1,721,274 research outputs found
Aux origines d'homo sapiens, sous la dir. de Jean- Jacques Hublin et Anne-Marie Tillier (Paris, PUF, 1991)
No full textAux origines d'homo sapiens, sous la dir. de Jean- Jacques Hublin et Anne-Marie Tillier (Paris, PUF, 1991). In: Revue d'histoire des sciences, tome 46, n°1, 1993. pp. 107-108
Aux origines d'homo sapiens, sous la dir. de Jean- Jacques Hublin et Anne-Marie Tillier (Paris, PUF, 1991)
No full textAux origines d'homo sapiens, sous la dir. de Jean- Jacques Hublin et Anne-Marie Tillier (Paris, PUF, 1991). In: Revue d'histoire des sciences, tome 46, n°1, 1993. pp. 107-108
Grisse A. (2006). Früh-und mittelkupferzeitliche Streitäxe in westlichen Mitteleuropa suivi de "À propos d’une critique: réponse à Valery Zeitoun" de Olivier Dutour, Jean-Jacques Hublin, Bernard Vandermeersch
No full textPétrequin Pierre. Grisse A. (2006). Früh-und mittelkupferzeitliche Streitäxe in westlichen Mitteleuropa suivi de "À propos d’une critique: réponse à Valery Zeitoun" de Olivier Dutour, Jean-Jacques Hublin, Bernard Vandermeersch. In: Bulletin de la Société préhistorique française, tome 103, n°4, 2006. pp. 807-808
Allometry, merism, and tooth shape of the upper deciduous M2 and permanent M1
No full textThe aims of this study were to investigate
the effect of allometry on the shape of dm2 and M1 crown
outlines and to examine whether the trajectory and magnitude
of scaling are shared between species. The sample
included 160 recent Homo sapiens, 28 Upper Paleolithic H.
sapiens, 10 early H. sapiens, and 33 H. neanderthalensis
(Neandertal) individuals. Of these, 97 were dm2/M1 pairs
from the same individuals. A two-block partial least
squares analysis of paired individuals revealed a significant
correlation in crown shape between dm2 and M1. A
principal component analysis confirmed that Neandertal
and H. sapiens dm2 and M1 shapes differ significantly and
that this difference is primarily related to hypocone size
and projection. Allometry accounted for a small but significant
proportion of the total morphological variance. We
found the magnitude of the allometric effect to be significantly
stronger in Neandertals than in H. sapiens. Procrustes
distances were significantly different between the
two tooth classes in Neandertals, but not among H. sapiens
groups. Nevertheless, we could not reject the null hypothesis
that the two species share the same allometric trajectory.
Although size clearly contributes to the unique shape
of the Neandertal dm2 and M1, the largest H. sapiens teeth
do not exhibit the most Neandertal-like morphology.
