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Neanderthals are the best represented and most studied group in the fossil human record. The relatively large number of Neanderthal fossils and their good preservation offers the possibility of robust inferences about their evolution and paleobiology. Nevertheless, debate still continues on important issues, and this suggests that deeper theoretical and methodological differences lie at the root of the lack of consensus. Such disagreements are not likely to be resolved by additional fossil findings, but rather require critical re-evaluation of the evidence at hand and the application of novel techniques and perspectives. This is the premise and main goal of this volume. The major debates in Neanderthal research are re-examined with the use of innovative state-of-the art methods and exciting new theoretical and conceptual approaches. The diverse contributions presented here offer fresh insights and advances that move us closer to reaching a consensus.

The “packaging” of the diverse living world is untidy, with the result that there are no absolute criteria for recognizing in all contexts the bounded historical entities we call species. However, there is no doubt whatsoever that is as clear-cut a morphological entity as any in the hominid fossil record: one that is characterized by a whole host of cranial apomorphies. Further, a recent full-skeleton reconstruction further emphasizes just how different Neanderthal body structure was from that of , not simply in numerous anatomical details, but in the proportions of the thorax and its relation to the pelvic region. These bodily proportions would have given these extinct hominids a very distinctive appearance on the landscape, and enhance the likelihood that we are dealing here with a reproductively differentiated entity. Still, is not unique in all those features that distinguish it from . Many “Neanderthal” cranial features are shared with various middle Pleistocene European hominids, notably the Steinheim specimen and, to a lesser extent, the Sima de los Huesos hominids from Atapuerca. Indeed, it appears that, far from being an isolated phenomenon, formed part of a larger endemic European hominid clade. This clade seems to have existed contemporaneously in Europe with at least one other hominid lineage or clade, exemplified by the fossils from Mauer, Arago and Petralona.

The fossil cranium known as Saccopastore 1 was recovered in 1929 near Rome (Italy) in a gravel quarry that has been later replaced by building areas within the city. Its Neanderthal morphology was established early on, and detailed successive works described a combination of features in which traits that are recurrent among Würmian Neanderthals blend with those shared by Middle Pleistocene hominines. Recent computed analyses allowed the study of the endocranial structures through tomographic and digital approaches, and improved the ectocranial comparisons by using landmark-based multivariate techniques. This paper is aimed at synthesizing and describ-ing the current information available about the Saccopastore 1 cranial morphology, through an integration of past and present data. This specimen represents the best-preserved and most complete cranium in Europe among those dated to OIS 5. Its recognized Neanderthal identity suggests that the impact of the preceding cold stage (OIS 6, around 200—130 ka) was probably decisive in the definition of the Neanderthal phenotype, modifying the extent of genetic variation of previous European populations toward a more homogeneous gene pool.

The origin and evolutionary significance of the Neanderthals is still unresolved. Several basic questions about the biological processes determining the apomorphic morphology of this human group are still pending resolution. In this paper we present a general outline of the lines of research we are currently following in the exploration of Neanderthal anatomy. We focus our approach on three different aspects: (1) a methodological and theoretical component based on system theory; (2) specific morphological problems, such as the effects of body size and brain development on craniofacial shape in Neanderthals; and (3) the analysis of these aspects by geometric morphometric and paleohistological methods.

Being our closest living relatives, chimps and bonobos provide the best available comparative evidence to study the evolutionary split between our sister taxon — the Neanderthals — and ourselves. Here, we analyze craniofacial development in these taxa from birth to adulthood using geometric morphometric methods. In both and , ontogenetic trajectories of sister taxa differ by their length, position and/or direction in shape space, as well as in the relationship between cranial size and shape. Modern human and bonobo ontogenies represent “abridged” versions of Neanderthal and chimp spatiotemporal developmental patterns, respectively, where “shortening” of trajectories is likely to represent evolutionary novelty. When examined in detail, however, the Neanderthal-human and chimp-bonobo splits do not represent equivalent forms of evolutionary developmental diversification. Rather, it appears that each bifurcation is the result of a different unique evolutionary event, during which the ancestral mode of growth and development was modified in a taxon-specific manner.

In fossil hominins, phyletic diversification – the process by which ancestral species give rise to descendant ones – can only be inferred through analysis of patterns of morphological diversity displayed in the fossil record. These patterns are interpreted typically in terms of selection/adaptation and related to environmental change. From an organism-centered perspective, evolutionary modification of developmental processes is an equally important source of phyletic diversity. Here, we use model systems to simulate cranial growth and to explore how mutations in the “genes” of an “ancestral” morphogenetic system may affect “descendant” ontogenies and “adult” morphologies. Intriguingly, a model that assumes basic epigenetic interactions between developmental processes is capable of producing a wide variety of patterns of developmental modification, many of which are not foreseen in classic heterochronic theory. Also, small changes in developmental “genes” often have complex effects on patterns of ontogeny. With regard to the evolutionary split between Neanderthals and modern humans, these model considerations shall be an incentive to look at taxon-specific character complexes from the perspective of developmental as opposed to functional constraints.

