Paranthropus Boisei - Morphology and Interpretations

Morphology and Interpretations

The brain volume is quite small, about 500 and 550 cm³, not much larger in comparison to Australopithecus afarensis and Australopithecus africanus. or modern day chimpanzees. Unlike the P. robustus, the P. boisei feature a much shorter foramen magnum. Additionally the cranial variation of P. boisei is remarkably high. The average adult males were larger than females (sexual dimorphism), as was the case in virtually all australopithecine species. Males weighed 49 kg (108 lb) and stood 1.37 m (4 ft 6 in) tall, while females weighed 34 kg (75 lb) and stood 1.24 m (4 ft 1 in) tall.

It had a skull highly specialized for heavy chewing and several traits seen in modern day gorillas. P. boisei inhabited savannah woodland territories. The back molar teeth were relatively large, with an area over twice as great as is found in modern humans. The species is sometimes referred to as “Nutcracker Man” because it has the biggest, flattest cheek teeth and the thickest enamel of any known hominin.

Paranthropus boisei had large chewing muscles accompanied by a strong sagittal crest. Due to the fact that their face is so wide P. boisei also featured enormous cheek teeth, four times the size of modern humans. Although they have such enormous molar and cheek teeth the frontal teeth are much smaller than similar species.

Some argue that the craniodental morphology of this taxon (e.g., large postcanine dentition, thick enamel, robust mandibles, sagittal cresting, flaring zygomatic region) are indicative of a diet of hard or tough foods such as ground tubers, nuts and seeds. However, research on the molar microwear of P. boisei found a microwear pattern very different than that observed for P. robustus in South Africa which is thought to have fed on hard foods as a fallback resource. This work suggests that hard foods were an infrequent part of its diet. The carbon isotope ratios of P. boisei suggest it had a diet dominated by C4 vegetation unlike P. robustus in South Africa.