Abstract: Two petrosals from the Late Oligocene of the northern Junggar Basin, Xinjiang Uygur Autonomous Region of China are described and are assigned to ?Yindirtemys and ?Sinolagomys or Desmatolagus based on sizes and morphologies. The unit formed by a fused bulla and petrosal, the spongy bullar wall and the anterior position of the entrance for the stapedial artery into the tympanic cavity indicate that petrosal A is most likely from an ochotonid. Absence of grooves and foramina for the internal carotid artery around the promontorium suggests petrosal B probably belongs to the ctenodactylid Yindirtemys. If the identifications are confirmed，these specimens represent the first records of ear regions in the two taxa.