Conference Presentations & Posters
The NEDEMO project is a network of pluridisciplinary research aiming at iden fying the demographi... more The NEDEMO project is a network of pluridisciplinary research aiming at iden fying the demographic parameters (ferr lity, survival, structure and varia on in the size of the popula on) that resulted in Neandertal demise. Three scenarios have been proposed: • Modern humans replaced Neandertals in Europe; • Modern humans assimilated the Neandertal popula on; • Modern humans replaced and partly assimilated Neandertals. To determine which of the three proposed scenarios is most likely, we will use an approach based on demographic modeling, which is widely employed in ecology for the study of the dynamics of animal populaa ons. As in all modeling work, we will simplify and interlink biological, social and environmental processes that may explain the disappearance of the Neandertals. This approach will also enable us to test diff erent hypotheses and, in addii on, to determine the value of a priori parameters that are not measurable. To model the past popula on dynamics of Neandertals, we use the Leslie matrix which requires knowledge of the survival and the ferr lity rates for each age group from birth to 50 years-old. Although the Neandertal demographic parameters are not known with precision, they can be inferred through the integra on of data provided by other disciplines and by compara ve analyses. First results. It is not necessary to infer dras c demographic changes. Very small diff erences in ferr lity or in survival rates may cause enormous diff erences over a period of ten thousand years in total popula on size and they can also account for ex ncc on. We aim to design models of popula on gene cs to test whether Modern humans (MHS) have assimilated the Neandertal popula on (HN) or not. Analysis of three models of admixture, with varying demographic parameters, will allow quan fi caa on of three possible sources of HN contribuu on: (i) a sole instantaneous event in Middle-East at-50Ka; (ii) an introgression in Middle-East at-100Ka, then a backward migra on of admixed MHS in Africa, followed by a peopling of Europe and Asia (founder eff ect + possible admixture during expansion); (iii) a long term sex-biased gene fl ow during MSH expansion (mtDNA, which is maternally transmii ed, does not support an admixture). ! Available mammalian fossil datasets (e.g. Paleobiology database; pers. data) will provide a palaeological framework including structural proxies such as diversity, body size/ mass, diet and habitat, in order to iden fy their possible interacc ons in the framework of Neandertal popula on dynamics. Starr ng from well documented faunal units in me and space, the main clima c shii s (e.g. GIPS2 pulses) will also be integrated and cons tute the background of this palaecological analysis. One of the main challenges presented by this work will be to link key environmental changes to the Neandertal popula on in the limited me-scale of the last part of the Upper Pleistocene. The project's fi rst step involves the design and implementa on of a complex rela onal database employing quan taa ve and qualita ve data useful for iden fying rela onships between diff erent data sources. It will be easy for all the members of the consorr um to use this database. At present, researchers involved in the project come from anthropobiology, gene cs, ecology, paleoanthropology, and archeozoology. We hope to s mulate interest in this project among researchers in view of presen ng a broader interna onal project. This work has been produced within the framework of the Unit of Excellence LabexMed –Social Sciences and Humanii es at the heart of mull disciplinary research for the Mediterranean –which holds the following reference 10 – LABX-0090. This work has benefi ted from a state grant administered by the Agence Na olane de la Recherche for the project Inves ssements d'Avenir A*MIDEX which holds the reference n° ANR-11-IDEX-0001-02
Bookmarks Related papers MentionsView impact
Papers
Quaternary International, 2015
ABSTRACT During the course of archaeological test excavations carried out in 2007 in the cave of ... more ABSTRACT During the course of archaeological test excavations carried out in 2007 in the cave of Bizmoune (Essaouira region, Morocco), seven archaeological layers yielding Pleistocene and Holocene artefacts and faunal remains were identified. In the layers C4, C3 and C2, respectively from the oldest to the most recent, terrestrial Helicidae mollusk shells (Helix aspersa) were dated by 14C. These layers also contained many fragments of eggshell, belonging to Struthio cf. camelus, associated with mammal remains such as Oryctolagus/Lepus, Gazella sp., Sus scrofa, Ammotragus lervia, Alcelaphus buselaphus, Equus sp., Phacochoerus aethiopicus and an undetermined Caprini. Among these remains, an incomplete mandible of Megaceroides algericus Lydekker, 1890 with M1 and M2 was found in layer C3. The 6641 to 6009 cal BP time range attributed to this layer has provided the most recent date known so far for M. algericus. In this study, we review and contextualize the findings of this particular species both in time and space and discuss its systematic position. We describe the morphology of the typical pachyostosic mandibular bone with the teeth and compare the dimensions with existing data. The assumption of the combined development, on the one hand, of the pachyostosic phenomenon and on the other hand, of the body weight fluctuations and growth of antlers for cervids strongly affected by seasonality is not supported. In order to understand the origin and the extinction of M. algericus, we examined the AMS radiocarbon dates available in the literature and calibrated them with RenDateModel software. Comparisons are then made with sea surface temperatures (e.g. GISP2 δ18O), eustasy and related environmental changes throughout the time span of this species. Based on these data a possible migration route by the Strait of Gibraltar connected with with eustatic rises in sea-level rises are discussed. The speciation-extinction processes for M. algericus and their correlations with climatic shifts on a long time-scale in North Africa (e.g. Heinrich events, 8200 cal BP event) are also considered. Finally, this new discovery in Bizmoune cave clearly shows that M. algericus lasted until the very end of the Epipaleolithic, around 6000 cal BP (middle Holocene), whereas this species was formerly not believed to have survived until the early Epipaleolithic (around 8000 cal BP).
Bookmarks Related papers MentionsView impact
Uploads