Introduction

International audienceIn the prospect of the COP21 held in Paris in December 2015, the French Centre for Ethiopian Studies (CFEE) organised a scientific conference on environmental and climatic changes in the horn of Africa, with a decisive financial support of the Institut français (Fonds d’Alembert), Paris. The conference was part of a larger event, called “the Road to Paris” and organised by the French Embassy to Ethiopia and the Horn of Africa Regional Environment Centre and Network (HoA-REC&N), Addis Ababa University, in HoA-REC&N headquarters at Gullele Botanic Gardens, Addis Ababa, from 7 to 9 April 2015.In this event, our first purpose was to set aside from the pressure of short-term and policy-oriented concerns raised by the international bureaucracies and bilateral donors, as to try to explore diverse, cross-disciplinary dimensions related to environmental change in the region in a wider way, wider in time and also wider in the elements observed. In a way, the Road to Paris event has also showed, with the various stakeholders and speakers it has gathered, that the issue of climate change has “solidified” automatic discourses, supporting wishful intentions and thinking, and clearly embedded in the building of professional opportunities and international careers. These discourses, indeed, are everything but close to the reality observed on the ground.In this new, competitive, social field, priority may not be easily given to scientific exploration that is not directly policy-oriented and that requires a longer time to produce strong data than what the political and bureaucratic agendas allow. One could not state, though, that interest for science is totally absent in these arenas on climate change. But, invariably, public expectations appear to be much too high in scope and in time, compared to what intellectual curiosity and scientific processes and protocols can produce on a day-to-day basis. Improving awareness on environmental changes should start here: to give a better understanding on the complexity and multiplicity of factors involved in the relation between human evolution, societal choices and developments, and natural environments. The French Centre for Ethiopian Studies (CFEE) in Addis Ababa was quite well equipped to initiate, with its partners, such a cross-disciplinary exploration

Climatic and Environmental Challenges: Learning from the Horn of Africa

In the prospect of the COP21 held in Paris in December 2015, the French Centre for Ethiopian Studies (CFEE) organised a scientific conference on environmental and climatic changes in the horn of Africa, with a decisive financial support of the Institut français (Fonds d’Alembert), Paris. The conference was part of a larger event, called “the Road to Paris” and organised by the French Embassy to Ethiopia and the Horn of Africa Regional Environment Centre and Network (HoA-REC&N), Addis Ababa Un..

Histoire évolutive du genre Kolpochoerus (Cetartiodactyla (Suidae) au Plio-Pléistocèneen Afrique orientale)

La sous-famille des Suinae est largement répandue en Afrique au Plio-Pléistocène et a été abondamment utilisée pour corréler biochronologiquement les sites à hominidés en se basant sur l'évolution morphologique rapide des troisièmes molaires dans différentes lignées. À partir d'un échantillon important de suinés africains actuels, les schémas de variation morphologique crânio-mandibulaire et dentaire sont quantifiés par morphométrie géométrique. Ce référentiel actuel sert à estimer la variabilité morphologique dans le registre fossile. La révision de la paléobiodiversité du genre Kolpochoerus (le suiné plio-pléistocène le plus abondant) dans les bassins du Turkana et de l'Awash s'appuie sur l'étude anatomique et morphométrique de matériels publié et inédit découverts dans la basse vallée de l'Omo (formation de Shungura) et dans la vallée moyenne de l'Awash en Éthiopie. Une nouvelle espèce fossile est décrite, les trajectoires évolutives au sein de chaque espèce sont quantifiées, et les interprétations biostratigraphiques sont révisées. Les liens de parenté au sein du genre Kolpochoerus sont décrits grâce à l'analyse cladistique. L'étude de la paléoécologie des suinés africains est basée sur l'anatomie comparée et la biogéochimie des isotopes stables (carbone et oxygène). Les suinés fossiles présentent une gamme de taille importante, ainsi que des régimes alimentaires et des habitats variés. Les nouvelles connaissances acquises sur leur biodiversité, leur phylogénie, et leur écologie permettent de proposer une histoire paléobiogéographique des Suinae en Afrique.The subfamily Suinae is widespread in Plio-Pleistocene deposits in Africa, and was heavily used as a biochronological tool to correlate hominid-bearing sites based on the rapid morphological evolution of third molars in different lineages. A large sample of extant African suines enables to quantify patterns of variation in cranio-mandibular and dental morphology using geometric morphometrics. This modern referential is used to estimate the morphological variability in the fossil record. Revision of the paleobiodiversity of the genus Kolpochoerus (the most abundant Plio-Pleistocene suine) in Turkana and Awash basins is based on anatomical and morphometric studies of published and unpublished material discovered in the Lower Omo Valley (Shungura Formation) and in the Middle Awash Valley in Ethiopia. A new fossil species is described, evolutionary trajectories within each species are quantified, and biostratigraphic interpretations are revised. Phylogenetic relationships within the genus Kolpochoerus are described by the cladistic analysis. Paleoecological study of African suines is based on comparative anatomy and stable isotopic biogeochemistry (carbon and oxygen). Fossil suines display a wide range of body size, as well as various diets and habitats. The new results produced regarding their biodiversity, phylogeny, and ecology, enable to reconstruct a paleobiogeographic history of Suinae in Africa.POITIERS-SCD-Bib. électronique (861949901) / SudocSudocFranceF