Hence, additional factors must contribute to the differences
in dm2 and M1 crown shape between these two species. We
suggest an investigation of the role of timing and rate of
development on the shapes of the dm2 and M1 may provide
further answers
Technical Note: Virtual reconstruction of KNM-ER 1813 Homo habilis cranium
No full textA very limiting factor for paleoanthropological studies is the poor state of preservation of the human fossil record, where fragmentation and deformation are considered normal. Although anatomical information can still be gathered from a distorted fossil, such specimens must typically be excluded from advanced morphological and morphometric analyses, thus reducing the fossil sample size and, ultimately, our knowledge of human evolution. In this contribution we provide the first digital reconstruction of the KNM-ER 1813 Homo habilis cranium. Based on state of-the-art three-dimensional digital modeling and geometric morphometric (GM) methods, the facial portion was aligned to the neurocranium, the overall distortion was removed, and the missing regions were restored. The reconstructed KNM-ER 1813 allows for an adjustment of the anthropometric measurements gathered on the original fossil. It is suitable for further quantitative studies, such as GM analyses focused on skull morphology or for finite element analysis to explore the mechanics of early Homo feeding behavior and diet
Taxonomic differences in deciduous upper second molar crown outlines of Homo sapiens, Homo neanderthalensis and Homo erectus
No full textA significant number of Middle to Late Pleistocene sites contain primarily (and sometimes only) deciduous teeth (e.g., Grotta del Cavallo, Mezmaiskaya, Blombos). Not surprisingly, there has been a recent renewed interest in deciduous dental variation, especially in the context of distinguishing Homo neanderthalensis and Homo sapiens. Most studies of the deciduous dentition of fossil hominins have focused on standard metrical variation but morphological (non-metric and morphometric) variation also promises to shed light on long standing taxonomic questions. This study examines the taxonomic significance of the crown outline of the deciduous upper second molar through principal components analysis and linear discriminant analysis. We examine whether or not the crown shape of the upper deciduous second molar separates H. neanderthalensis from H. sapiens and explore whether it can be used to correctly assign individuals to taxa. It builds on previous studies by focusing on crown rather than cervical outline and by including a large sample of geographically diverse recent human populations. Our samples include 17 H. neanderthalensis, five early H. sapiens, and 12 Upper Paleolithic H. sapiens. In addition, we include two Homo erectus specimens in order to evaluate the polarity of crown shape differences observed between H. neanderthalensis and H. sapiens. Our results show that crown outline shape discriminates H. sapiens and H. neanderthalensis quite well, but does not do well at distinguishing H. erectus from H. sapiens. We conclude that the crown outline shape observed in H. sapiens is a primitive retention and that the skewed shape observed in H. neanderthalensis is a derived condition. Finally, we explore the phylogenetic implications of the results for the H. erectus molars
Taxonomic differences in deciduous lower first molar crown outlines of Homo sapiens and Homo neanderthalensis
No full textRésumé de thèse - Normes et variations de la production lithique durant le Châtelperronien: la séquence de la Grande-Roche-de-la-Plématrie à Quinçay (Vienne)
No full textInternational audienceThèse de doctorat soutenue le 28 juin 2011 à l'université de Paris Ouest Nanterre-La Défense sous la direction de Éric Boëda et de Jean-Jacques Hublin
Résumé de thèse - Normes et variations de la production lithique durant le Châtelperronien: la séquence de la Grande-Roche-de-la-Plématrie à Quinçay (Vienne)
No full textInternational audienceThèse de doctorat soutenue le 28 juin 2011 à l'université de Paris Ouest Nanterre-La Défense sous la direction de Éric Boëda et de Jean-Jacques Hublin
Exploring the biomechanics of taurodontism
No full textTaurodontism (i.e. enlarged pulp chamber with concomitant apical displacement of the root bi/trifurcation) is considered a dental anomaly with relatively low incidence in contemporary societies, but it represents a typical trait frequently found in Neandertal teeth. Four hypotheses can be envisioned to explain the high frequency in Neandertals: adaptation to a specific occlusal loading regime (biomechanical advantage), adaptation to a high attrition diet, pleiotropic or genetic drift effects. In this contribution we used finite element analysis (FEA) and advanced loading concepts based on macrowear information to evaluate whether taurodontism supplies some dental biomechanical advantages. Loads were applied to the digital model of the lower right first molar (RM1 ) of the Neandertal specimen Le Moustier 1, as well as to the digital models of both a shortened and a hyper-taurodontic version of Le Moustier RM1 . Moreover, we simulated a scenario where an object is held between teeth and pulled in different directions to investigate whether taurodontism might be useful for para-masticatory activities. Our results do not show any meaningful difference among all the simulations, pointing out that taurodontism does not improve the functional biomechanics of the tooth and does not favour para-masticatory pulling activities. Therefore, taurodontism should be considered either an adaptation to a high attrition diet or most likely the result of pleiotropic or genetic drift effects. Finally, our results have important implications for modern dentistry during endodontic treatments, as we observed that filling the pulp chamber with dentine-like material increases tooth stiffness, and ultimately tensile stresses in the crown, thus favouring tooth failure
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