The supra-acetabular fossa and groove: a skeletal marker for Northwest European mesolithic populations

A nonmetric trait, known as the supra-acetabular fossa and groove, is described for European Upper Paleolithic and mesolithic populations. This morphological feature consists of a pit posterior or superior to the anterior-inferior iliac spine and an associated groove which arcs over the roof of the acetabulum. Presence of the trait seems to be primarily related to the origin of the reflected head of rectus femoris. The trait is variable in its expression, shows an increase in definition with age, and occurs equally in males and females. Although the trait is commonly found in pre-Upper Paleolithic hominids, it is extremely rare in the Upper Paleolithic, limited to a single occurrence in the Oberkassel 2 female. In the Mesolithic, except for two innominates from Vlasac (Yugoslavia), the trait is found only in NW European populations, especially Skateholm (Sweden) and Henriksholm-Bøgebakken (Denmark) where it occurs in more than 50% of the known pelves. Given the trait’s restricted geographic distribution and high occurrence in Skateholm and Henriksholm-Bøgebakken, it is suggested the supra-acetabular fossa and groove represents a skeletal marker for NW European Mesolithic populations. As such, it provides evidence for the development of social territories in the early Holocene.