( Recent research suggested that ancient ...)Neanderthal teeth grew no faster than comparable modern humans'

They found that the rate of tooth growth present in the Neanderthal fossils they examined was comparable to that of three different populations of modern humans.

And since the rate of tooth growth has become a more-accepted tool for estimating the length of childhood among hominids, the finding is the latest evidence suggesting that Neanderthals may not have been as different from modern humans as some researchers have thought.

The study by Debbie Guatelli-Steinberg, assistant professor of anthropology at Ohio State , appeared in the current issue of the Proceedings of the National Academy of Sciences. Donald J. Reid, lecturer in oral biology at the University of Newcastle , Thomas A. Bishop, associate professor of statistics, and Clark Larsen, professor and chair of anthropology, both at Ohio State , were co-authors in the study.

"Based on our study of the enamel of these Neanderthal teeth and other modern ones, we can't support the claim that Neanderthals grew up more quickly than do modern humans," she said.

Key to this conclusion are microscopic lines on the outside of teeth that mark the incremental growth of enamel on a young tooth. Like tree rings that can gauge the age of a redwood, these striations ?called perikymata ?record new growth on the surface of the tooth.

Researchers know from earlier work that these markings are present in all forming teeth, signifying six to 12 days of growth. By multiplying that interval by the number of perikymata on a tooth's surface, researchers can gauge how long it took for the tooth to mature. And that gives them an indication of the length of an individual's childhood.

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Source:Ohio State University