June 27, 2012
Australopithecus sediba: The Wood-Eating Hominid
The dental plaque on Australopithecus sediba teeth reveals the species ate wood or bark. Image courtesy of Amanda Henry
Sometimes it’s good to have something stuck in your teeth—good for science, anyway. New research on food particles clinging to two-million-year-old teeth reveal Australopithecus sediba, a possible ancestor of the genus Homo, had unusual dining habits for a hominid: The species consumed wood.
Discovered in South Africa in 2010, A. sediba is known from two partial skeletons. To reconstruct the species’ diet, Amanda Henry of the Max Planck Institute for Evolutionary Anthropology in Germany and colleagues relied on three methods. First, they looked at the markings on molar surfaces made by food as it’s being chewed. This analysis showed A. sediba ate hard objects, just as the South African hominid Paranthropus robustus did.
Next, the team looked at the carbon chemistry of the teeth. As a tooth forms, it takes up carbon from the food an individual eats. Forest plants such as trees, fruits and leaves (called C3 plants) have a different ratio of carbon isotopes than does grassland vegetation (C4 plants). The carbon in the teeth of A. sediba indicates the hominid dined almost exclusively on C3 plants, making it similar to some modern chimpanzees. Other early hominids likewise preferred C3 plants, but also included at least some C4 vegetation in their diet.
Finally, the researchers scraped off some of the dental plaque from two teeth of one of the known A. sediba skeletons. In the plaque were plant phytoliths, microscopic silica structures that form in plant cells. Different plants have distinctively shaped phytoliths, allowing scientists to use the structures to infer what ancient animals were eating. The team found 38 phytoliths, the first ever recovered from an early hominid. The phytoliths show A. sediba ate some water-loving C3 grasses and sedges as well as fruit, leaves and bark or wood. It’s the first evidence of a hominid eating wood, the researchers report in Nature.
The evidence of wood eating comes from just one individual, so it’s hard to know if this behavior is representative of the whole species. But the researchers point out the apparent reliance on wood and other forest plants fits with the skeletal evidence that suggests A. sediba climbed trees. Anthropologists have often suggested early hominids retained climbing abilities so they could find safe sleeping spots in the treetops. But maybe A. sediba was up there looking for breakfast, lunch and dinner.
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View this Johns Hopkins University video about this research here: http://bit.ly/LtoozD
It was a time when the “possible ancestor of the genus Homo” was indeed a true occupant of the species forest. We walked out of that species forest never to return.
Thanks, very interesting study: sediba’s diet included (papyrus?) sedges, part of palm trees etc. It confirms australopiths were swamp forest & wetland dwellers, somewhat resembling lowland gorillas in forest bais. East-African apiths were probably more herbi-, South-African ones more omnivorous. Apiths were no direct ancestors of ours, but were closer to the Homo-Pan-Gorilla common ancestors.
M.Verhaegen, S. Munro, P-F.Puech & M.Vaneechoutte 2011 in M.Vaneechoutte cs.eds “Was Man more aquatic in the past?” ebook Bentham scient.publ. pp.67-81:
… most australopiths were aquarboreals in inland wetlands:
- Their fossils have been found in Pliocene wet forests and in Pleistocene more open wetlands: gallery forests, lakeside grasslands, riverside reedbeds, papyrus swamps, montane lakeside forests, shallow lagoons etc. [1,3].
- Their postcrania suggest they might have waded and walked regularly on two legs and later also on their knuckles, and climbed arms overhead in the trees, eg, for sleeping, refuge, or fruit gathering. This fits their bipedal footprints (Laetoli), skull pneumatization and large laryngeal airsacs (Dikika), curved phalanges, upward oriented shoulder joints, toeing-in of feet and knuckle-walking features of wrists (Lucy), and very long arms in later australopiths (Omo L.40-19).
- Their broad and heavy jaws with molarized premolars and broad blunt cheek teeth (bunodonty), very thick enamel, and polished micro-wear [33,49] suggest wetland diets of hard-shelled invertebrates, eggs, fruits, nuts, floating plants, sedges, papyrus parts etc. Very thick tooth enamel combined with stone tool use are typically seen in hominids-pongids, capuchin monkeys and sea otters, and suggest a diet including hard foods like nuts or shelled molluscs (durophagy): capuchins crack nuts with stones, and use shells to remove oysters from mangrove trunks [54], and sea otters open seafoods with stones and have flat australopith-like cheek teeth [55].
Our view of australopiths as wetland dwellers [33,49,51] has recently been supported: Alan Shabel [44,56] compares australopiths with durophagous Carnivora in wetlands, Nikolaas van der Merwe [57] argues A.boisei may have fed on papyrus, and Richard Wrangham [42] thinks aquatic plants were possible fallback foods for early hominids …
Has anyone done a comparative anatomy study between Australopithecus and the Bonobo (dwarf chimp) either the Australopithecus is an ape or the Bonobo is a protohominid.
You might be interested in our fothcoming conference on human evolution (with David Attenborough, Don Johanson etc.):
Human Evolution conference London 8–10 May 2013
http://www.royalmarsden.nhs.uk/education/education-conference-centre/study-days-conferences/pages/2013-evolution.aspx
Was Man more aquatic in the past? eBook
http://www.benthamscience.com/ebooks/9781608052448/index.htm