LIVERPOOL, ENGLAND—Science Magazine reports that paleontologists led by Ian Towle of Liverpool John Moores University suggest Paranthropus robustus, a hominin that lived in southern Africa some 1.8 million years ago, may have been susceptible to a disorder that caused golf ball–like pits on the surface of its teeth. Fossil specimens of thick P. robustus molars are often found in poor condition. The creature is thought to have lived on a diet of tropical grasses, hard seeds and nuts, and fibrous fruits, but scientists had not been able to determine whether the rough diet could have caused the pitting of tooth enamel and weakened the teeth so that they would have worn down more quickly and perhaps broken more easily. The new study compared P. robustus teeth with the teeth of other hominins and living apes, and found the pitting occurred in 47 percent of P. robustus baby teeth and 14 percent of their permanent teeth, but in only seven percent of the baby teeth of other hominins, and four percent of their adult teeth. The researchers note the similarity of the condition to a rare genetic disorder known as amelogenesis imperfecta, which can damage cells that produce enamel, but is also associated with production of thick, dense enamel. Towle and his colleagues concluded that the more frequent occurrence of pitting may have been a side effect of the evolution of teeth strong enough to cope with the tough, gritty diet consumed by P. robustus. To read about archaeological evidence of early dentistry, go to “Not So Pearly Whites.”
