We report here a neurocranial abnormality previously undescribed in Pleistocene human fossils, an enlarged parietal foramen (EPF) in the early Late Pleistocene Xujiayao 11 parietal bones from the Xujiayao (Houjiayao) site, northern China. Xujiayao 11 is a pair of partial posteromedial parietal bones from an adult. It exhibits thick cranial vault bones, arachnoid granulations, a deviated posterior sagittal suture, and a unilateral (right) parietal lacuna with a posteriorly-directed and enlarged endocranial vascular sulcus. Differential diagnosis indicates that the perforation is a congenital defect, an enlarged parietal foramen, commonly associated with cerebral venous and cranial vault anomalies. It was not lethal given the individual’s age-at-death, but it may have been associated with secondary neurological deficiencies. The fossil constitutes the oldest evidence in human evolution of this very rare condition (a single enlarged parietal foramen). In combination with developmental and degenerative abnormalities in other Pleistocene human remains, it suggests demographic and survival patterns among Pleistocene Homo that led to an elevated frequency of conditions unknown or rare among recent humans.
To the extent that these abnormalities can be considered congenital or
cannot be securely diagnosed, these considerations raise questions
regarding the population dynamics of Pleistocene humans. To what extent
could this pattern reflect small, highly inbred populations, which were
also demographically unstable, resulting in both the increased
appearance of congenital deleterious conditions and in their subsequent
disappearance through local population extinction? Demographic
instability appears to have been characteristic of most Pleistocene
human populations –.
It remains unclear, and probably untestable, to what extent these
populations were inbred, but close genetic relationships have been
suggested for one Neandertal sample  and some Upper Paleolithic burial groups , , .