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The abundant femoral assemblage of Homo naledi found in the Dinaledi Chamber provides a unique opportunity to test hypotheses regarding the taxonomy, locomotion, and loading patterns of this species. Here we describe neck and shaft cross-sectional structure of all the femoral fossils recovered in the Dinaledi Chamber and compare them to a broad sample of fossil hominins, recent humans, and extant apes. Cross-sectional geometric (CSG) properties from the femoral neck (base of neck and midneck) and diaphysis (subtrochanteric region and midshaft) were obtained through CT scans for H. naledi and through CT scans or from the literature for the comparative sample. The comparison of CSG properties of H. naledi and the comparative samples shows that H. naledi femoral neck is quite derived with low superoinferior cortical thickness ratio and high relative cortical area. The neck appears superoinferiorly elongated because of two bony pilasters on its superior surface. Homo naledi femoral shaft shows a relatively thick cortex compared to the other hominins. The subtrochanteric region of the diaphysis is mediolaterally elongated resembling early hominins while the midshaft is anteroposteriorly elongated, indicating high mobility levels. In term of diaphyseal robusticity, the H. naledi femur is more gracile that other hominins and most apes. Homo naledi shows a unique combination of characteristics in its femur that undoubtedly indicate a species committed to terrestrial bipedalism but with a unique loading pattern of the femur possibly consequence of the unique postcranial anatomy of the species.

The morphology and size of the Neandertal thorax is a subject of growing interest due to its link to general aspects of body size and shape, including physiological aspects related to bioenergetics and activity budgets. However, the number of well-preserved adult Neandertal costal remains is still low. The recent finding of new additional costal remains from the Regourdou 1 (R1) skeleton has rendered this skeleton as one of the most complete Neandertal costal skeletons with a minimum of 18 ribs represented, five of which are complete or virtually complete. Here we describe for the first time all the rib remains from R1 and compare them to a large modern Euroamerican male sample as well as to other published Neandertal individuals. The costal skeleton of this individual shows significant metric and morphological differences from our modern human male comparative sample. The perceived differences include: dorsoventrally large 1st and 2nd ribs, 3rd ribs with a very closed dorsal curvature and large maximum diameters at the posterior angle, a large tubercle-iliocostal line distance in the 4th rib, thick shafts at the dorsal end of its 6th ribs, thick mid-shafts of the 8th ribs, large articular tubercles at the 9th ribs, and thick shafts of the 11th and 12th ribs. Here we also describe a new mesosternal fragment: the left lateral half of sternebral segments 4 and 5. This portion reveals that the mesosternum of R1 had a sternal foramen in its inferiormost preserved sternal segment and supports previous estimation of the total length of this mesosternum. The new costal remains from R1 support the view that Neandertals, when compared with modern humans, show a significantly different thorax, consistent with differences found in other anatomical regions such as the vertebral column and pelvis.

This paper describes the 108 femoral, patellar, tibial, and fibular elements of a new species of Homo (Homo naledi) discovered in the Dinaledi chamber of the Rising Star cave system in South Africa. Homo naledi possesses a mosaic of primitive, derived, and unique traits functionally indicative of a bipedal hominin adapted for long distance walking and possibly running. Traits shared with australopiths include an anteroposteriorly compressed femoral neck, a mediolaterally compressed tibia, and a relatively circular fibular neck. Traits shared with Homo include a well-marked linea aspera, anteroposteriorly thick patellae, relatively long tibiae, and gracile fibulae with laterally oriented lateral malleoli. Unique features include the presence of two pillars on the superior aspect of the femoral neck and a tubercular distal insertion of the pes anserinus on the tibia. The mosaic morphology of the H. naledi thigh and leg appears most consistent with a species intermediate between Australopithecus spp. and Homo erectus and, accordingly, may offer insight into the nature of the earliest members of genus Homo. These fossils also expand the morphological diversity of the Homo lower limb, perhaps indicative of locomotor diversity in our genus.