Histoire évolutive du genre Kolpochoerus (Cetartiodactyla (Suidae) au Plio-Pléistocèneen Afrique orientale)

La sous-famille des Suinae est largement répandue en Afrique au Plio-Pléistocène et a été abondamment utilisée pour corréler biochronologiquement les sites à hominidés en se basant sur l'évolution morphologique rapide des troisièmes molaires dans différentes lignées. À partir d'un échantillon important de suinés africains actuels, les schémas de variation morphologique crânio-mandibulaire et dentaire sont quantifiés par morphométrie géométrique. Ce référentiel actuel sert à estimer la variabilité morphologique dans le registre fossile. La révision de la paléobiodiversité du genre Kolpochoerus (le suiné plio-pléistocène le plus abondant) dans les bassins du Turkana et de l'Awash s'appuie sur l'étude anatomique et morphométrique de matériels publié et inédit découverts dans la basse vallée de l'Omo (formation de Shungura) et dans la vallée moyenne de l'Awash en Éthiopie. Une nouvelle espèce fossile est décrite, les trajectoires évolutives au sein de chaque espèce sont quantifiées, et les interprétations biostratigraphiques sont révisées. Les liens de parenté au sein du genre Kolpochoerus sont décrits grâce à l'analyse cladistique. L'étude de la paléoécologie des suinés africains est basée sur l'anatomie comparée et la biogéochimie des isotopes stables (carbone et oxygène). Les suinés fossiles présentent une gamme de taille importante, ainsi que des régimes alimentaires et des habitats variés. Les nouvelles connaissances acquises sur leur biodiversité, leur phylogénie, et leur écologie permettent de proposer une histoire paléobiogéographique des Suinae en Afrique.The subfamily Suinae is widespread in Plio-Pleistocene deposits in Africa, and was heavily used as a biochronological tool to correlate hominid-bearing sites based on the rapid morphological evolution of third molars in different lineages. A large sample of extant African suines enables to quantify patterns of variation in cranio-mandibular and dental morphology using geometric morphometrics. This modern referential is used to estimate the morphological variability in the fossil record. Revision of the paleobiodiversity of the genus Kolpochoerus (the most abundant Plio-Pleistocene suine) in Turkana and Awash basins is based on anatomical and morphometric studies of published and unpublished material discovered in the Lower Omo Valley (Shungura Formation) and in the Middle Awash Valley in Ethiopia. A new fossil species is described, evolutionary trajectories within each species are quantified, and biostratigraphic interpretations are revised. Phylogenetic relationships within the genus Kolpochoerus are described by the cladistic analysis. Paleoecological study of African suines is based on comparative anatomy and stable isotopic biogeochemistry (carbon and oxygen). Fossil suines display a wide range of body size, as well as various diets and habitats. The new results produced regarding their biodiversity, phylogeny, and ecology, enable to reconstruct a paleobiogeographic history of Suinae in Africa.POITIERS-SCD-Bib. électronique (861949901) / SudocSudocFranceF

