genus of tritylodont therapsids from the Aptian (Early Cretaceous) Ilek Formation of Siberia, in the Russian Federation.[1] The type species, X. sibiricus, is known only from dental elements,[2] as is X. kolossovi, described from the Batylykh Formation in 2008.[3] Some authors have treated these species as part of the genus Stereognathus, otherwise known from the Middle Jurassic of Britain,[4] but this is rejected by other authors.[5]
Alongside Montirictus and Fossiomanus, it is amongst the latest known non-mammaliform synapsids, extending their range to the Early Cretaceous.