International audience; The calcium isotopic composition (δ44/42Ca) of bone and tooth enamel can be used for dietary reconstructions of extant and extinct mammals. In natural conditions, the δ44/42Ca value of bone and teeth varies according to dietary intake with a constant isotopic offset of about −0.6‰. Owing to the poor conservation of collagen, carbon (C), and nitrogen (N) isotopic compositions of the Regourdou Mousterian site (MIS 5, Dordogne, France) previously failed to provide any paleodietary information. Therefore, to reconstruct the trophic chain, we have measured calcium (Ca) isotopes from fossil bone samples of the fauna from the Regourdou site, as well as from three bone samples of the Regourdou 1 Neandertal specimen. The results show a taxon-dependent patterning of the Ca isotopic compositions: herbivores generally have higher δ44/42Ca values than carnivores. All the δ44/42Ca values of Regourdou 1 are low (

Regourdou is a well-known Middle Paleolithic site which has yielded the fossil remains of a minimum of two Neandertal individuals. The first individual (Regourdou 1) is represented by a partial skeleton while the second one is represented by a calcaneus. The foot remains of Regourdou 1 have been used in a number of comparative studies, but to date a full description and comparison of all the foot remains from the Regourdou 1 Neandertal, coming from the old excavations and from the recent reanalysis of the faunal remains, does not exist. Here, we describe and comparatively assess the Regourdou 1 tarsals, metatarsals and phalanges. They display traits observed in other Neandertal feet, which are different from some traits of the Sima de los Huesos (Atapuerca) hominins and of Middle Paleolithic, Upper Paleolithic and recent modern humans. These Neandertal features are: a rectangular talar trochlea with a large lateral malleolar facet, a broad talar head, a broad calcaneus with a projecting sustentaculum tali, a wide and wedged navicular with a projecting medial tubercle, large and wide bases of the lateral metatarsals, and mediolaterally expanded and robust phalanges that also show hallux valgus in a strongly built hallux.

17 pages; International audience; The understanding of Neanderthal societies, both with regard to their funerary behaviors and their subsistence activities, is hotly debated. Old excavations and a lack of taphonomic context are often factors that limit our ability to address these questions. To better appreciate the exact nature of what is potentially the oldest burial in Western Europe, Regourdou (Montignac-sur-Vézère, Dordogne), and to better understand the taphonomy of this site excavated more than 50 years ago, we report in this contribution a study of the most abundant animals throughout its stratigraphy: the European rabbit (Oryctolagus cuniculus). In addition to questions surrounding the potential bioturbation of the site's stratigraphy, analysis of the Regourdou rabbits could provide new information on Neandertal subsistence behavior. The mortality profile, skeletal-part representation, breakage patterns, surface modification, and comparison with modern reference collections supports the hypothesis that the Regourdou rabbit remains were primarily accumulated due to natural (attritional) mortality. Radiocarbon dates performed directly on the rabbit remains give ages ranging within the second half of Marine Isotope Stage 3, notably younger than the regional Mousterian period. We posit that rabbits dug their burrows within Regourdou's sedimentological filling, likely inhabiting the site after it was filled. The impact of rabbit activity now brings into question both the reliability of the archaeostratigraphy of the site and the paleoenvironmental reconstructions previously proposed for it, and suggests rabbits may have played a role in the distribution of the Neandertal skeletal remains.

Homo erectus and later humans have enlarged body sizes, reduced sexual dimorphism, elongated lower limbs, and increased encephalization compared to Australopithecus , together suggesting a distinct ecological pattern. The mosaic expression of such features in early Homo , including Homo habilis , Homo rudolfensis , and some early H. erectus , suggests that these traits do not constitute an integrated package. We examined the evidence for body mass, stature, limb proportions, body size and dental size dimorphism, and absolute and relative brain size in Homo naledi as represented in the Dinaledi Chamber sample. H. naledi stature and body mass are low compared to reported values for H. erectus , with the exception of some of the smaller bodied Dmanisi H. erectus specimens, and overlap with larger Australopithecus and early Homo estimates . H. naledi endocranial volumes (465–560 cc) and estimates of encephalization quotient are also similar to Australopithecus and low compared to all Homo specimens, with the exception of Homo floresiensis (LB1) and the smallest Dmanisi H. erectus specimen (D4500). Unlike Australopithecus , but similar to derived members of genus Homo , the Dinaledi assemblage of H. naledi exhibits both low levels of body mass and dental size variation, with an estimated body mass index of sexual dimorphism less than 20%, and appears to have an elongated lower limb. Thus, the H. naledi bauplan combines features not typically seen in Homo species (e.g., small brains and bodies) with those characteristic of H. erectus and more recent Homo species (e.g., reduced mass dimorphism, elongated lower limb).

