Welcome

 I am employed by the French scientific research centre (CNRS) and I work in a famous institution, the Museum national d’Histoire naturelle, in the Musée de l'HommeMy main areas of research concern the morphological evolution of hominins, with a particular interest on internal cranial morphology observed by mean of imaging methodologies.

 

I am also responsible of the X-ray imaging platform of the MNHN (AST-RX) and redactor in chief of the Bulletins et Mémoires de la Société d'Anthropologie de Paris (feel free to submit your work to the BMSAP!). I have published 50 papers in peer-reviewed journals and gave over 85 communications in scientific meetings. I have been contributing to the diffusion of science to a wide audience (videos, press).

 

 Below, some examples of my previous works are briefly described


Balzeau A., Charlier P. What do cranial bones of LB1 tell us about Homo floresiensis? Journal of Human Evolution 93, 12-24.

 

Cranial vault thickness (CVT) of Liang Bua 1, the specimen that is proposed to be the holotype of H. floresiensis, has not yet been described in detail and compared with samples of fossil hominins, anatomically modern humans or microcephalic skulls. In addition, a complete description from a forensic and pathological point of view has not yet been carried out. It is important to evaluate scientifically if features related to CVT bring new information concerning the possible pathological status of LB1, and if it helps to recognize affinities with any hominin species and particularly if the specimen could belong to the species H. sapiensMedical examination of the skull based on a micro-CT examination clearly brings to light the presence of a sincipital T (a non-metrical variant of normal anatomy), a scar from an old frontal trauma without any evident functional consequence, and a severe bilateral hyperostosis frontalis interna that may have modified the anterior morphology of the endocranium of LB1. We also show that LB1 displays characteristics, related to the distribution of bone thickness and arrangements of cranial structures, that are plesiomorphic traits for hominins, at least for H. erectus s.l. relative to later hominins. All the microcephalic skulls analyzed here share the derived condition of H. sapiens. Cranial vault thickness does not help to clarify the definition of the species H. floresiensis but we conclude that there is no support for the attribution of LB1 to H. sapiens as there is no evidence of systemic pathology and because it does not have any of the apomorphic traits of our species.


Mounier A., Balzeau A., Caparros M., Grimaud-Hervé D. : Brain, calvarium, cladistics: a new approach to an old question, who are modern humans and Neandertals? Journal of Human Evolution 92, 22-36.

 

The evolutionary history of the genus Homo is the focus of major research efforts in palaeoanthropology. However, the use of palaeoneurology to infer phylogenies of our genus is rare. Here we use cladistics to test the importance of the brain in differentiating and defining Neandertals and modern humans. We demonstrate that the joint use of endocranial and calvarial features with cladistics provides a unique means to understand the evolution of the genus Homo. The main results of this study indicate that: (i) the endocranial features are more phylogenetically informative than the characters from the calvarium; (ii) the specific differentiation of Neandertals and modern humans is mostly supported by well-known calvarial autapomorphies; (iii) the endocranial anatomy of modern humans and Neandertals show strong similarities, which appeared in the fossil record with the last common ancestor of both species; and (iv) apart from encephalisation, human endocranial anatomy changed tremendously during the end of the Middle Pleistocene. This may be linked to major cultural and technological novelties that had happened by the end of the Middle Pleistocene (e.g., expansion of the Middle Stone Age (MSA) in Africa and Mousterian in Europe). The combined study of endocranial and exocranial anatomy offers opportunities to further understand human evolution and the implication for the phylogeny of our genus.


La Ferrassie 8 Neandertal child reloaded: New remains and re-assessment of the original collectionJournal of Human Evolution (2015) 82, 107-126.

 

The study of brain structural asymmetries as anatomical substrates of functional asymmetries in extant humans, great apes, and fossil hominins is of major importance in understanding the structural basis of modern human cognition. We demonstrate both an absolute and relative bilateral increase in the size of the third frontal convolution in width and length between Pan species, as well as in hominins. We also observed a global bilateral increase in the size of the third frontal convolution across all species during hominin evolution, but also non-allometric intra-group variations independent of brain size within the fossil samples. Finally, our results show that the commonly accepted leftward asymmetry of Broca's cap is biased by qualitative observation of individual specimens. The trend during hominin evolution seems to be a reduction in size on the left compared with the right side, and also a clearer definition of the area. Our results also suggest that the pattern of brain asymmetries is similar between Pan paniscus and hominins, leaving the gradient of the degree of asymmetry as the only relevant structural parameter. As the anatomical substrate related to brain asymmetry has been present since the appearance of the hominin lineage, it is not possible to prove a direct relationship between the extent of variations in the size, shape, and asymmetries of the third frontal convolution and the origin of language.


Variations in size, shape and asymmetries of the third frontal convolution in hominids: paleoneurological implications for hominin evolution and the origin of languageJournal of Human Evolution (2014) 76, 116-128.

