Diversité taxonomique des Hominidés fossiles en Asie : de nouvelles méthodes pour une vieille question

Les objectifs de cette étude sont de déterminer si les fossiles d’Hominidés retrouvés en Asie du Sud-est représentent un ou plusieurs taxons, d’identifier ceux-ci, de mesurer les distances entre ces taxons et de les comparer à celles existant entre des espèces et sous-espèces actuelles phylogénétiquement proches (grands singes). Pour cela, nous avons utilisé les nouvelles méthodes de morphométrie géométrique. Vingt points repères tridimensionnels ont été numérisés sur un échantillon de 110 crânes : 18 spécimens fossiles issus d’Asie et datés de 6 000 à 1 150 000 ans, 31 spécimens d’Homo sapiens actuels, 31 spécimens de chimpanzés et 30 spécimens de gorilles. La méthode Procruste a été appliquée afn de séparer la variable taille des variables de conformation. Nous avons utilisé une nouvelle méthode originale en trois étapes, dans une démarche logique et objective. 1) La variabilité globale des quatre groupes a été explorée avec différents indices (variance, distances euclidiennes et de Manhattan). 2) Afin de s’affranchir des regroupement arbitraires de fossiles dans des catégories taxonomiques pré-établies, des analyses en composantes principales (ACP) et de classification (Neighbor Joining et UPGMA) ont permis d’identifier des sous-groupes au sein des quatre groupes (fossiles, H. sapiens, chimpanzés et gorilles). 3) Enfin, les distances de Mahalanobis entre ces différents sous-groupes ont été mesurées et comparées entre elles. Les résultats montrent que la variabilité globale des fossiles est significativement supérieure à celle des H. sapiens. Elle est également supérieure, mais de manière non significative, à celle des chimpanzés d’une part et des gorilles d’autre part. Les méthodes de classification et d’ACP ont permis d’identifier deux groupes au sein de l’échantillon des fossiles : un groupe d’affinité H. erectus et un autre d’affinité H. sapiens. La plus grande distance de Mahalanobis est observée entre les gorilles et les H. sapiens, puis entre les chimpanzés et les H. sapiens. Suit la distance entre les chimpanzés et les gorilles, qui est très proche de celle entre les H. sapiens actuels et les H. erectus. Cette dernière est proche de la distance entre les H. sapiens fossiles et les H. erectus. En revanche, la distance entre les H. sapiens fossiles et actuels est nettement inférieure et est comparable aux distances observées entre les différents sous-groupes identifiés au sein des H. sapiens actuels, des chimpanzés et des gorilles. Cette nouvelle méthode originale a permis de conclure que les fossiles étudiés appartiennent bien à deux taxons différents. Le premier (les H. sapiens fossiles) peut être considéré comme appartenant au même taxon que celui des hommes actuels. Le deuxième appartient à un taxon différent.The  objectives  of  this  study  were  to  determine  whether  the  fossils  discovered  in Asia  belong  to  one  or  several taxa, to identify them and to compare the distances between them to the distances between actual groups and species of anthropoids. For  this purpose, we have used new geometric morphometric methods. Twenty  three dimensional  landmarks were digitized on 110  skulls: 18  fossils  from Asia dated between 1,150,000  years and 6,000 BC, 31 modern Homo sapiens, 31 chimpanzees and 30 gorillas. Landmarks were registered by Generalized Procruste Analysis. We used a  logical and objective method with  three steps. 1) The  taxa variabilities were explored by using several distance  indices  (variance, Euclidean and Manhattan distances). 2) We have  chosen not  to arbitrarily group  fossils  in established taxonomic categories: Principal component analysis (PCA) and hierarchical classification methods (UPGMA and NJ) were applied  to  identify subgroups  for each of  the  four  taxa. Finally, Mahalanobis distances between  identified groups and subgroups were calculated and compared between each other. The  overall  variability  was  larger  for  the  fossil  group  than  for  any  of  the  three  actual  species,  although  the difference was statistically significant only for the comparison to the modern H. sapiens. Classification and PCA analysis identified two subgroups within the fossil group: one with an H. sapiens affinity and the other with an H. erectus affinity. The Mahalanobis distances were ordered as  follows  (decreasing order): gorilla/modern H. sapiens, chimpanzee/modern H. sapiens, chimpanzee/gorilla which was very similar to the distance between modern H. sapiens and H. erectus. This last distance was similar to the one between fossil H. sapiens and H. erectus. Distances between modern and fossil H. sapiens and between subgroups of actual species were similar and less than the preceding ones. We finally concluded that the fossils belong to two different taxa. The first (fossil H. sapiens) belongs to the same taxon as modern H. sapiens and the second, H. erectus, is different

Small Size in the Philippine Human Fossil Record: Is It Meaningful for a Better Understanding of the Evolutionary History of the Negritos?

