154 research outputs found
Hand to mouth in a Neandertal : right-handedness in regourdou 1
We describe and analyze a Neandertal postcranial skeleton and dentition, which together show unambiguous signs of right-handedness. Asymmetries between the left and right upper arm in Regourdou 1 were identified nearly 20 years ago, then confirmed by more detailed analyses of the inner bone structure for the clavicle, humerus, radius and ulna. The total pattern of all bones in the shoulder and arm reveals that Regourdou 1 was a right-hander. Confirmatory evidence comes from the mandibular incisors, which display a distinct pattern of right oblique scratches, typical of right-handed manipulations performed at the front of the mouth. Regourdou's right handedness is consistent with the strong pattern of manual lateralization in Neandertals and further confirms a modern pattern of left brain dominance, presumably signally linguistic competence. These observations along with cultural, genetic and morphological evidence indicate language competence in Neandertals and their European precursors
Skeletal remains from punic carthage do not support systematic sacrifice of infants
Two types of cemeteries occur at Punic Carthage and other Carthaginian settlements: one centrally situated housing the remains of older children through adults, and another at the periphery of the settlement (the "Tophet") yielding small urns containing the cremated skeletal remains of very young animals and humans, sometimes comingled. Although the absence of the youngest humans at the primary cemeteries is unusual and worthy of discussion, debate has focused on the significance of Tophets, especially at Carthage, as burial grounds for the young. One interpretation, based on two supposed eye-witness reports of large-scale Carthaginian infant sacrifice [Kleitarchos (3rd c. BCE) and Diodorus Siculus (1st c. BCE)], a particular translation of inscriptions on some burial monuments, and the argument that if the animals had been sacrificed so too were the humans, is that Tophets represent burial grounds reserved for sacrificial victims. An alternative hypothesis acknowledges that while the Carthaginians may have occasionally sacrificed humans, as did their contemporaries, the extreme youth of Tophet individuals suggests these cemeteries were not only for the sacrificed, but also for the very young, however they died. Here we present the first rigorous analysis of the largest sample of cremated human skeletal remains (348 burial urns, N = 540 individuals) from the Carthaginian Tophet based on tooth formation, enamel histology, cranial and postcranial metrics, and the potential effects of heat-induced bone shrinkage. Most of the sample fell within the period prenatal to 5-to-6 postnatal months, with a significant presence of prenates. Rather than indicating sacrifice as the agent of death, this age distribution is consistent with modern-day data on perinatal mortality, which at Carthage would also have been exacerbated by numerous diseases common in other major cities, such as Rome and Pompeii. Our diverse approaches to analyzing the cremated human remains from Carthage strongly support the conclusion that Tophets were cemeteries for those who died shortly before or after birth, regardless of the cause. © 2010 Schwartz et al
Hand to Mouth in a Neandertal: Right-Handedness in Regourdou 1
We describe and analyze a Neandertal postcranial skeleton and dentition, which together show unambiguous signs of right-handedness. Asymmetries between the left and right upper arm in Regourdou 1 were identified nearly 20 years ago, then confirmed by more detailed analyses of the inner bone structure for the clavicle, humerus, radius and ulna. The total pattern of all bones in the shoulder and arm reveals that Regourdou 1 was a right-hander. Confirmatory evidence comes from the mandibular incisors, which display a distinct pattern of right oblique scratches, typical of right-handed manipulations performed at the front of the mouth. Regourdou's right handedness is consistent with the strong pattern of manual lateralization in Neandertals and further confirms a modern pattern of left brain dominance, presumably signally linguistic competence. These observations along with cultural, genetic and morphological evidence indicate language competence in Neandertals and their European precursors.The TNT European project, French CNRS, RĂ©gion Poitou-Charentes, Nespos Society, and Leakey Foundation provided financial support
The Neandertal (Krapina and Regourdou 1), fossil modern human (Chancelade 1) and extant human patella: an insight from inside