In humans, a notch marking the posterior attachment of the lateral meniscus is often visible on the posterior, lateral plateau of the tibia, adjacent to the intercondylar eminence. In theory, the presence or absence of this notch in dry bone can be used to differentiate the fossil remains of Australopithecus from those of the genus Homo. In a small-scale study, however, we found examples of modern human tibiae that appear not to have such a notch. In other cases, the morphology of the surrounding bone made it difficult to determine whether or not the notch was present. Although based on a small sample, this study questions: 1) the theoretical postulate that the lateral meniscal notch can be used to differentiate between hominin taxa, and 2) the practical reliability of determining the absence or presence of the notch in fossil remains.

Bivariate femoral length allometry in recent humans, Pan, and Gorilla is investigated with special reference to the diminutive Liang Bua (LB) 1 specimen (the holotype of Homo floresiensis) and six early Pleistocene femora referred to the genus Homo. Relative to predicted body mass, Pan and Gorilla femora show strong negative length allometry while recent human femora evince isometry to positive allometry, depending on sample composition and line-fitting technique employed. The allometric trajectories of Pan and Homo show convergence near the small body size range of LB 1, such that LB 1 manifests a low percentage deviation (dyx of Smith [1980] ) from the Pan allometric trajectory and falls well within the 95% confidence limits around the Pan individuals (but also outside the 95% confidence limits for recent Homo). In contrast, the six early Pleistocene Homo femora, belonging to larger individuals, show much greater dyx values from both Pan and Gorilla and fall well above the 95% confidence limits for these taxa. All but one of these Pleistocene Homo specimens falls within the 95% confidence limits of the recent human sample. Similar results are obtained when femoral length is regressed on femoral head diameter in unlogged bivariate space. Regardless of the ultimate taxonomic status of LB 1, these findings are consistent with a prediction made by us ( Franciscus and Holliday, 1992 ) that hominins in the small body size range of A.L. 288-1 (“Lucy”), including members of the genus Homo, will tend to possess short, ape-like lower limbs as a function of body size scaling.

Long-term trends in robusticity of lower limb bones in the genus Homo through the Pleistocene until the present have been proposed, which have been interpreted as a consequence of decreasing levels of mobility and activity patterns, changes in lifestyle, and environmental factors. There has also long been evidence that skeletal strength increases over an individual's lifespan. This increase is caused by continuous bone remodeling that optimizes the structure of a bone to resist mechanical loadings and creates a balance between endosteal resorption and subperiosteal apposition. However, none of the previous studies of temporal trends in robusticity has considered both processes and analyzed how individual age-related robusticity might influence higher-level temporal trends. This paper therefore explores temporal trends in robusticity of lower limb long bones within the genus Homo and considers how individual ages-at-death can confound published evolutionary trends, given the fact that some aspects of relative bone strength tend to increase over individual lifespans. Cross-sectional diaphyseal properties of the midshaft and proximal femur and midshaft tibia of Pleistocene and early Holocene individuals, together with data on age-at-death are used to analyze changes in relative bone strength relative to individuals' ages and evolutionary time. The results show increasing bone strength in adulthood until the fourth decade and then a slight decrease, an observation that conforms to previously published results on recent human populations. However, no significant impact of age-at-death on the trends along an evolutionary trajectory has been detected. The evolutionary trends in femoral and tibial relative strength can be described as fluctuating, probably as a consequence of changing mobility patterns, environmentally and technologically influenced behaviors, and demographic processes. The differences between evolutionary trends published in several studies are explained primarily as a result of different ways of standardizing cross-sectional parameters for size, and differences in sample composition.

