Virtual ancestor reconstruction: Revealing the ancestor of modern humans and Neandertals.

The timing and geographic origin of the common ancestor of modern humans and Neandertals remain controversial. A poor Pleistocene hominin fossil record and the evolutionary complexities introduced by dispersals and regionalisation of lineages have fuelled taxonomic uncertainty, while new ancient genomic data have raised completely new questions. Here, we use maximum likelihood and 3D geometric morphometric methods to predict possible morphologies of the last common ancestor of modern humans and Neandertals from a simplified, fully resolved phylogeny. We describe the fully rendered 3D shapes of the predicted ancestors of humans and Neandertals, and assess their similarity to individual fossils or populations of fossils of Pleistocene age. Our results support models of an Afro-European ancestral population in the Middle Pleistocene (Homo heidelbergensis sensu lato) and further predict an African origin for this ancestral population.This study was partially funded by the Fyssen Foundation, and an Advanced ERC Award (IN-AFRICA Project). For permission to study specimens in their care we thank directors and curators of the following institutions: Musée de l’Homme (Paris, France); Institut de Paléontologie Humaine (Paris, France); Staatliches Museum für Naturkunde (Stuttgart, Germany); Aristotle University of Thessaloniki (Thessaloniki, Greece); Soprintendenza Archeologia del Lazio, Servizio di Antropologia (Rome, Italy); Museo di Antropologia G. Sergi (Sapienza Università di Roma, Italy); Museo preistorico-etonografico ‘L. Pigorini’ (Rome, Italy); National Museums of Kenya (Nairobi, Kenya); National Museum (Bloemfontein, Republic of South Africa); Natural History Museum (London, UK); Duckworth Collection (Cambridge, UK). We thank F. Lahr and F. Rivera for assistance with CT-scanning and E. Delson, R. Foley, L. Puymerail and A. Froment for help and ideas. Finally, we thank M. Plavcan, D. Polly, the Associate Editor and two anonymous reviewers for valuable comments and criticisms of earlier drafts which contributed to the improvement of this study.This is the author accepted manuscript. The final version is available from Elsevier via http://dx.doi.org/10.1016/j.jhevol.2015.11.00

Deciphering African late middle Pleistocene hominin diversity and the origin of our species

Abstract: The origin of Homo sapiens remains a matter of debate. The extent and geographic patterning of morphological diversity among Late Middle Pleistocene (LMP) African hominins is largely unknown, thus precluding the definition of boundaries of variability in early H. sapiens and the interpretation of individual fossils. Here we use a phylogenetic modelling method to predict possible morphologies of a last common ancestor of all modern humans, which we compare to LMP African fossils (KNM-ES 11693, Florisbad, Irhoud 1, Omo II, and LH18). Our results support a complex process for the evolution of H. sapiens, with the recognition of different, geographically localised, populations and lineages in Africa – not all of which contributed to our species’ origin. Based on the available fossils, H. sapiens appears to have originated from the coalescence of South and, possibly, East-African source populations, while North-African fossils may represent a population which introgressed into Neandertals during the LMP

Who were the Nataruk people? Mandibular morphology among late Pleistocene and early Holocene fisher-forager populations of West Turkana (Kenya).

