New evidence from Le Moustier 1: computer-assisted reconstruction and morphometry of the skull.

Abstract

In this study, we present a new computerized reconstruction of the Le Moustier 1 Neanderthal skull and discuss its significance for Neanderthal growth and variability. Because of the precarious state of preservation of the original material, we applied entirely noninvasive methods of fossil reconstruction and morphometry, using a combination of computed tomography, computer graphics, and stereolithography. After electronic restoration, the isolated original pieces were recomposed on the computer screen using external and internal anatomical clues to position the bone fragments and mirror images to complete missing parts. The inferred effects of general compressive deformation that occurred during fossilization were corrected by virtual decompression of the skull. The resulting new reconstruction of the Le Moustier 1 skull shows morphologic features close to the typical Neanderthal adult state. Residual asymmetry of skeletal parts can be traced to in vivo skeletal modification: the left mandibular joint shows signs of a healed condylar fracture, and the anatomy of the occipital region suggests mild plagiocephaly. Using micro-CT analysis, the left incus could be recovered from the matrix filling of the middle ear cavity. Its morphometric dimensions are similar to those of the La Ferrassie III incus. The morphometric characteristics of the inner ear deviate substantially from the condition reported as typical for Neanderthals and fall within the range of modern human variability.