Evolutionary endostructural patterns of the cortical and cancellous tissues of the postcranial skeleton are commonly investigated for inferring functional behaviours in extinct hominin taxa and past human populations. Information on the endostructural arrangement of the patellar bone has the potential of revealing individual- and/or taxon-specific aspects of the knee biomechanics. However, evidence on its inner conformation extracted from human fossil specimens is nearly non-existent. The present pilot study aims at characterising the endostructural pattern of two Neandertal (from Krapina, Croatia, and Regourdou, France) and one anatomically modern fossil human (from Chancelade, France) adult patellae and to compare their signal with the recent human condition. In the context of the gracilisation trend of the human skeleton occurred from the late Pleistocene, we expect (i) the two Neandertal patellae showing a higher amount of cortical bone compared to the fossil modern and the recent human conditions, (ii) the fossil modern patella showing a higher amount of cortical bone compared to the comparative sample, (iii) the cancellous network being relatively homogeneous between the two Neandertal individuals but distinguishable from that of the fossil modern human representative and of the comparative sample, and that (iv) the structural organisation revealed by the fossil modern patella is distinguishable from the recent human condition. For assessing the endostructural organisation of the selected patellae, we used non-invasive techniques of high resolution virtual imaging. The results do not support the first hypothesis, as marked differences have been found between the two Neandertal specimens. The second hypothesis is supported for the anterior surface, but not for the posterior surface. The third hypothesis is supported for the superior and the lateral regions of the patellar bone but for the inferior and medial portions. Finally, the fourth hypothesis is supported, but the cancellous organisation of the two Neandertal representatives is closer to the extant human pattern than to the Magdalenian specimen. Despite the generalised lack of comparable information from the human fossil record, we consider the present results of potential interest for future research of paleobiomechanical, paleobiological, and perhaps taxonomic interest, on the evolutionary structure of the human knee joint.Les patrons dâĂ©volution de lâendostructure des tissus cortical et trabĂ©culaire du squelette postcrĂąnien sont communĂ©ment analysĂ©s pour reconstruire les activitĂ©s fonctionnelles des homininĂ©s fossiles et des populations humaines anciennes. Les informations sur lâarrangement endostructural de la patella ont le potentiel de dĂ©celer des aspects de la biomĂ©canique du genou spĂ©cifiques Ă lâindividu ou caractĂ©ristiques dâune espĂšce. Cependant, les tĂ©moins de la conformation interne extraits de spĂ©cimens humains fossiles sont quasi-inexistants. Cette Ă©tude pilote a pour objectif de caractĂ©riser le patron de lâendostructure de deux patellae nĂ©andertaliennes (de Krapina, Croatie, et Regourdou, France) et dâune patella dâun humain moderne fossile (Chancelade, France) et de le comparer Ă la condition humaine rĂ©cente. Dans le contexte dâun processus de gracilisation du squelette humain de la fin du PlĂ©istocĂšne, nous formulons les hypothĂšses suivantes: (i) les deux patellae nĂ©andertaliennes prĂ©sentent un cortex plus Ă©pais par rapport aux conditions moderne fossile et rĂ©cente, (ii) la patella moderne fossile prĂ©sente un cortex plus Ă©pais que mesurĂ© dans lâĂ©chantillon comparatif, (iii) le rĂ©seau trabĂ©culaire est relativement homogĂšne entre les NĂ©andertaliens mais distinct de celui du fossile moderne et de lâĂ©chantillon comparatif et (iv) lâorganisation structurale de la patella moderne fossile est distincte de la condition humaine rĂ©cente. Pour analyser lâendostructure des patellae sĂ©lectionnĂ©es nous avons utilisĂ© des techniques non-invasives dâimagerie virtuelle Ă haute rĂ©solution. Les rĂ©sultats ne soutiennent pas la premiĂšre hypothĂšse car des diffĂ©rences importantes ont Ă©tĂ© montrĂ©es entre les deux spĂ©cimens nĂ©andertaliens. La seconde hypothĂšse est vĂ©rifiĂ©e pour la surface antĂ©rieure mais pas pour celle postĂ©rieure. La troisiĂšme hypothĂšse est vĂ©rifiĂ©e pour les rĂ©gions supĂ©rieure et latĂ©rale de la patella mais pas pour celles infĂ©rieure et mĂ©diale. Finalement, la quatriĂšme hypothĂšse est vĂ©rifiĂ©e mais lâorganisation trabĂ©culaire des deux NĂ©andertaliens est plus proche de la condition humaine rĂ©cente que celle du spĂ©cimen magdalĂ©nien. MalgrĂ© le manque gĂ©nĂ©ralisĂ© dâinformations comparatives issues du registre humain fossile, nous estimons que les rĂ©sultats de cette Ă©tude pilote ont un intĂ©rĂȘt potentiel pour des recherches futures dâintĂ©rĂȘt palĂ©obiomĂ©canique, palĂ©obiologique et, peut-ĂȘtre, taxinomique sur lâĂ©volution de la structure de lâarticulation du genou humain
The SKX 1084 hominin patella from Swartkrans Member 2, South Africa: An integrated analysis of its outer morphology and inner structure