The robust diaphyses of Pleistocene hominins are said to indicate higher activity levels in these prehistoric humans than among people today. Thus, it could be argued that the prediction of body mass from fossil lower limb diaphyseal cortical area (CA) using recent human regressions might lead to erroneously high body mass estimates. This study uses three body mass prediction formulae based on the following features: reconstructed femoral 80% (subtrochanteric) CA, femoral head diameter (FH), and bi-iliac breadth and stature (BIB-St) among European Early and Late Upper Paleolithic (EUP and LUP) and recent humans from Africa and Europe. All three methods produce similar body mass estimates for all groups studied, including recent humans. Gleaning behavioral differences from these data is more difficult, as no significant differences in CA were found among the fossil and recent Europeans. It has been suggested that the EUP had less robust diaphyses than their LUP counterparts. However, here this result is only obtained when CA is size-standardized to femoral length(3) (Ruff et al., 1993, Am. J. phys. Anthrop.91, 21-53 Trinkaus et al., 1998, in Neandertals and Modern Humans in Western Asia, pp.391-404, New York: Plenum). This should not be interpreted as evidence for lower activity levels in the EUP, but rather as an artefact of standardization, for as Wolpoff (1999), Am. J. phys. Anthrop.109, 416-423 points out, these standardized variables are extremely sensitive to limb length differences, and the EUP have longer limbs than their LUP counterparts. With this in mind, these data do not support a pattern of behavioral differences between EUP and LUP humans, and therefore more sensitive measures than CA may be required to detect such differences.

European Neandertals employed a complex set of physiological cold defenses, homologous to those seen in contemporary humans and nonhuman primates. While Neandertal morphological patterns, such as foreshortened extremities and low relative surface-area, may have explained some of the variance in cold resistance, it is suggested the adaptive package was strongly dependent on a rich array of physiological defenses. A summary of the environmental cold conditions in which the Neandertals lived is presented, and a comparative ethnographic model from Tierra del Fuego is used. Muscle and subcutaneous fat are excellent “passive” insulators. Neandertals were quite muscular, but it is unlikely that they could maintain enough superficial body fat to offer much cold protection. A major, high-energy metabolic adaptation facilitated by modest amounts of highly thermogenic brown adipose tissue (BAT) is proposed. In addition, Neandertals would have been protected by general mammalian cold defenses based on systemic vasoconstriction and intensified by acclimatization, aerobic fitness, and localized cold-induced vasodilation. However, these defenses are energetically expensive. Based on contemporary data from circumpolar peoples, it is estimated that Neandertals required 3,360 to 4,480 kcal per day to support strenuous winter foraging and cold resistance costs. Several specific genetic cold adaptations are also proposed—heat shock protein (actually, stress shock protein), an ACP*1 locus somatic growth factor, and a specialized calcium metabolism not as yet understood. Am. J. Hum. Biol. 14:566–583, 2002. © 2002 Wiley-Liss, Inc.

Analyse critique de l'approche de Groves concernant les affinites morphologiques de l'ulna humaine du niveau Middle Stone Age de Klasies River Mouth. Les AA considerent l'analyse variee canonique (CVA) preferable a l'analyse par composantes principales (PCA)

Body proportions covary with climate, apparently as the result of climatic selection. Ontogenetic research and migrant studies have demonstrated that body proportions are largely genetically controlled and are under low selective rates; thus studies of body form can provide evidence for evolutionarily short-term dispersals and/or gene flow. Following these observations, competing models of modern human origins yield different predictions concerning body proportion shifts in Late Pleistocene Europe. Replacement predicts that the earliest modern Europeans will possess “tropical” body proportions (assuming Africa is the center of origin), while Regional Continuity permits only minor shifts in body shape, due to climatic change and/or improved cultural buffering. This study tests these predictions via analyses of osteometric data reflective of trunk height and breadth, limb proportions and relative body mass for samples of Early Upper Paleolithic (EUP), Late Upper Paleolithic (LUP) and Mesolithic (MES) humans and 13 recent African and European populations. Results reveal a clear tendency for the EUP sample to cluster with recent Africans, while LUP and MES samples cluster with recent Europeans. These results refute the hypothesis of local continuity in Europe, and are consistent with an interpretation of elevated gene flow (and population dispersal?) from Africa, followed by subsequent climatic adaptation to colder conditions. These data do not, however, preclude the possibility of some (albeit small) contribution of genes from Neandertals to succeeding populations, as is postulated in Brauer’s “Afro-European Sapiens” model.