Pygmy populations are recognized in several places over the world, especially in Western Africa and in Southeast Asia (Philippine negritos, for instance). Broadly defined as small-bodied Homo sapiens (compared with neighboring populations), their origins and the nature of the processes involved in the maintenance of their phenotype over time are highly debated. Major results have been recently obtained from population genetics on present-day negrito populations, but their evolutionary history remains largely unresolved. We present and discuss the Upper Pleistocene human remains recovered from Tabon Cave and Callao Cave in the Philippines, which are potentially highly relevant to these research questions. Human fossils have been recovered in large numbers from Tabon Cave (Palawan Island) but mainly from reworked and mixed sediments from several archaeological layers. We review and synthesize the long and meticulous collaborative work done on the archives left from the 1960s excavations and on the field. The results demonstrate the long history of human occupations in the cave, since at least ~30,000 BP. The examination of the Tabon human remains shows a large variability: large and robust for one part of the sample, and small and gracile for the other part. The latter would fit quite comfortably within the range of variation of Philippine negritos. Farther north, on Luzon Island, the human third metatarsal recently recovered from Callao Cave and dated to ~66,000 BP is now the oldest direct evidence of human presence in the Philippines. Previous data show that, compared with H. sapiens (including Philippine negritos), this bone presents a very small size and several unusual morphological characteristics. We present a new analytical approach using three-dimensional geometric morphometrics for comparing the Callao fossil to a wide array of extant Asian mammals, including nonhuman primates and H. sapiens. The results demonstrate that the shape of the Callao metatarsal is definitely closer to humans than to any other groups. The fossil clearly belongs to the genus Homo; however, it remains at the margin of the variation range of H. sapiens. Because of its great antiquity and the presence of another diminutive species of the genus Homo in the Wallace area during this time period (H. floresiensis), we discuss here in detail the affinities and potential relatedness of the Callao fossil with negritos that are found today on Luzon Island

Données quantitatives en anthropologie biologique : regards croisés

International audienc

Intégration polynésienne au Vanuatu (Mélanésie) : étude de cas sur les rapports entre société préexistante et individus migrants

Certaines sociétés humaines modernes de l’archipel du Vanuatu (Mélanésie) présentent des traits culturels polynésiens et parlent des langues polynésiennes. Ces caractéristiques diffèrent de celles des autres sociétés présentes dans l’archipel qui sont apparentés aux influences mélanésiennes régionales. On suppose que des migrations polynésiennes auraient particulièrement contribué à la formation de ces sociétés « polynésiennes » du Vanuatu lors du dernier millénaire. Pourtant, les études arch..

Homo luzonensis : principales caractéristiques et implications pour l’histoire évolutionnaire du genre

La nouvelle espèce Homo luzonensis a été décrite en 2019 à partir d’un assemblage constitué de treize éléments fossiles découverts dans la grotte de Callao (île de Luzon, Philippines) en 2007, 2011 et 2015. La datation directe de deux de ces fossiles par les séries de l’uranium indique des âges minimums respectifs de 50 000 et 67 000 ans. Dans cette présentation, nous montrons que ces spécimens présentent une combinaison de caractéristiques morphologiques primitives (i.e. ressemblant à Austra..

Craniodental Affinities of Southeast Asia\u27s Negritos and the Concordance with Their Genetic Affinities

