Behavioral inferences from the Skhul/Qafzeh early modern human hand remains

Abstract

Two groups of humans are found in the Near East approximately 100,000 years ago, the late archaic Neanderthals and the early modern Skhul/Qafzeh humans. Observations that Neanderthals were more heavily muscled, had stronger upper-limb bones, and possessed unusual shapes and orientations of some upper-limb joint complexes relative to the Skhul/Qafzeh hominids, have led some researchers to conclude that significant between-group upper-limb-related behavioral differences must have been present, despite the association of the two groups with similar Middle Paleolithic archeological complexes. A three-dimensional morphometric analysis of the hand remains of the Skhul/Qafzeh hominids, Neanderthals, early and late Upper Paleolithic humans, and Holocene humans supports the dichotomy. The Skhul/Qafzeh carpometacarpal remains do not have any unique morphologies relative to the other fossil samples remains examined. However, in the functionally significant metacarpal 1 and 3 bases they resemble Upper Paleolithic humans, not Neanderthals. Furthermore, the Skhul/Qafzeh sample differs significantly from the Neanderthals in many other aspects of hand functional anatomy. Given the correlations between changes in tool technologies and functional adaptations seen in the hands of Upper Paleolithic humans, it is concluded that the Skhul/Qafzeh hand remains were adapted to Upper Paleolithic-like manipulative repertoires. These results support the inference of significant behavioral differences between Neanderthals and the Skhul/Qafzeh hominids and indicate that a significant shift in human manipulative behaviors was associated with the earliest stages of the emergence of modern humans.

Figure 1

Examples of grids projected on various recent human MC 1, 3, and 5 bases (A–C) and trapezium, capitate, and hamate MC facets (D–F). The landmarks are the digitized gridline intersections.

Figure 2

Examples of wire frames of the CMC facets visualized with the morphologika software. The range of shape variation along some of the principal components (PC) of shape that contribute significantly to discriminating Neanderthals from recent humans is illustrated in the morphing of the combined sample Procrustes mean facet shapes: the MC 3 base (1A–1C), the MC 1 base (2A–2C), and the distal capitate facets (3A–3C). Neanderthals tend to have less styloid projection, flat to convex MC 1 bases, and more parasagittally oriented capitate MC 2 facets.

Figure 3

Plots of the CMC facet canonical discriminant functions. The class means are plotted on the first two canonical axes for the MC 1 base, MC 3 base, MC 5 base, and the trapezium, capitate, and hamate MC facets.