The Middle Stone Age (MSA) asociated hominids from Klasies River Mouth (KRM) have taken on a key role in debate about the origins of modern humans, with their craniofacial remains seen as either representing the earliest well-dated modern humans in southern Africa or orthognathic late archaic humans. Diagnostic postcranial remains from Klasies are few, but one specimen—a proximal right ulna from the lower SAS member—is useful for assessing the morphological affinities of these hominids. Canonical variates analysis using 14 proximal ulnar dimensions and comparative data from European, west Asian and African archaic humans, and Levantine Mousterian, European Upper Paleolithic, African Epipaleolithic and diverse recent modern human samples (many of recent African descent) were employed to assess the morphological affinities of this specimen. Results suggest an archaic total morphological pattern for the Klasies ulna. Analysis of diaphyseal cross-sectional geometry reveals an ulnar shaft with relatively thick cortical bone, but the specimen cannot be readily distinguished from Neandertals or early anatomically modern humans on the basis of shaft cross-sectional properties. If the isolated ulna from Klasies is indicative of the general postcranial morphology of these hominids, then the MSA-associated humans from KRM may not be as modern as has been claimed from the craniofacial material. It is possible also that the skeletal material from KRM reflects mosaic evolution—retention of archaic postcranial characteristics, perhaps indicating retention of archaic habitual behavior patterns, in hominids that were becoming craniofacially modern.

There are two competing hypotheses to explain the relatively long lower limbs of the earliest modern Europeans. The first follows from Allen's (1877) rule and posits that the long legs are indicative of gene flow from warmer regions at the time of the archaic/modern Homo sapiens transition. The second maintains that the long lower limbs are an adaptive response to selection for locomotor efficiency. This paper tests predictions derived from these two competing hypotheses using anthropometric, residential mobility and climatic data for a sample of 19 recent hunter-gatherer groups. For this sample, there is no relationship between relative lower limb length (as reflected in relative sitting height) and residential mobility. Consequently, the mobility hypothesis can be rejected. However, a significant relationship between climate and relative lower limb length could not be rejected. With regard to Later Pleistocene human evolution, these results are interpreted as evidence for significant gene flow from tropical regions associated with the first appearance of modern humans in Europe.

Among recent humans brachial and crural indices are positively correlated with mean annual temperature, such that high indices are found in tropical groups. However, despite inhabiting glacial Europe, the Upper Paleolithic Europeans possessed high indices, prompting Trinkaus (1981) to argue for gene flow from warmer regions associated with modern human emergence in Europe. In contrast, Frayeret al. (1993) point out that Late Upper Paleolithic and Mesolithic Europeans shouldnotexhibit tropically-adapted limb proportions, since, even assuming replacement, their ancestors had experienced cold stress in glacial Europe for at least 12 millennia. This study investigates three questions tied to the brachial and crural indices among Late Pleistocene and recent humans. First, which limb segments (either proximal or distal) are primarily responsible for variation in brachial and crural indices? Second, are these indices reflective ofoveralllimb elongation? And finally, do the Late Upper Paleolithic and Mesolithic Europeans retain relatively and/or absolutely long limbs? Results indicate that in the lower limb, the distal limb segment contributes most of the variability to intralimb proportions, while in the upper limb the proximal and distal limb segments appear to be equally variable. Additionally, brachial and crural indices do not appear to be a good measure of overall limb length, and thus, while the Late Upper Paleolithic and Mesolithic humans have significantly higher (i.e., tropically-adapted) brachial and crural indices than do recent Europeans, they also have shorter (i.e., cold-adapted) limbs. The somewhat paradoxical retention of “tropical” indices in the context of more “cold-adapted” limb length is best explained as evidence for Replacement in the European Late Pleistocene, followed by gradual cold adaptation in glacial Europe.