 

The study of brain structural asymmetries as anatomical substrates of functional asymmetries in extant humans, great apes, and fossil hominins is of major importance in understanding the structural basis of modern human cognition. We demonstrate both an absolute and relative bilateral increase in the size of the third frontal convolution in width and length between Pan species, as well as in hominins. We also observed a global bilateral increase in the size of the third frontal convolution across all species during hominin evolution, but also non-allometric intra-group variations independent of brain size within the fossil samples. Finally, our results show that the commonly accepted leftward asymmetry of Broca's cap is biased by qualitative observation of individual specimens. The trend during hominin evolution seems to be a reduction in size on the left compared with the right side, and also a clearer definition of the area. Our results also suggest that the pattern of brain asymmetries is similar between Pan paniscus and hominins, leaving the gradient of the degree of asymmetry as the only relevant structural parameter. As the anatomical substrate related to brain asymmetry has been present since the appearance of the hominin lineage, it is not possible to prove a direct relationship between the extent of variations in the size, shape, and asymmetries of the third frontal convolution and the origin of language.


Paper by Rendu, Beauval, Crevecoeur, Bayle, Balzeau, Bismuth, Bourguignon, Delfour, Faivre, Lacrampe-Cuyaubère, Tavormina, Todisco, Turq, Maureille: Evidence supporting an intentional Neandertal burial at La Chapelle-aux-Saints. PNAS 111, 81-86.

 

For decades, scholars have questioned the existence of burial in Europe prior to the arrival of Modern Humans. An approach combining a global field recovery and the reexamination of the previously discovered Neandertal remains has been undertaken in the site of La Chapelle-aux-Saints, France, where the hypothesis of a Neandertal burial was raised for the first time. This project has concluded that the Neandertal of La Chapelle-aux-Saints was deposit in a pit dug by other members of its group and protected by a rapid covering from any disturbance. These discoveries attest the existence of West European Neandertal burial and of the Neandertal cognitive capacity to produce it.


New information on the modifications of the neandertal suprainiac fossa during growth and development and on its etiologyAmerican journal of physical anthropology (2013) 151, 38-48.

 

Read the comment in the CNRS international magazine. Follow the link or click on the image. 


Thickened cranial vault and parasagittal keeling, correlated traits and autapomorphies of Homo erectus? Journal of Human Evolution (2013) 64, 631-344.

 

H. erectus sensu lato is a key species in the hominin fossil record for the study of human evolution, being one of the first species discovered and perhaps the most documented, but also because of its long temporal range and having dispersed out of Africa earlier than any other human species. Here I test two proposed autapomorphic traits of H. erectus, namely the increased thickness of the upper cranial vault and parasagittal keeling. The definition of these features and their expression and variation among hominids are discussed. The results indicate that the upper vault in Asian H. erectus is not absolutely thicker compared with fossil anatomically modern Homo sapiens, whereas Broken Hill and Petralona have values above the range of variation of H. erectus. Moreover, this anatomical region in Asian H. erectus is not significantly thicker compared with Pan paniscus. In addition, these results demonstrate that cranial vault thickness should not be used to make hypotheses regarding sexual attribution of fossil hominin specimens. I also show that the relation between relief on the external surface of the upper vault, parasagittal keeling and bregmatic eminence, and bone thickness is complex. In this context, the autapomorphic status of the two analysed traits in H. erectus may be rejected.

Nevertheless, different patterns in the distribution of bone thickness on the upper vault were identified. The pattern of bone thickness distribution observed in Asian H. erectusP. paniscus, possibly australopiths, and early Homo or Homo ergaster/erectus appears to be shared by these different species and would be a plesiomorphic trait among hominids. In contrast, two apomorphic states for this feature were identified for Neandertals and H. sapiens.


First description of the Cro-Magnon 1 endocast and study of brain variation and evolution in anatomically modern Homo sapiens. Bulletins et Mémoires de la Société d'Anthropologie de Paris (2013) 25, 1-18.

 

Variations in the size and shape of the endocranium are a useful means of distinguishing between different hominin species, while brain asymmetry is related to behaviour and cognitive capacities. However, we have only little information about variations in endocranial form, size and shape in fossil anatomically modern Homo sapiens and about the evolution of the brain since the emergence of our species. One good illustration of this limited knowledge is that one of the first fossil H. sapiens discovered, in 1868, that is also one of the oldest well-preserved European specimen has never been studied in what concerns its endocranial morphology. The first aim of this study was to propose a detailed description of the endocranial anatomy of Cro-Magnon 1, using imaging methodologies, including an original methodology to quantify endocranial asymmetries. The second aim was to compare samples of the fossil and extant AMH in order to document differences in the form, size and shape of the endocasts. A decrease in absolute endocranial size since the Upper Palaeolithic was noticeable. Although both extant and older endocrania have the same anatomical layout, we found non-allometric differences in the relative size and organization of different parts of the brain. These document previously unknown intraspecific variations in the H. sapiens brain, demonstrating its plasticity, with some areas (frontal, occipital lobes) having been more subject to variation than others (parieto-temporal, cerebellar lobes). That may be due to constraints to maintain an optimal performance while reducing in size and changing in shape during our recent evolution.  

