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
Petrous part of the temporal bone DNA. Petrous part of the temporal bone The petrous part of the temporal bone is pyramid-shaped and is wedged in at the base of the skull between the sphenoid and occipital bones. Directed medially, forward, and a little upward, it presents a base, an apex, three surfaces, and three angles, and houses in its interior, the components of the inner ear. The petrous portion is among the most basal elements of the skull and forms part of the endocranium. Petrous comes from the Latin word "petrosus", meaning "stone-like, hard". It is one of the densest bones in the body. The