Dietary negation

The hominin genus Paranthropus rarely hits the front page by comparison with the related australopithecines, despite their having had jaw and cheek bones that would put Sandy Shaw and a variety of 60s catwalkers to shame. (It is only polite to observe that there the vague similarity ends, for paranthropoids have a bizarre skull crest for attachment of jaw muscles and brow ridges that were probably better than a baseball cap at preventing glare.) The first (P. boisei) to be unearthed at Olduvai, Tanzania in 1959, was dubbed ‘Nutcracker Man’ by its finder Philip Tobias. Despite having formidable chewing tackle to drive its massive flat, thickly enameled cheek teeth, wear on their surfaces is little different from that on the teeth of ‘gracile’ australopithecines. (Ungar, P.S. et al. 2008. Dental Microwear and Diet of the Plio-Pleistocene Hominin Paranthropus boisei. PLoS ONE, v. 3, on-line e2044 ( doi:10.1371/journal.pone.0002044). They show no sign of the microscopic pitting that characterises teeth of living primates that eat hard, brittle foods, such as nuts or woody stems.  Similar studies of the teeth of P. robustus show insufficient wear to suggest an habitual diet of that kind, although it may have eaten such foods when others were in short supply. Chances are that huge jaws and big teeth evolved to give paranthropoids a wider choice of diet and hence greater fitness in a climatically fluctuating terrain. It seems they chose to eat soft foods when available, as do gorillas today. In any event, they were remarkably successful creatures, and the two species cohabited the East African savannah with several human species, including H. erectus, for around a million years from 2.2 Ma when they appeared. Carbon-isotope data obtained from 20 paranthropoid and 25 australopithecine teeth by other researchers reveal a broad but similar diet for both, i.e. a mix of grasses and fruits, suggesting both had eating habits that could shift from apes to those of baboons. However, such C-isotope data cannot distinguish between exclusive vegetarianism and eating the flesh of herbivores. Low dental wear is also associated with meat eating…

See also: Gibbons, A. 2008. Australopithecus not much of a nutcracker. Science, v.  320, p. 608-609; part of a report on the April 2008 meeting of the American Association of Physical Anthropologists

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