Africa is the birthplace of the species Homo sapiens, and Africans today are genetically more diverse than other populations of the world. However, the processes that underpinned the evolution of African populations remain largely obscure. Only a handful of late Pleistocene African fossils (∼50-12 Ka) are known, while the more numerous sites with human fossils of early Holocene age are patchily distributed. In particular, late Pleistocene and early Holocene human diversity in Eastern Africa remains little studied, precluding any analysis of the potential factors that shaped human diversity in the region, and more broadly throughout the continent. These periods include the Last Glacial Maximum (LGM), a moment of extreme aridity in Africa that caused the fragmentation of population ranges and localised extinctions, as well as the 'African Humid Period', a moment of abrupt climate change and enhanced connectivity throughout Africa. East Africa, with its range of environments, may have acted as a refugium during the LGM, and may have played a critical biogeographic role during the heterogene`ous environmental recovery that followed. This environmental context raises a number of questions about the relationships among early Holocene African populations, and about the role played by East Africa in shaping late hunter-gatherer biological diversity. Here, we describe eight mandibles from Nataruk, an early Holocene site (∼10 Ka) in West Turkana, offering the opportunity of exploring population diversity in Africa at the height of the 'African Humid Period'. We use 3D geometric morphometric techniques to analyze the phenotypic variation of a large mandibular sample. Our results show that (i) the Nataruk mandibles are most similar to other African hunter-fisher-gatherer populations, especially to the fossils from Lothagam, another West Turkana locality, and to other early Holocene fossils from the Central Rift Valley (Kenya); and (ii) a phylogenetic connection may have existed between these Eastern African populations and some Nile Valley and Maghrebian groups, who lived at a time when a Green Sahara may have allowed substantial contact, and potential gene flow, across a vast expanse of Northern and Eastern Africa

Gravettian cranial morphology and human group affinities during the European Upper Palaeolithic.

Archaeologically defined Upper Palaeolithic (UP, 45,000-10,000 years ago) "cultures" are often used as proxies to designate fossil populations. While recent genomic studies have partly clarified the complex relationship between European UP "cultures" and past population dynamics, they leave open numerous questions regarding the biological characterization of these human groups, especially regarding the Mid-UP period (MUP, 33,000-24,000 years ago), which encompasses a pan-European cultural mosaic (Gravettian) with several regional facies. Here, we analyse a large database of well-dated and well-preserved UP crania, including MUP specimens from South-West France (SWF) and Moravia, using 3D geometric morphometrics to test for human group affinities. Our results show that the Gravettian makers from these two regions form a remarkably phenetically homogeneous sample which is different from, and more homogeneous than, the Late UP sample. Those results are congruent with genomic studies indicating a genetic continuity within the Gravettian manufacturers and a discontinuity marked by the Last Glacial Maximum (LGM). Moreover, our study expands the geographical range of the MUP phenetic continuity to SWF, for which aDNA data are scarce, and clarifies the post-LGM European population structure in SWF, with a possible dual ancestry stemming from different LGM refugia

A new Upper Pleistocene hominin calvarium from West-Turkana (Kenya)

The Upper Pleistocene (UP) African hominin fossil record is extremely scarce. Only two well-preserved specimens dated to 50,000-30,000 years ago are available: the Hofmeyr cranium from South Africa, and the Nazelt Khater 2 (NK2) skeleton from Egypt. Here, we present a new hominin calvarium (NG1) found in 2015 at Ngingolea Idome (West Turkana, Kenya) and directly dated to 30,000-33,000 years ago by U-series. The NG1 calvarium was reconstructed from multiple small fragments which were found on ..

The Stem Species of Our Species: A Place for the Archaic Human Cranium from Ceprano, Italy

One of the present challenges in the study of human evolution is to recognize the hominin taxon that was ancestral to Homo sapiens. Some researchers regard H. heidelbergensis as the stem species involved in the evolutionary divergence leading to the emergence of H. sapiens in Africa, and to the evolution of the Neandertals in Europe. Nevertheless, the diagnosis and hypodigm of H. heidelbergensis still remain to be clarified. Here we evaluate the morphology of the incomplete cranium (calvarium) known as Ceprano whose age has been recently revised to the mid of the Middle Pleistocene, so as to test whether this specimen may be included in H. heidelbergensis. The analyses were performed according to a phenetic routine including geometric morphometrics and the evaluation of diagnostic discrete traits. The results strongly support the uniqueness of H. heidelbergensis on a wide geographical horizon, including both Eurasia and Africa. In this framework, the Ceprano calvarium – with its peculiar combination of archaic and derived traits – may represent, better than other penecontemporaneous specimens, an appropriate ancestral stock of this species, preceding the appearance of regional autapomorphic features

What do brain endocasts tell us? A comparative analysis of the accuracy of sulcal identification by experts and perspectives in palaeoanthropology