The study of adaptation in Neanderthals is confounded by equifinality – the existence of multiple adaptive pathways to the same morphological end state – manifest as an inability to discriminate between equally likely selective agents behind a given trait. The capacious chests of Neanderthals serve as one example, possibly representing an adaptation either to cold or to high activity levels. While single features may be adaptive in multiple contexts, their relative adaptive value may vary greatly between contexts. Without means of evaluating competing adaptive arguments, we have little hope of identifying the primary selective agents that operated on Neanderthal body form. Bioenergetics provides a basis for quantifying the costs and benefits of various adaptive solutions to a given environmental challenge – thus providing potential for resolving issues of equifinality. Evaluating claims of cold-adapted morphology in Neanderthals involves determining the energetic costs of adhering to Bergmann's and Allen's rules. Skin surface area (SA) is the major determinant of basal metabolic rate (BMR) in mammals, thus estimating Neanderthal SA allows an estimate of the caloric cost of their coldadapted body form. Clinical equations exist for estimating SA from stature and mass, but these have never been tested on humans of extreme (i.e., “hyper-arctic”) body form. A half-size reconstruction of a male European Neanderthal was used to test the utility of these formulae: results indicate that they can be used confidently to predict Neanderthal SA. Based on Neanderthals for whom mass and stature can be reasonably estimated, mean SA is greater than that of Inuit of comparable stature, and suggests higher BMRs in Neanderthals than reported in previous studies.

The lifeways of Neanderthals remain poorly understood despite numerous hints from the archaeological record and from Neanderthal anatomy that their lifestyles may have differed substantially from early modern humans and from more recent populations. The distinctiveness, inefficiency, or primitiveness of Neanderthal lifestyles and patterns of activity play a central role in many adaptive scenarios that have been proposed to explain the eventual ascendancy of modern humans and the Neanderthals' demise. However, many recent studies of faunal remains accumulated by Neanderthals, stable isotope analyses of Neanderthal bones, and the energetic demands of their large body mass suggest that these archaic humans were equally efficient hunters as fully modern foragers in similar environments. This contradictory evidence inspired the present study. To gain new insights into Neanderthal behaviors we use a comparative approach, examining indices of residual bone strength and midshaft diaphyseal shapes of the humerus, femur, and tibia in several groups of Neanderthals (European and Near Eastern), early modern humans, and sixteen diverse groups of recent humans. The results indicate that Neanderthal limbs bear a close similarity to a fairly wide spectrum of more recent groups, especially those who practiced intensive forms of foraging within fairly limited territories. The Neanderthal pattern differs strikingly from those of Skhul-Qafzeh and Gravettian humans, but these early modern humans also differ substantially from the later, intensive foragers. These results are probably more indicative of the relative distribution of people to resources in the Mousterian than the relative behavioral of modern humans and Neanderthals.

Neanderthal hand remains are usually compared to those of recent humans because recent human samples are readily available. These comparisons demonstrate that Neanderthal hand morphologies are at or beyond the range of recent human samples for traits such as: expanded distal tuberosities, rugose musculotendinous attachment sites, dorsopalmarly flat metacarpal 1 bases, relatively short thumb proximal phalanges, more parasagittally oriented capitate metacarpal 2 facets, reduced metacarpal 3 styloid processes, radioulnarly flat metacarpal 5 bases, and large, projecting carpal tubercles. Functional interpretations suggest that Neanderthal hands are adapted primarily for power during manipulation.

Much debate has focused on the significance of the “modern” cultural elements found in European Late Middle Paleolithic (Châtelperronian, Uluzzian, and Szeletian) contexts. In light of evidence suggesting cultural interaction between the makers of these industries and the makers of the Aurignacian (presumably anatomically modern humans) it is imperative that the taxonomic affiliation of the hominins associated with these “transitional” industries be accurately identified. The fossil remains from the Châtelperronian levels (VIII-X) at the Grotte du Renne (Arcy-sur-Cure, France) comprise a series of isolated teeth, as well as a child’s temporal bone. While the temporal bone has been analyzed (and identified as having Neanderthal affinity), most of the 29 teeth from these levels have not been described. The Châtelperronian dental remains from the Grotte du Renne comprise both permanent and deciduous teeth. Fortunately, most are well preserved and relatively unworn. Simple dental dimensions are not par-ticularly helpful in attempts to differentiate between Neanderthals and anatomically modern humans. The dimen-sions of the postcanine teeth in these two groups overlap completely. However, Neanderthals are known to have larger anterior teeth (on average), especially relative to their postcanine tooth size. Not surprisingly, we find that the crown dimensions for the postcanine teeth from the Grotte du Renne fall within the ranges of both hominin groups.