In the jaw of one of the Homo antecessor from the Sierra de Atapuerca (Spain), a third molar (wisdom tooth) was found in a non-physiological position, according to the American Journal of Physical Anthropology. It grew over the second molar, although they should normally be located next to each other. This means that the place on the jaw for wisdom teeth might not have been enough already in very ancient European people.
In the course of evolution, the human ancestors decreased their jaws and increased the cerebral part of the skull. It is assumed that as a result of this, at some point, the teeth began to lack space on the jaws, and therefore the wisdom teeth - the third, the most posterior molars - quite often occupy the wrong position or do not erupt to the end.
This is observed in 15-20 percent of modern Homo sapiens of European origin, and it is rather rare among the paleoanthropological material. Most often, wisdom teeth are nonphysiologically placed on the jaws of Neanderthals (and this was probably a hereditary deviation), although two such cases are also known for Australopithecines.
Scientists from the University of Bordeaux (France), the National Research Center for Human Evolution and the University of Rovira and Virgili (Spain) found that the wrong position of wisdom teeth was also found in the human predecessor (Homo antecessor). They examined the jaw of a boy ATD6-69 from the TD6 level of the Gran Valley site in the Sierra de Atapuerca. It is assumed that this individual was 9-11 years old at the time of death. The total age of the find is about 850 thousand years.
The remains were examined visually, as well as using computer microtomography. This made it possible to create a three-dimensional model of the jaw and outline the contours of individual teeth on it. The researchers also took similar pictures and models for today's 36 boys and 38 girls between the ages of 4 and 12. Of these, only those were selected whose teeth were developed in approximately the same way as those of the studied human predecessor, but did not bear traces of anomalies.
Three-dimensional reconstruction of the second (blue) and third (blue) molars on the jaw Homo antecessor
The position of the molars (molars) on the boy's upper jaw
It turned out that on the left side of the upper jaw ATD6‐69, the third molar was growing above the second, and not next to it, as it would be if they had enough space. It is unclear whether this interfered with the child and what consequences it would have caused: he died too early for this to be understood. In modern children, sometimes the problem resolves itself if the jaws have time to lengthen enough. But, judging by the state of the bones and other teeth of the boy from the Gran Valley, his growth at the time of his death had almost stopped. So, probably, his wisdom tooth would forever remain in the wrong position and give him discomfort, causing tooth decay or other pathologies.
Homo antecessor is a species that combines primitive and advanced structural features. Apparently, the development of his teeth and the parameters of his face were more reminiscent of those of modern people, and the size of the teeth (they were large) was close to that of archaic species. What caused the incorrect position of the wisdom tooth in ATD6-69 - a short jaw or too large teeth, how great is the relative contribution of genetics and developmental conditions of this child, it is impossible to say for sure. However, the researchers do not exclude that the main factor here is too small a jaw.
The Sierra de Atapuerca is one of the richest places in Europe for paleontological and archaeological finds. There, in the Cave of Bones, they found the remains of Neanderthals about 430 thousand years old, which indicates their early divergence from the Denisovans. In the same cave, they found the first reliable evidence that violent fights took place between prehistoric people, which sometimes reached the point of murder.