2023 Author: Bryan Walter | [email protected]. Last modified: 2023-05-21 22:24
Ancient hominins who lived in China 224-104 thousand years ago turned out to be very similar to one of the features of Homo sapiens. As the researchers write in Science Advances, their teeth developed slowly, along about the same "schedule" as the teeth of modern humans. Scientists associate the speed of tooth development with the long development and late maturation characteristic of sapiens.
In the 70s of the last century, the remains of a hominin were discovered in Xujiao in northeastern China. According to various estimates, they lived 224-161 thousand or 125-104 thousand years ago. Recent studies have shown (1, 2) that the structure of hominins from Xujiao had both archaic features inherent in Homo erectus and features inherent in Neanderthals and modern humans. Recently, after analyzing the morphology of the teeth of a hominin from Xujiao, the researchers suggested that they could be Denisovan people (they are known to us from separate bones of the skeleton and several teeth).
Scientists from seven countries, led by Song Xing of the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences, examined the remains of Xujiao 1, a boy of about six and a half years old, from whom remained part of the right upper jaw and seven preserved teeth in it. The researchers made a computed tomography of the remains, analyzed the features of the development of the boy's teeth and compared them with the features of ancient and modern people.
The study of dental development may help to understand how similar the hominins from Xujiao were to Homo sapiens. Among other features, modern people differ from other types of people in the development of their teeth. For example, our tooth enamel grows more slowly and the crown part of the tooth is formed. Compared to other living primates and extinct humans, Homo sapiens grows more slowly molars. Researchers associate these traits with longer development and late maturation, key traits of modern humans.
It turned out that the development of teeth in the boy Xujiao 1 and Homo sapiens was very similar. For example, one of his molars grew several months before his death, and the root of the tooth was not fully formed. The coronal parts of his teeth were formed at the same rate as in modern children; the distribution of periquimates - lines on the surface of the teeth that appear during the growth of enamel - was similar to that of the Sapiens rather than the Neanderthals. “We found that the boy developed, at least his teeth and in modern humans grew on a similar“schedule,”says one of the study's authors, Maki O'Hara from Ohio University.
Earlier, anthropologists learned to determine the sex of ancient people by the composition of tooth enamel. Using mass spectrometry, they determined the composition of the protein amelogenin in enamel, which is slightly different in men and women.