Hip bone The hip bone first appears in fishes, where it consists of a simple, usually triangular bone, to which the pelvic fin articulates. The hip bones on each side usually connect with each other at the forward end, and are even solidly fused in lungfishes and sharks, but they never attach to the vertebral column. In the early tetrapods, this early hip bone evolved to become the ischium and pubis, while the ilium formed as a new structure, initially somewhat rod-like in form, but soon adding a larger bony blade. The acetabulum is already present at the point where the three
Petrous part of the temporal bone anterior angle is divided into two parts—a lateral joined to the squamous part by a suture (petrosquamous), the remains of which are more or less distinct; a medial, free, which articulates with the spinous process of the sphenoid. At the angle of junction of the petrous and the squamous parts are two canals, one above the other, and separated by a thin plate of bone, the septum canalis musculotubarii; both canals lead into the tympanic cavity. In ancient DNA studies, scientists extract and sequence DNA from ancient skeletal remains of humans and other species. In many cases the DNA is