the mandible articulates with the skull at the articular bone.
the mandible articulates with the skull at the articular bone.
where does the mandible articulate with the skull?
the articular bone
the mandible (lower jaw) is one of the best preserved parts of the skull. it was robust, especially at the front third of its length. the tomial crest was straight for its entire length, and a notch indented the sharp tip of the mandible. the mandible was spear-shaped in side view, due to its lower margin slanting downwards and back from its tip for the front third of its length (the jaw was also deepest at a point one third from the tip). the symphyseal part (where the two halves of the lower jaw connected) of the dentary was very robust. the lower margin formed an angle at the level of the front margin of the nasal foramen, which indicates how far back the rhamphotheca of the beak extended. the dentary had three processes that extended backwards into other bones placed further back in the mandible. the articular bone at the back of the mandible was completely fused with the surangular and prearticular bones. the mandible extended hindwards beyond the cotyla (which connected with the condyle of the upper jaw), and this part was therefore similar to a retroarticular process as seen in other taxa. the surangular enclosed two mandibular fenestrae. the hindmost part of the surangular had a small foramen placed in the same position as similar openings in the mandibles of non-bird theropods and modern birds. the splenial bone was three-pronged (as in some modern birds, but unlike the simple splenial of "archaeopteryx"), and its lower margin followed the lower margin of the mandible. there was a large rostral mandibular fenestra and a small, rounded caudal fenestra behind it.
confuciusornis
d2700 and d2735 were found in 2001, just a decade after the first discovery of an early hominin mandible d211 at dmanisi on september 24, 1991. in 1999, partial crania d2280 and d2282 were discovered. cranium d2282 is likely the accompanying skull to mandible d211 and to be the remains of a young adult around 18–20 years old. skull d2280 is inferred to have been an adult around 25–30 years old at the time of death. moreover, in 2005, a new complete skull cranium was found: d4500. this cranium is inferred to be an adult skull and is more commonly known as “skull 5.” d4500’s features are very rare compared to early "homo" in that it had a small braincase yet an unusually large prognathic face. “skull 5” has an accompanying mandible, d2600, which was found in 2000.
dmanisi skull 3