Schematic representation in the right lateral view of the variations in endocranial anatomy between a fossil (external outline corresponding to Cro-Magnon 1) and a “mean” extant anatomically modern human (internal outline)
Schematic representation in the right lateral view of the variations in endocranial anatomy between a fossil (external outline corresponding to Cro-Magnon 1) and a “mean” extant anatomically modern human (internal outline)

Variations and asymmetries in regional brain surface in the genus Homo. Journal of Human Evolution (2012) 62, 696-706.

 

 We analyse variations of the surface of the frontal, parieto-temporal and occipital lobes among different species of Homo. We also test for the possible asymmetries of these features in a large sample of modern humans. Our results show that the general pattern of asymmetry for the regional brain surfaces in fossil species of Homo does not seem to be different from the pattern described in a large sample of anatomically modern H. sapiens. It also appears that Asian H. erectus specimens are discriminated from all other samples of Homo, including African and Georgian specimens that are also sometimes included in that taxon. The Asian fossils show a significantly smaller relative size of the parietal and temporal lobes. Neandertals and anatomically modern H. sapiens, who share the largest endocranial volume of all hominins, show differences when considering the relative contribution of the frontal, parieto-temporal and occipital lobes. These results illustrate an original variation in the pattern of brain organization in hominins independent of variations in total size. The globularization of the brain and the enlargement of the parietal lobes could be considered derived features observed uniquely in anatomically modern H. sapiens

Variation in regional brain surfaces during hominin evolution
Variation in regional brain surfaces during hominin evolution

brain asymetries and human evolution
Illustration of the protocol used to quantify the endocranial petalias and frequency distribution of petalia components in hominids.

Shared pattern of quantified endocranial shape asymmetries among anatomically modern humans, great apes and fossil hominins. PLoS ONE 7(1): e29581.

 

The degree of petalial asymmetries differs between great apes and hominins without modification of their pattern. We 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, the pattern of variation in the position of the frontal and occipital poles on the right and left hemispheres 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 2 components of the petalias in hominids implicates that the observed traits were inherited from the last common ancestor of extant African great apes and H.sapiens.

These results have implications for the relationships between endocranial shape asymmetries and functional capacities in hominins. It emphasizes the uncoupling between lateralized activities, some of them well probably distinctive to Homo, and large-scale cerebral lateralization itself, which is not unique to Homo.


Vertical dissociation of inion from endinion

Where are inion and endinion ? Variations of the exo- and endocranial morphology of the occipital bone during hominin evolution. Journal of Human Evolution (2011) 61, 488-502. 

 

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 great apes and fossil hominins.

Moreover, the anatomy of the occipital bone differs between most hominins and great apes. Asian H. erectus 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 bone. Finally, brain size reduction during the Late Pleistocene and variation between the sexes in H. sapiens 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.


Suprainiac fossa in Neandertals

Is the suprainiac fossa a Neandertal autapomorphy? A complementary external and internal investigation. Journal of Human Evolution (2010) 58, 1-22.

 

A similar pattern for the structural composition of the bone is found among all analyzed Neandertals (i.e., the suprainiac fossa corresponds to a thinning of the diploic layer with no substantial remodeling nor variation in the external table thickness in this area). We demonstrate that the depressions described in anatomically modern humans, as well as other hominin species, are not homologous to the suprainiac fossa of Neandertals. Consequently, we confirm the autapomorphic status of the Neandertal suprainiac fossa.


Applications of imaging methodologies to paleoanthropology: beneficial results relating to the preservation, management and development of collections. Comptes Rendus Palevol (2010) 9, 265-275.

 

The limited number of unearthed fossils and their accessibility are factors that hinder paleoanthropological studies. Original remains, but also osteological collections of extant specimens, have to be curated in optimal and adapted environments, and direct manipulation needs to be limited in order to preserve this irreplaceable patrimony. Imaging methodologies have recently provided ways for innovative advances in the preservation of these collections, as well as offering new perspectives to museographic displays and original scientific studies. Here, we describe recent examples of developments obtained from imaging methodologies and discuss methodological and ethical implications of these new “virtual” collections. Undeniably, “virtual anthropology” is an additional tool in our large set of analytical possibilities and for curators, with its specific constraints related to the particular nature of the analysed material. Finally, we suggest some possible guidelines for the optimisation of the preservation, management and development of collections while preserving their scientific exploitation.


the type specimen of the bonobo

Internal cranial anatomy of the type specimen of Pan paniscus and available data for study. Journal of Human Evolution (2009) 56, 205-208.

 

We completed classical observation of the type specimen 9338 of Pan paniscus and morphological and quantitative analyses of the internal structures using imaging methodologies. We describe and quantify its internal cranial features (i.e., paranasal and temporal bone pneumatisation) and its virtual endocast. We also provide a complete landmark description, as well as a 3D model in order to allow other scientists to include this key specimen in their own research (link).