Transverse basilar cleft detected in prehistoric Jomon skulls from Japan

Abstract

The basilar part of the occipital bone is occasionally partially divided by lateral notches, termed transverse basilar clefts (TBCs). In the present paper, we describe the condition of the TBC in six skulls from prehistoric Jomon sites in the Japanese archipelago and then compare TBC frequencies between the Jomon and recent Japanese cranial series. The frequencies of TBCs in Jomon skulls from the southern Hokkaido and Tohoku districts are higher than in recent Japanese specimens from the Tohoku district. Since the TBC is considered a variation that appears at an early developmental stage in the human cranium, it is worthwhile investigating this trait as one of the nonmetric cranial variants in various human population groups, including immature individuals.