The evolution of the jaw is thought to have facilitated encephalization, speech, and the formation of the uniquely human chin.
Researchers hypothesize that the earliest hominid ancestor would have similar dental morphology to chimpanzees today.
Major characterizing features of Pan troglodytes dental morphology include the presence of peripherally located cusps, thin enamel, and strong facial prognathism.
These skeletal pieces show dental features that include a U-shaped palate and canines smaller than those of a chimpanzee’s.
[6] In addition, there is less sexual dimorphism in the size of the canines, a feature that is seen in humans and is heavily contrasted to chimpanzees.
In great contrast to the social patterns of chimpanzees, the smaller upper canine teeth suggest that the species was not very aggressive, especially in terms of the relationship between males and other groups.
Compared to modern apes, A. afarensis and A. africanus have much smaller molars and canines, but they are still larger than those of humans’.
[9] The lack of shearing crests in the blunt teeth have also been cited as evidence of a species that could chew buds or flowers but they were still able to consume meat.
[8] Studies of Australopithecine diets through dental microwear showed that they were largely frugivorous but there is some archaeological evidence for meat consumption.
[8] Megadont hominids, in normal, show the greatest reduction in canines, but the premolars were abnormally large.
There is also evidence from muscle markings on jaws that robustus would have had a diet that was based on hard, tough to chew foods in times of nutritional stress.
The evidence from fossils shows morphological traits designed for chewing hard, tough foods and is commonly referred to as the ‘nutcracker man’.
However, in conjunction with dental evolution, it is expected that Homo habilis would display smaller teeth than those of the hominids before them.
Through analysis of specimens, the face of Neanderthals showed more prognathism, resulting in a retromolar space posterior to the third molar.
[3] The general characterizing feature of the dental morphology of humans are the lack of facial prognathism, a parabola-shaped mandible and maxilla, and molars that are the same size as the front teeth.
Humans also have small crowns in relation to body mass and tend to show a reduction in cusp and root number.
As the jaw changed and the muscles become weaker, the pressure on the cranial sutures lowered, and encephalization occurred.
Additionally, the evolution and reduction in the jaw has left little room for the third molar, or wisdom tooth, to form.