A new species of hippopotamine (Cetartiodactyla, Hippopotamidae) from the late Miocene Baynunah Formation, Abu Dhabi, United Arab Emirates

The discovery of new hippopotamid material from the late Miocene Baynunah Formation (Abu Dhabi, United Arab Emirates) has prompted the revision of the existing material of this as yet unnamed fossil taxon. The Baynunah hippopotamid appears to be distinct from all other contemporary and later species in having a relatively more elongate symphysis, a feature similar to the earlier (and more primitive) Kenyapotamus. Yet, the Baynunah hippopotamid presents a dentition typical of the Hippopotaminae. It is therefore a distinct species attributed to the later subfamily, described and named in this contribution. This species provides further evidence for a ca. 8 Ma evolutionary event (termed “Hippopotamine Event”) that initiated the spread and ecological significance of the Hippopotaminae into wet habitats across Africa and Eurasia. The morphological affinities of the new species from Abu Dhabi suggest that the Arabian Peninsula was not a dispersal route from Africa toward southern Asia for the Hippopotamidae at ca. 7.5 Ma to 6.5 Ma

Increase on environmental seasonality through the European Early Pleistocene inferred from dental enamel hypoplasia

An in-depth study of the Early Pleistocene European remains of Hippopotamus has allowed the first detailed description of the incidence and types of dental alterations related to palaeopathologies and potentially linked to climatic and environmental factors. The results of a long-term qualitative and quantitative assessment highlight the importance of nutrient deficiencies on the development of dental enamel hypoplasia in Hippopotamus. Glacial cyclicity and the resulting changes in humidity and plant community structure conditioned the local environments critical for the survival of this taxon. Two main intervals of putative constrained nutritionally restrictions were detected at ca. 1.8 Ma and ca. 0.86 Ma (i.e., MIS63 and MIS21, respectively). Statistical comparisons show an increase in the frequency of dental hypoplasia between these two chronological periods, thus reinforcing the idea of increased seasonality in the circum-Mediterranean environments during the Early Pleistocene

Paleoecology of the Serengeti during the Oldowan-Acheulean transition at Olduvai Gorge, Tanzania : The mammal and fish evidence

Eight years of excavation work by the Olduvai Geochronology and Archaeology Project (OGAP) has produced a rich vertebrate fauna from several sites within Bed II, Olduvai Gorge, Tanzania. Study of these as well as recently re-organized collections from Mary Leakey's 1972 HWK EE excavations here provides a synthetic view of the faunal community of Olduvai during Middle Bed II at similar to 1.7-1.4 Ma, an interval that captures the local transition from Oldowan to Acheulean technology. We expand the faunal list for this interval, name a new bovid species, clarify the evolution of several mammalian lineages, and record new local first and last appearances. Compositions of the fish and large mammal assemblages support previous indications for the dominance of open and seasonal grassland habitats at the margins of an alkaline lake. Fish diversity is low and dominated by cichlids, which indicates strongly saline conditions. The taphonomy of the fish assemblages supports reconstructions of fluctuating lake levels with mass die-offs in evaporating pools. The mammals are dominated by grazing bovids and equids. Habitats remained consistently dry and open throughout the entire Bed II sequence, with no major turnover or paleoecological changes taking place. Rather, wooded and wet habitats had already given way to drier and more open habitats by the top of Bed I, at 1.85-1.80 Ma. This ecological change is close to the age of the Oldowan-Acheulean transition in Kenya and Ethiopia, but precedes the local transition in Middle Bed II. The Middle Bed II large mammal community is much richer in species and includes a much larger number of large-bodied species (>300 kg) than the modern Serengeti. This reflects the severity of Pleistocene extinctions on African large mammals, with the loss of large species fitting a pattern typical of defaunation or 'downsizing' by human disturbance. However, trophic network (food web) analyses show that the Middle Bed II community was robust, and comparisons with the Serengeti community indicate that the fundamental structure of food webs remained intact despite Pleistocene extinctions. The presence of a generalized meateating hominin in the Middle Bed II community would have increased competition among carnivores and vulnerability among herbivores, but the high generality and interconnectedness of the Middle Bed II food web suggests this community was buffered against extinctions caused by trophic interactions. (C) 2017 Published by Elsevier Ltd.Peer reviewe