SKX 1084 is an isolated partial patella from Swartkrans Member 2, South Africa, attributed to a small-bodied Paranthropus robustus. This study provides complementary information on its outer conformation and, for the first time for a fossil hominin patella, documents its inner structure in the perspective of adding biomechanically-related evidence to clarify its identity. We used X-ray micro-tomography to investigate SKX 1084 and to extract homologous information from a sample of 12 recent human, one Neanderthal, and two adult Pan, patellae. We used geometric morphometrics to compare the outer equatorial contours. In SKX 1084, we identified two cancellous bony spots suitable for textural assessment (trabecular bone volume fraction, trabecular thickness, degree of anisotropy), and two related virtual slices for measuring the maximum cortico-trabecular thickness (CTT) of the articular surface. SKX 1084 shows a more complex articular shape than that for Pan, but still simpler than typical in Homo sapiens. At all sites, its CTT is thinner compared to Pan and approaches the condition in humans. This is also true for the expanded volume of the cancellous network. However, at both investigated spots, SKX 1084 is systematically intermediate between Homo and Pan for trabecular bone volume fraction and trabecular thickness, a pattern already shown in previous analyses on other Paranthropus postcranial remains. In the absence of any structural signal from patellae unambiguously sampling Paranthropus, as well as of comparable evidence extracted from specimens representing early Homo, our results do not allow rejection of the original taxonomic attribution of SKX 1084
Exploring Hominin and Non-hominin Primate Dental Fossil Remains with Neutron Microtomography
Fossil dental remains are an archive of unique information for paleobiological studies. Computed microtomography based on X-ray microfocus sources (X-ÎŒCT) and Synchrotron Radiation (SR-ÎŒCT) allow subtle quantification at the micron and sub-micron scale of the meso- and microstructural signature imprinted in the mineralized tissues, such as enamel and dentine, through high-resolution virtual histology . Nonetheless, depending on the degree of alterations undergone during fossilization, X-ray analyses of tooth tissues do not always provide distinct imaging contrasts, thus preventing the extraction of essential morphological and anatomical details. We illustrate here by three examples the successful application of neutron microtomography (n-ÎŒCT) in cases where X-rays have previously failed to deliver contrasts between dental tissues of fossilized specimen
The TM 1517 odontoskeletal assemblage from Kromdraai B, South Africa, and the maturational pattern of Paranthropus robustus
The holotype of Paranthropus robustus was discovered by R. Broom in 1938 in an outcrop of bone breccia at the cave site of Kromdraai B, in Gauteng, South Africa [1]. It consists of the left half of a cranium (TM 1517a) and an associated right mandibular corpus (TM 1517b), both bearing teeth, and of seven isolated teeth (a LLP3, a LLP4 and the series URP3-M3 labelled as TM 1517c). A few weeks later, close to the block containing the cranial remains, Broom identified four postcranial elements: the distal end of a right humerus (TM 1517g), the partial proximal end of a right ulna (TM 1517e), and two toe bones (TM 1517k and TM 1517o), all at the time attributed to the same young individual represented by the cranial remains. However, the distal foot phalanx TM 1517o was subsequently attributed to a baboon. While the holotype has been variously referred to as a 'young female', a 'young adult', as 'probably male and immature', or as a 'late adolescent', it certainly represents a dentally immature individual. Since these early descriptions, no study has explored the possibility that the associated postcranial remains preserve evidence of active bone growth or recent epiphyseal closure. Clearly, however, such information would either strengthen, or challenge the idea that the craniodental and postcranial remains belong to a single P. robustus individual and, importantly, might provide the first evidence about the odontoskeletal maturational pattern of this fossil taxon. Accordingly, we performed a micro-XCT-based study aimed at characterising the inner structure of the distal humerus TM 1517g, the proximal ulna TM 1517e and the distal hallucial phalanx TM 1517k. Our 2-3D analyses show that the distal humerus was likely completely fused, while the proximal ulna still displays a faint remnant of fusion, and the distal hallucial phalanx shows evidence of still growing bone. These findings, as well as the observation that the distal humerus and the proximal ulna fit anatomically and morpho-dimensionally [2], provide support for the original attribution of the cranial and the three postcranial remains from Kromdraai B to a single individual representing the P. robustus type specimen. Using extant human dental standards, the age at death estimate of TM 1517 is of 16.5±3 years if based on the LM2 (not fully closed distal apices) and LM3 root developmental stages (root formation stage between half and three-quarters