Genetic research into Southeast Asia\u27s negritos has revealed their deep-rooted ancestry, with time depth comparable to that of Southwest Pacific populations. This finding is often interpreted as evidence that negritos, in contrast to other Southeast Asians, can trace much of their ancestry directly back to the early dispersal of Homo sapiens in the order of 70 kya from Africa to Pleistocene New Guinea and Australia. One view on negritos is to lump them and Southwest Pacific peoples into an Australoid race whose geographic distribution had included Southeast Asia prior to the Neolithic incursion of Mongoloid farmers. Studies into Semang osteology have revealed some hints of Southwest Pacific affinities in cranial shape, dental morphology, and dental metrical shape. On the other hand, the Andamanese have been shown to resemble Africans in their craniometrics and South Asians in their dental morphology, while Philippine negritos resemble Mongoloid Southeast Asians in these respects and also in their dental metrics. This study expands the scope of negrito cranial comparisons by including Melayu Malays and additional coverage of South Asians. It highlights the distinction between the Mongoloid-like Philippine negritos and the Andamanese and Semang (and Senoi of Malaya) with their non-Mongoloid associations. It proposes that the early/mid-Holocene dispersal of the B4a1a mitochondrial DNA clade across Borneo, the Philippines, and Taiwan may be important for understanding the distinction between Philippine and other negritos

The origins and persistence of Homo floresiensis on Flores: biogeographical and ecological perspectives

The finding of archaeological evidence predating 1 Ma and a small hominin species (Homo floresiensis) on Flores, Indonesia, has stimulated much research on its origins and ancestry. Here we take a different approach and examine two key questions – 1) how did the ancestors of H. floresiensis reach Flores and 2) what are the prospects and difficulties of estimating the likelihood of hominin persistence for over 1 million years on a small island? With regard to the first question, on the basis of the biogeography we conclude that the mammalian, avian, and reptilian fauna on Flores arrived from a number of sources including Java, Sulawesi and Sahul. Many of the terrestrial taxa were able to float or swim (e.g. stegodons, giant tortoises and the Komodo dragon), while the rodents and hominins probably accidentally rafted from Sulawesi, following the prevailing currents. The precise route by which hominins arrived on Flores cannot at present be determined, although a route from South Asia through Indochina, Sulawesi and hence Flores is tentatively supported on the basis of zoogeography. With regards to the second question, we find the archaeological record equivocal. A basic energetics model shows that a greater number of small-bodied hominins could persist on Flores than larger-bodied hominins (whether H. floresiensis is a dwarfed species or a descendent of an early small-bodied ancestor is immaterial here), which may in part explain their apparent long-term success. Yet the frequent tsunamis and volcanic eruptions in the region would certainly have affected all the taxa on the island, and at least one turnover event is recorded, when Stegodon sondaari became extinct. The question of the likelihood of persistence may be unanswerable until we know much more about the biology of H. floresiensis

Tropical forests and the genus Homo

Tropical forests constitute some of the most diverse and complex terrestrial ecosystems on the planet. From the Miocene onward, they have acted as a backdrop to the ongoing evolution of our closest living relatives, the great apes, and provided the cradle for the emergence of early hominins, who retained arboreal physiological adaptations at least into the Late Pliocene. There also now exists growing evidence, from the Late Pleistocene onward, for tool-assisted intensification of tropical forest occupation and resource extraction by our own species, Homo sapiens. However, between the Late Pliocene and Late Pleistocene there is an apparent gap in clear and convincing evidence for the use of tropical forests by hominins, including early members of our own genus. In discussions of Late Pliocene and Early Pleistocene hominin evolution, including the emergence and later expansion of Homo species across the globe, tropical forest adaptations tend to be eclipsed by open, savanna environments. Thus far, it is not clear whether this Early-Middle Pleistocene lacuna in Homo-rainforest interaction is real and representative of an adaptive shift with the emergence of our species or if it is simply reflective of preservation bias.For financial support, we acknowledge the Natural Environmental 314 ARTICLE Research Council (no. 1322282 to PR), the Boise Fund (to PR), the European Research Council (no. 206148 to NB, no. 617627 to JS, no. 295719 to MP), and the Leakey Foundation (to JLT)