Evidence of Strong Stabilizing Effects on the Evolution of Boreoeutherian (Mammalia) Dental Proportions

The dentition is an extremely important organ in mammals with variation in timing and sequence of eruption, crown morphology, and tooth size enabling a range of behavioral, dietary, and functional adaptations across the class. Within this suite of variable mammalian dental phenotypes, relative sizes of teeth reflect variation in the underlying genetic and developmental mechanisms. Two ratios of postcanine tooth lengths capture the relative size of premolars to molars (premolar–molar module, PMM), and among the three molars (molar module component, MMC), and are known to be heritable, independent of body size, and to vary significantly across primates. Here, we explore how these dental traits vary across mammals more broadly, focusing on terrestrial taxa in the clade of Boreoeutheria (Euarchontoglires and Laurasiatheria). We measured the postcanine teeth of N = 1,523 boreoeutherian mammals spanning six orders, 14 families, 36 genera, and 49 species to test hypotheses about associations between dental proportions and phylogenetic relatedness, diet, and life history in mammals. Boreoeutherian postcanine dental proportions sampled in this study carry conserved phylogenetic signal and are not associated with variation in diet. The incorporation of paleontological data provides further evidence that dental proportions may be slower to change than is dietary specialization. These results have implications for our understanding of dental variation and dietary adaptation in mammal

Paleoecology of the Serengeti during the oldowan-Acheulean transition at Olduvai Gorge, Tanzania: The mammal and fish evidence

Eight years of excavation work by the Olduvai Geochronology and Archaeology Project (OGAP) has produced a rich vertebrate fauna from several sites within Bed II, Olduvai Gorge, Tanzania. Study of these as well as recently re-organized collections from Mary Leakey's 1972 HWK EE excavations here provides a synthetic view of the faunal community of Olduvai during Middle Bed II at ~1.7e1.4 Ma, an interval that captures the local transition from Oldowan to Acheulean technology. We expand the faunal list for this interval, name a new bovid species, clarify the evolution of several mammalian lineages, and record new local first and last appearances. Compositions of the fish and large mammal assemblages support previous indications for the dominance of open and seasonal grassland habitats at the margins of an alkaline lake. Fish diversity is low and dominated by cichlids, which indicates strongly saline conditions. The taphonomy of the fish assemblages supports reconstructions of fluctuating lake levels with mass die-offs in evaporating pools. The mammals are dominated by grazing bovids and equids. Habitats remained consistently dry and open throughout the entire Bed II sequence, with no major turnover or paleoecological changes taking place. Rather, wooded and wet habitats had already given way to drier and more open habitats by the top of Bed I, at 1.85e1.80 Ma. This ecological change is close to the age of the Oldowan-Acheulean transition in Kenya and Ethiopia, but precedes the local transition in Middle Bed II. The Middle Bed II large mammal community is much richer in species and includes a much larger number of large-bodied species (>300 kg) than the modern Serengeti. This reflects the severity of Pleistocene extinctions on African large mammals, with the loss of large species fitting a pattern typical of defaunation or ‘downsizing’ by human disturbance. However, trophic network (food web) analyses show that the Middle Bed II community was robust, and comparisons with the Serengeti community indicate that the fundamental structure of food webs remained intact despite Pleistocene extinctions. The presence of a generalized meateating hominin in the Middle Bed II community would have increased competition among carnivores and vulnerability among herbivores, but the high generality and interconnectedness of the Middle Bed II food web suggests this community was buffered against extinctions caused by trophic interactions.Fieldwork by OGAP is authorized by the National Museum of Tanzania, Tanzanian Antiquities, and COSTECH, and the Ngorongoro Conservation Authority, and was funded by the NSF (BCS-0852292) and a European Research Council Starting Grant (283366). FB was supported by the German Research Foundation (DFG, grant number BI 1879/1-1). AS was funded by the LaScArBx (Universite de Bordeaux), a research program supported by the Agence Nationale de la Recherche, France (ANR-10-LABX-52), and a SYNTHESYS grant (DE-TAF-5741). SV was supported by a post-doctoral fellowship from the Alexander von Humboldt Foundation. LW was funded by the Swedish Research Council.Peer reviewe