completed). The skeletal age ranges between 14 and 18 years, for a male, and between 11 and 15 years, for a female individual. When a chimpanzee dental growth pattern is considered, TM 1517 fits the c. 10.5 years 'older juvenile' group [3], while chimpanzee skeletal maturity standards place it between 7.95 and 13.5 years. Interestingly, in humans fusion of the distal hallucial phalanx commonly slightly precedes that of the distal humerus. However, a sequence of distal humerus-distal hallucial phalanx-proximal ulna fusion, as displayed by TM 1517, is usually observed in Pan. Taken together, this new evidence for TM 1517 more closely resembles the chimpanzee condition for maturational patterning. This finding is broadly in line with the evidence observed for Australopithecus sediba [4] and Homo erectus from Nariokotome [5]. Nevertheless, since P. robustus seems characterised by sexual bimaturism (with the males experiencing prolonged growth), the uncertain sex attribution of TM 1517 still represents a limiting interpretative factor
Inner structural organization of the distal humerus in Paranthropus and Homo
The taxonomic attribution of isolated hominin distal humeri has been a matter of uncertainty and disagreement notwithstanding their relative abundance in the fossil record. Four taxonomically-based morphotypes, respectively representing P. boisei, P. robustus, non-erectus early Homo and H. erectus, have been identified based on the cross-sectional outer shape variation of an assemblage of Plio-Pleistocene eastern and southern African specimens (Lague, 2015). However, the existence of possible differences between Paranthropus and Homo in the inner structural organisation at this skeletal site remains unexplored. We used noninvasive imaging techniques to tentatively characterize the endostructural organization of five early Pleistocene distal humeri from South Africa (TM 1517g, SK 24600, SKX 10924, SKX 34805) and Ethiopia (Gombore IB), which have been variably attributed to Paranthropus or Homo. While the investigated specimens reveal diverse degrees of inner preservation related to their taphonomic and diagenetic history, in all but SK 24600 from Swartkrans we could comparatively assess some geometric properties at the most distal cross-sectional level (%CA, Ix/Iy, Imax/Imin) and quantify cortical bone thickness topographic variation across the preserved shaft portions by means of a 2-3D Relative Cortical Thickness index. Whenever possible, we also provided details about the site-specific organization of the cancellous network and measured the same parameters in a comparative sample of twelve adult extant humans. For most features, our results indicate two main patterns: the first includes the specimens TM 1517g, SKX 10924 and SKX 34805, while the second endostructural morphotype sets apart the robust Homo aff. erectus Gombore IB specimen from Melka Kunture, which more closely resembles the condition displayed by our comparative human sample. Notably, marked differences in the amount and pattern of proximodistal cortical bone distribution have been detected between Gombore IB and SKX 34805 from Swartkrans. Given its discordant outer and inner signatures, we conclude that the taxonomic status of SKX 34805 deserves further investigations
Is the deciduous/permanent molar enamel thickness ratio a taxon-specific indicator in extant and extinct hominids?
In Primates, enamel thickness variation stems from an evolutionary interplay between functional/adaptive constraints (ecology) and the strict control mechanisms of the morphogenetic program. Most studies on primate enamel thickness have primarily considered the permanent teeth, while the extent of covariation in tooth enamel thickness distribution between deciduous and permanent counterparts remains poorly investigated. In this test study on nine extant and fossil hominids we investigated the degree of covariation in enamel proportions between 25 pairs of mandibular dm2 and M1 by a so-called âlateral enamel thickness diphyodontic indexâ. The results did not provide an unambiguous picture, but rather suggest complex patterns likely resulting from the influence of many interactive factors. Future research should test the congruence of the âdiphyodontic signalâ between the anterior and the postcanine dentition, as well as between enamel and the enamel-dentine junction topography
Early Pliocene Hominid Tooth from Galili, Somali Region, Ethiopia
A fossil hominid tooth was discovered during survey at Galili, Somali region, Ethiopia.
The geological and faunal context indicate an Early Pliocene age. The specimen
(GLL 33) consists of an almost complete lower right third molar likely representing a
male individual of advanced age-at-death. Its comparative metrical, morphological
and (micro)structural analysis (supported by a microtomographic record) suggests a
tentative taxonomic allocation to Australopithecus cf. A. afarensis
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