Sur les premiers peuplements du Pacifique sud

Le Pacifique sud regroupe l\u27Australie et les îles du Pacifique : Mélanésie, Micronésie, Polynésie. Quelles populations les ont peuplées ? Quand, pourquoi et comment ? D\u27où venaient-elles ? L\u27environnement a-t-il conditionné leurs déplacements ? Une discussion exhaustive de ces vastes problématiques ne saurait être entreprise rigoureusement dans le cadre de ce court article. Nous proposons donc plutôt de discuter ici certains points très précis, apportant un éclairage nouveau sur les premiers peuplements du Pacifique sud. Si l\u27on se réfère aux sites archéologiques les plus anciens d\u27Australie, l\u27arrivée des premiers Homo sapiens dans la région a pu se produire il y a au moins 40 000 ans, voire dès 50 à 60 ka BP. D\u27un point de vue paléoanthropologique, un débat existe depuis plusieurs années sur l\u27origine de ces hommes anatomiquement modernes : sont-ils issus d\u27une migration hors d\u27Afrique relativement récente (hypothèse de l\u27 Out of Africa) ou bien sont-ils les descendants directs des derniers Homo erectus indonésiens (hypothèse « multirégionale ») ? Plusieurs points fondamentaux opposent les partisans de ces deux hypothèses, en particulier l\u27interprétation de ressemblances morphométriques entre les H. erectus indonésiens les plus récents et les H. sapiens fossiles australiens dits « robustes » de Kow Swamp et Cohuna. L\u27application de méthodes de morphométrie géométrique en 3D (analyses Procruste) permet d\u27aborder cette problématique sous un angle nouveau. Les conformations de ces deux ensembles d\u27hominidés fossiles sont très clairement distinctes, permettant de mettre en doute l\u27hypothèse d\u27une filiation locale directe. Pour ces peuplements humains anciens et les migrations ultérieures, la confrontation et la comparaison des données paléoenvironnementales, archéologiques, paléoanthropologiques, génétiques et linguistiques permettent de reconstituer petit à petit les grandes lignes de l\u27histoire des premiers peuplements humains de ces régions. Climat et environnement ont interagi avec ces déplacements de populations. Le tout premier exemple en est la formation de ponts terrestres entre le continent Asiatique et l\u27archipel Indonésien lors des glaciations quaternaires, qui ont permis le passage des hommes et de la faune. C\u27est peut-être aussi à l\u27occasion de l\u27abaissement du niveau des mers, que la dispersion d\u27îles en îles a pu être favorisée. Vents et courants, directement liés au climat et à ses variations sont également intervenus dans le peuplement du Pacifique. L\u27environnement naturel, qui s\u27appauvrit d\u27ouest en est, a été enrichi des animaux et des plantes que les hommes transportaient avec eux. En fonction de leur mode de vie, mais aussi des ressources disponibles, ils ont occupé, dans un premier temps, la zone littorale (sites Lapita), puis, très vite, l\u27intérieur des terres, comme l\u27ont montré, entre autres, des fouilles réalisées en Nouvelle-Calédonie, dans le Nord de la Grande Terre.South Pacific includes Australia and the Pacific Islands: Melanesia, Micronesia, Polynesia. Which human populations settled them? When, why and how? Where did they come from? Did environment influence these migrations? An exhaustive discussion of these vast questions could not be undertaken rigorously within the framework of this short article. We thus propose to discuss here very precise points that could bring a new lighting on the first settlements of South Pacific. According to the oldest archaeological sites of Australia, first arrivals of Homo sapiens in the area occurred at least 40 000 years ago, and possibly as early as 50 to 60 ka BP. From a palaeoanthropological point of view, the question of the origin of these anatomically modern H. sapiens is under debate for several years: did they come from a relatively recent ‘out of Africa’ migration (Out-of-Africa hypothesis) or did they evolve locally from the last Indonesian H. erectus (multiregional hypothesis)? Partisans of these two models disagree on several fundamental points, and particularly on the interpretation of certain morphometric affinities between the most recent Indonesian H. erectus and the ‘robust’ Australian fossil H. sapiens from Kow Swamp and Cohuna. The application of 3D geometric morphometrics (Procrustes analysis) makes it possible to approach this question under a new angle. The shapes of these two sets of fossil hominids are clearly distinct, questioning seriously the assumption of a local direct evolution. For these oldest human settlements as well as for later migrations, multidisciplinary studies (archaeology, palaeoenvironment, palaeoanthropology, genetic, and linguistic) allow us to reconstruct the outlines of the first human settlements of these areas. Climate and environment interacted with these migrations of populations. The very first example is the formation of land bridges between Asian mainland and the Indonesian archipelago during Quaternary glaciations allowing the passage of humans and fauna. And periods of lower sea levels possibly also favoured dispersion from islands to islands. Winds and sea currents, directly related with climate and its variations, also intervened in the settlement of the Pacific. Natural environment, which is impoverished eastward, has been enriched by animals and plants transported by humans. In relation to their way of life as well as to available resources, peoples initially settled littoral zones (Lapita sites), then moved inland very quickly, as demonstrated by excavations carried out in the North of Grande Terre, New Caledonia.</p