The enamel growth in the earliest fossils attributed to Homo erectus does not resemble that of modern humans in its development, wrote researchers in the Dec. 6 issue of Nature.
Scientists studied daily growth patterns preserved in the enamel of fossilized teeth to determine when modern adolescence emerged. Great apes take 12 years to grow up, while humans take 18 to 20 years.
Researchers used daily incremental markings in tooth enamel to calculate the rates of enamel formation in 13 fossilized teeth from three species of H. erectus. They identified differences in this key determinant of tooth formation time among H. erectus and modern humans and modern African great apes. None of the fossils shared the slow trajectory of enamel growth typical in modern humans. Instead, their growth patterns resemble those of modern and ancient African great apes.
Researchers concluded it seems likely that truly modern dental development emerged relatively late in human evolution.
