Tooth Analysis May Decipher Prehistoric Diets

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Tooth analysis may decipher prehistoric diets

Scientists say they have indentified the microscopic "fingerprints" of plant remains on the fossil teeth of Gigantopithecus, a huge Asian ape that lived from 6 million to 300,000 years ago. The evidence suggests that the extinct ape -- which stood an estimated 10 feet tall and weighed more than 1,00 pounds -- ate a varied diet, including both tropical fruits and fibrous grasses. If the dental decoding technique proves accurate, it may one day illuminate the feeding habits of other extint animals, including human ancestors.

For now, analyses of plant residues on fossil teeth remain preliminary, says paleoanthropologist Russell Ciochon of the University of Iowa in Iowa City. Indeed, several paleontologists argue that no solid evidence links the tiny particles studied bu Ciochon's group to the diet of living or extinct animals.

A scanning electron microscope revealed 30 floral fingerprints, known as phytoliths, on two out of four Gigantopithecus teeth under study, Ciochon and his co-workers report in the October PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES (Vol. 87, No. 20). Monosilicic acid travels throughout a plant's vascular system and hardens inside and between the cells to create the phytoliths -- remarkably durable silica impressions of the plant cells. Many plants and all grasses absorb the monosilicic acid as their roots take up groundwater.

"Phytliths are widespread throughout the plant kingdom," says archaeologist and study participant Dolores R. Piperno of the Smithsonian Tropical Research Institute in Balboa, Panama.

Scientists first identified phytoliths nearly 150 years ago in Germany, and studies of phytoliths found in soil began in the 1950s. Since then, the hardy silica bits have turned up on stone tools un-earthed at several archaeological sites. Piperno has identified phytoliths from more than 1,300 species of tropical plants, mainly in South America, as well as 19 plant species from three families native to a region of China where Gigantopithecus teeth and jaws have been found. …