The evolution of the posterior cranial vault in the central European Upper Pleistocene.

Abstract

The relationship between Neandertals and the people who followed them in Europe is one of the most interesting topics in paleoanthropology. The morphology of the occipital region has been observed to vary between Neandertals and modern humans, and historically this variation has been interpreted taxonomically. However, the actual differences in posterior cranial vault morphology between Neandertals and the earliest Upper Paleolithic Europeans has never been documented. Much of this variation may have functional significance, as this anatomical region is affected by many muscles. Therefore variation in this region may be influenced by and give insights into variation in habitual behaviors. The earliest Upper Paleolithic remains known are from central Europe, as is the largest Neandertal occipital and posterior temporal sample from a single site. All of the Neandertal and early Upper Paleolithic remains from central Europe were studied in detail. This fossil material comes from the Mousterian sites, Krapina, Vindija, and Salzgitter-Lebenstedt, the Aurignacian sites, Mladec, Stetten, and Cioclovina, and the Pavlovian sites, Pavlov, Predmosti and the Francouzska street locality in Brno. Differences in the morphology of the posterior cranial vaults in the Neandertals and the early Upper Paleolithic samples are detailed. From this analysis, systematic patterns that characterize the two samples are abstracted. These patterns suggest a functional framework that associates variation on the occipital plane of the occiput with variation on the nuchal plane, and therefore nuchal muscle variation. The two patterns can be related to two independent factors; the magnitude and expression of lambdoidal flattening, and the muscle action related variation that affects the nuchal plane. These are functionally related. The difference in lambdoidal flattening affects the vertically oriented posterior surface of the cranial vault. This surface is higher and more medially restricted in the Upper Paleolithic specimens than in Neandertals. The corresponding nuchal plane variation emphasizes the development of the superior nuchal line, reflecting the action of the first layer nuchal muscles that are active in various forms of upper limb loading. Neandertals, on the other hand, have wider and more extensive lambdoidal flattening, a shorter vertical surface to the posterior vault, and a transverse occipital torus that is different from the condition found in the earliest Upper Paleolithic sample. Neandertal morphology emphasizes the development of large second layer nuchal muscles (m. semispinalis capitis) that insert across much of the width of the occiput. These muscles are important in head stabilization and extension. I suggest that these different morphologies reflect different patterns of habitual muscle use, although not necessarily a qualitative change in behavior or the replacement of one behavior by another. The morphology supports hypotheses of anterior tooth loading in Neandertals and individual and residential mobility in Upper Paleolithic populations.Ph.D.ArchaeologyPhysical anthropologySocial SciencesUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/128680/2/9123988.pd