The late Early Cretaceous (Aptian) tritylodontid synapsid Xenocretosuchus sibiricus from Western Siberia, Russia, exhibits a dentary–squamosal contact formed by a distinct condyloid process. This is a new case of independent development of the dentary–squamosal jaw articulation in synapsids, after that observed in derived ictidosaurs and mammaliaforms. The articular process of the dentary is remarkable for its length and is separated by a deep cleft from the condyloid process in Xenocretosuchus. It is hypothesised that the former covered the quadrate and the postdentary bones dorsally. The main function of the quadrate and the postdentary bones was sound transmission, suggesting that the dentary–squamosal articulation played the main role in load bearing in Xenocretosuchus. This is supported by the extreme development of the mandibular middle ear in Xenocretosuchus which may be related to the fossorial adaptations seen in the late surviving tritylodontids.