Palaeoneurology is a complex field as the object of study, the brain, does not fossilize. Studies rely therefore on the (brain) endocranial cast (often named endocast), the only available and reliable proxy for brain shape, size and details of surface. However, researchers debate whether or not specific marks found on endocasts correspond reliably to particular sulci and/or gyri of the brain that were imprinted in the braincase. The aim of this study is to measure the accuracy of sulcal identification through an experiment that reproduces the conditions that palaeoneurologists face when working with hominin endocasts. We asked 14 experts to manually identify well-known foldings in a proxy endocast that was obtained from an MRI of an actual in vivo Homo sapiens head. We observe clear differences in the results when comparing the non-corrected labels (the original labels proposed by each expert) with the corrected labels. This result illustrates that trying to reconstruct a sulcus following the very general known shape/position in the literature or from a mean specimen may induce a bias when looking at an endocast and trying to follow the marks observed there. We also observe that the identification of sulci appears to be better in the lower part of the endocast compared to the upper part. The results concerning specific anatomical traits have implications for highly debated topics in palaeoanthropology. Endocranial description of fossil specimens should in the future consider the variation in position and shape of sulci in addition to using models of mean brain shape. Moreover, it is clear from this study that researchers can perceive sulcal imprints with reasonably high accuracy, but their correct identification and labelling remains a challenge, particularly when dealing with extinct species for which we lack direct knowledge of the brain

Age of the oldest known Homo sapiens from eastern Africa.

Efforts to date the oldest modern human fossils in eastern Africa, from Omo-Kibish1-3 and Herto4,5 in Ethiopia, have drawn on a variety of chronometric evidence, including 40Ar/39Ar ages of stratigraphically associated tuffs. The ages that are generally reported for these fossils are around 197 thousand years (kyr) for the Kibish Omo I3,6,7, and around 160-155 kyr for the Herto hominins5,8. However, the stratigraphic relationships and tephra correlations that underpin these estimates have been challenged6,8. Here we report geochemical analyses that link the Kamoya's Hominid Site (KHS) Tuff9, which conclusively overlies the member of the Omo-Kibish Formation that contains Omo I, with a major explosive eruption of Shala volcano in the Main Ethiopian Rift. By dating the proximal deposits of this eruption, we obtain a new minimum age for the Omo fossils of 233 ± 22 kyr. Contrary to previous arguments6,8, we also show that the KHS Tuff does not correlate with another widespread tephra layer, the Waidedo Vitric Tuff, and therefore cannot anchor a minimum age for the Herto fossils. Shifting the age of the oldest known Homo sapiens fossils in eastern Africa to before around 200 thousand years ago is consistent with independent evidence for greater antiquity of the modern human lineage10.Leverhulme Trust Cambridge-Africa ALBORADA Research Fund SFI award 13/RC/209

Les vestiges humains gravettiens dans le Sud-Ouest de la France : bilan du projet Gravett’os

Cette communication présente les principaux résultats du projet Gravett’Os, qui porte sur du matériel anthropologique du Sud-Ouest de la France (découvertes récentes et reprises des collections anciennes) associé au Gravettien (34-24 000 cal BP). Ce projet a permis l’identification de 32 individus provenant de 5 sites (Cussac, Fournol, Gargas, Abri Pataud, Cro-Magnon). Nos études confortent les analyses précédentes sur les comportements au Gravettien : extrême mobilité et division sexuelle du..

Frontal sinuses and human evolution

The frontal sinuses are cavities inside the frontal bone located at the junction between the face and the cranial vault and close to the brain. Despite a long history of study, understanding of their origin and variation through evolution is limited. This work compares most hominin species’ holotypes and other key individuals with extant hominids. It provides a unique and valuable perspective of the variation in sinuses position, shape, and dimensions based on a simple and reproducible methodology. We also observed a covariation between the size and shape of the sinuses and the underlying frontal lobes in hominin species from at least the appearance of Homo erectus. Our results additionally undermine hypotheses stating that hominin frontal sinuses were directly affected by biomechanical constraints resulting from either chewing or adaptation to climate. Last, we demonstrate their substantial potential for discussions of the evolutionary relationships between hominin species