Frecuencia del hueso interparietal o incaico en cráneos atacameños (lican antai) prehispánicos del norte de Chile

Abstract

The interparietal bone is considered an intercalary bone originated by independent ossification centers and surrounded by its own sutures. It is found in early hominids and human fossils. It is believed that the occipital bone undergoes transformations by mutations at the beginning of human evolution. Reinforcing this theory are the suture variations that presents the occipital bone. It would be a dominant genetic characteristic, proposal ratified by experimental studies. It is observed with varied forms according to the fusion of the ossification nuclei; reason why all the bones located in the zone of the occipital flake cannot be classified as sutures or wormians and must be considered part of the interparietal bone. Trying to confirm the high frequency obtained in previous investigations realized in skulls of original individuals of the north of Chile, we analyzed 83 skulls of pre-Hispanic atacameños (lican antai) of both sexes, selected at random between 293 individuals of the Coyo-Orient cementery, dated between 300-1200 A.C., post-Tiwanaku period and these remains are part of R.P Gustavo Le Paige's Museum in San Pedro de Atacama, which is part of the Institute of Archaeological Investigations of the North Catholic University. The remains were photographed in all anatomical norms and that were measured to obtain the cranial or cephalic index. The interparietal bone is present in 23 of 83 skulls, with a frequency of 27.71%, without significant statistical differences to 95% with investigations realized in skulls of similar ethnic origin and other ethnic groups who present high frequency of interparietal bone. On the contrary, statistically significant differences to 95% were found with frequencies determined in caucasian and euroasiatics european skulls. The authors integrated the classificatory tables of Kadanoff and Hanihara-Ishida, to obtain a modified table that allowed to classify all the found variations of the interparietal bone. Brachycephalization is verified, confirming that the increase in cranial supernumerary bones is associated to this cranial form.