The teeth of the upper and lower jaw contain bump rows that fit together perfectly in order to maintain an accurate bite. "Oligokyphus" had a face similar to that of modern mammals, although there were differences in the cheekbones and eye sockets. It had a bony secondary palate and double-rooted cheek teeth. Unlike mammals, the teeth of "Oligokyphus" did not occlude. The jaw was double jointed, and the neck was flexible, with an atlas and axis and a double occipital condyle.