Shared Pattern of Endocranial Shape Asymmetries among Great Apes, Anatomically Modern Humans, and Fossil Hominins

Anatomical asymmetries of the human brain are a topic of major interest because of their link with handedness and cognitive functions. Their emergence and occurrence have been extensively explored in human fossil records to document the evolution of brain capacities and behaviour. We quantified for the first time antero-posterior endocranial shape asymmetries in large samples of great apes, modern humans and fossil hominins through analysis of “virtual” 3D models of skull and endocranial cavity and we statistically test for departures from symmetry. Once based on continuous variables, we show that the analysis of these brain asymmetries gives original results that build upon previous analysis based on discrete traits. In particular, it emerges that the degree of petalial asymmetries differs between great apes and hominins without modification of their pattern. We indeed demonstrate the presence of shape asymmetries in great apes, with a pattern similar to modern humans but with a lower variation and a lower degree of fluctuating asymmetry. More importantly, variations in the position of the frontal and occipital poles on the right and left hemispheres would be expected to show some degree of antisymmetry when population distribution is considered, but the observed pattern of variation among the samples is related to fluctuating asymmetry for most of the components of the petalias. Moreover, the presence of a common pattern of significant directional asymmetry for two components of the petalias in hominids implicates that the observed traits were probably inherited from the last common ancestor of extant African great apes and Homo sapiens

The Grotta Guattari mandibular remains in the Italian human evolutionary context: A morphological and morphometrical overlook of the Neanderthal jaw

Within the Italian human fossil record, the mandibular remains Guattari 2 and Guattari 3 are representatives of Neanderthal populations living in the Italian peninsula from the beginning of the MIS 3. These were recovered from the Mount Circeo and date between ca. 57 and 51 B.P. The integrity and the contemporaneity of these two human remains make them suitable candidates for intraspecific variability investigation. In the present study, we provide a detailed morphological and morphometrical description of these specimens. This is supported by an analysis and comparison of the symphysis profile with a reference collection composed of modern human, Neanderthals and Middle Pleistocene hominins. In terms of morphology, both specimens show Neanderthal derived features such as a wide retromolar space and an anterior position of the mental foramen with, however, some inter-individual differences in terms of expression of features. Guattari 2 shows a general morphology which could be integrated in the range of Neanderthals from MIS3-4. On the other hand, Guattari 3 present a morphology closer to more ancient Neanderthals (MIS4-5). Mandibular remains constitute one of the most variable elements of the skeleton. The reason of such variability could be explained by several factors: sexual dimorphism, inter-individual variability or differences in chronology, which will be tested in this study. The reassessment of Guattari 2 and 3 has the potential to shed new light on the morphology of mandibular fossil specimens from the Italian peninsula, and increase our knowledge of the mandibular variability of the Neanderthals

In memoriam Dominique Henry-Gambier (1950-2022) : les comportements mortuaires paléolithiques du terrain à l’interprétation

Dominique Henry-Gambier nous a quittés le 17 septembre 2022 après un long et courageux combat contre la maladie, qui ne l’empêchait pas de rester attentive à l’actualité scientifique. Elle en discutait avec fougue comme à son habitude ; elle poursuivait aussi la mise au propre de ses notes et la réflexion de ses articles en cours. Et comme toujours, elle restait bienveillante à l’écoute des besoins des autres, disponible pour étudier les propositions de collaborations qu’elle n’acceptait néa..

Internal cranial features of the Mojokerto child fossil (East Java, Indonesia)

International audienceThe island of Java, Indonesia, has produced a remarkable number of fossil hominid remains. One of the earliestspecimens was found in Perning and consists of an almost complete calvaria belonging to a juvenile individual, knownas the Mojokerto child (Perning I). Using computed tomography, this study details its endocranial features. Thespecimen is still filled with sediment, but its inner surface is well preserved, and we were able to reconstruct itsendocranial features electronically. The Mojokerto endocast is the only cerebral evidence available for such a young Homo erectus individual. We provide an analytical description, make comparisons with endocasts of other fossil hominids and modern humans, and discuss its individual age and taxonomic affinities. The ontogenetic pattern indicated by the Mojokerto child suggests that the growth and development of the Homo erectus brain was different from that of modern humans. The earliest stages of development, as characterized by this individual, correspond to important supero-inferior expansion, and relative rounding of the cerebrum. The following stages differ from that of modern humans by marked antero-posterior flattening of the brain and particularly antero posterior development of the frontal lobes, resulting in the adult H. erectus morphology

Where are inion and endinion? Variations of the exo- and endocranial morphology of the occipital bone during hominin evolution

The occipital bone is frequently investigated in paleoanthropological studies because it has several features that help to differentiate various fossil hominin species. Among these features is the separation between inion and endinion, which has been proposed to be an autapomorphic trait in (Asian) Homo erectus. Methodologies are developed here to quantify for the first time the location of these anatomical points, and to interpret their variation due to the complex interactions between exocranial and endocranial size and shape of the occipital and nuchal planes, as well as the occipital lobes and cerebellum. On the basis of our analysis, neither 'the separation between inion and endinion' nor 'endinion below inion' can be considered as an autapomorphic trait in H. erectus, since this feature is a condition shared by extant African great apes and fossil hominins. Moreover, our results show that the exo- and endocranial anatomy of the occipital bone differs between hominins (except Paranthropus boisei specimens and KNM-ER 1805) and great apes. For example, chimpanzees and bonobos are characterized by a very high position of inion and their occipital bone shows an antero-posterior compression. However, these features are partly correlated with their small size when compared with hominins. Asian H. erectus specimens have a thick occipital torus, but do not differ from other robust specimens, neither in this feature nor in the analysed exo- and endocranial proportions of the occipital bone. Finally, the apparent brain size reduction during the Late Pleistocene and variation between the sexes in anatomically modern humans (AMH) reflect that specimens with smaller brains have a relatively larger posterior height of the cerebellum. However, this trend is not the sole explanation for the 'vertical shift' of endinion above inion that appears occasionally and exclusively in AMH. © 2011 Elsevier Ltd.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Les vestiges humains : un assemblage original

International audienc

The Fossil Human from Rabat-Kébibat (Morocco): Comparative Study of the Cranial and Mandibular Fragments

As part of the geological and chronological recontextualization of the Rabat-Kébibat quarry performed by a Franco-Moroccan team of geologists, the human remains discovered in the site and already published were reassessed. The human remains assemblage is composed of 23 cranial fragments, a mandible (including on the right I1, P3, P4, the roots of M1, M2, and M3, and of the left I1, I2, C, P3, P4, and M1), and the left half of the maxillary (including I1, I2, P3, P4, M1, and M2). Through a micro-computerized tomography analysis, the internal structure of the parietal fragment (evaluation of the thickness of the compact table and diploe) and the mandible was examined. Geometric morphometrics were applied on the tridimensional model of the mandible to investigate the conformation of the symphyseal outlines. Results were compared to a large reference collection composed of African, Asiatic, and European hominin fossils, from different chronological range. Our results allow us to clarify the phylogenetic position of the human remains from Rabat-Kebibat, in particular their relationship with other North African hominins