22 trees, with a tree length of 100 and a rescaled consistency index of 0.279. This analysis clearly defines an erectine clade defined by African, eastern European, and Asian specimens as distinct from all others. The relationship between the Ceprano, Daka, and OH 9 specimens, as well as the populations defined by Steinheim, and the species H. heidelbergensis cannot be resolved (perhaps not surprising given that only 27 cranial features are used). Significantly, however, classic specimens of H. neanderthalensis have a deeper prehistory than that of the derived H. sapiens clade; i.e., early H. sapiens, the Herto, Cro-Magnon (CM), and Kow Swamp populations (KS). Indeed, let us remember that early H. sapiens and Herto are substantially older in time than the Neanderthals. To further test the significance of these results, a bootstrap analysis was run on these 27 characters, with 1,000 replications. This resulted in greater resolution of proposed relationships, with H. heidelbergensis emerging after the older Pleistocene hominins; this is followed by the Steinheim group, and then the
Neanderthals. It is only after the emergence of the Neanderthal lineage, however, that we observe the appearance of the modern human condition first defined by Herto, then early sapiens, then finally Cro-Magnon and Kow Swamp. Both of these analyses clearly support the emergence of the modern human lineage after the emergence of the Neanderthals, which rejects the Multiregional hypothesis.
The remaining features that are said to support a regional continuum between the middle Pleistocene Indonesian hominins and the late Pleistocene Australasians are largely functional in origin. These features include a developed nuchal torus, a large robust mandible, and a large postcanine dental complex (Thorne & Wolpoff, 1981, 1992; Wolpoff et al., 1984; partly P. Brown, 1981). They are associated with the development of the masticatory apparatus and in vivo responses to diet. They are closely integrated as a functional complex and should not be isolated as individual features.
As Wolpoff (1971) has shown, a large dental complex is observed in the sub-Saharan Africans, second only to Australians (see also D.E. Lieberman, 1995). These and other modern human groups were in most cases dependent on the mastication of largely unprepared food resources (little preparation before consumption), with the molars pulping and grinding tough food items. Selective pressures would result in an increase in the dental complex, for a biomechanical failure to cope with such stresses would result in early death.
In order to house a large dental complex, one requires a large robust mandible, with its associated musculature. Clearly a small mandibular frame housing a large dental complex will result in masticatory stresses, associated with mandibular wishboning and twisting of the mandible along its long axis, and these will result in disastrous compressive and tensile stress and a breakdown of the masticatory system (see Hylander, 1984, 1988; Aiello & Dean, 1990; McGowan, 1999; Martin et al., 1999).
The development of skeletal form, including the mandible, continually works to provide a state of balance between separate entities as they merge and grow into a "single" functional whole (Enlow & Hans, 1996). A state of balance never really exists because other morphological units are forced to change in response to local "adaptations," which in turn propel changes elsewhere; there is a continual game of "catch-up" between muscle mass and bone mass. Any local change will result in a domino effect throughout the soft tissue and skeletal systems as it adapts to the corresponding changes (Enlow, 1982; Enlow & Hans, 1996; Martin et al., 1999). The major muscles of mastication, the masseter, temporalis, and pterygoids, require significant muscle attachment sites. The same applies to the neck muscles controlling the rotation of the head, the sternocleido-mastoideus, and the rectus capitis posterior muscles, and these will affect the development of the nuchal crest and the mastoids.
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