Aphanosauria archosaurs (apart from specialized forms like pterosaurs or theropod dinosaurs). The pelvis (hip) of aphanosaurs shares many similarities with those of early dinosaurs and silesaurids as well as the unrelated poposauroids. Most of these traits can be found in the ischium, a plank-shaped bone which makes up the lower rear branch of the hip. For example, each ischium (on either side of the hip) contacts each other at the hip's midline. This contact is very extensive, although they are not completely fused due to the contact not extending to the upper edge of each bone. In contrast, pterosaurs, lagerpetids, and
Squamous part of occipital bone eminence. The upper two fossae are triangular and lodge the occipital lobes of the cerebrum; the lower two are quadrilateral and accommodate the hemispheres of the cerebellum. At the point of intersection of the four divisions of the cruciform eminence is the internal occipital protuberance. From this protuberance the upper division of the cruciform eminence runs to the superior angle of the bone, and on one side of it (generally the right) is a deep groove, the sagittal sulcus, which lodges the hinder part of the superior sagittal sinus. To the margins of this sulcus the falx cerebri is attached.