The oldest Camelidae (Mammalia, Artiodactyla) of Africa : new finds from the Mio-Pliocene boundary,Chad

Un fragment de mandibule et deux métapodes complets provenant du secteur fossilifère de Kossom Bougoudi (KB3 et KB26), Nord Tchad sont décrits. Une étude comparative permet d’attribuer les spécimens à Paracamelus gigas. Le degré évolutif des spécimens est compatible avec l’âge biochronologique des sites KB, proche de la limite Mio-Pliocène (ca 5 Ma). Les témoins les plus anciens du genre sont connus dans le Miocène supérieur d’Asie et d’Europe. Les restes tchadiens sont donc les plus anciens du continent attribués au genre

Structural and electronic properties of Cu4O3 (paramelaconite): the role of native impurities

Hybrid density functional theory has been used to study the phase stability and formation of native point defects in Cu4O3. This intermediate copper oxide compound, also known as paramelaconite, was observed to be difficult to synthesize due to stabilization issues between mixed-valence Cu1+ and Cu2+ ions. The stability range of Cu4O3 was investigated and shown to be realized in an extremely narrow region of phase space, with Cu2O and CuO forming readily as competing impurity phases. The origin of p-type conductivity is confirmed to arise from specific intrinsic copper vacancies occurring on the 1+ site. Away from the outlined stability region, the dominant charge carriers become oxygen interstitials, impairing the conductivity by creating deep acceptor states in the electronic band gap region and driving the formation of alternative phases. This study further demonstrates the inadequacy of native defects as a source of n-type conductivity and complements existing experimental findings

Chem4Energy: a consortium of the Royal Society Africa Capacity-Building Initiative

The Africa Capacity-Building Initiative is a Royal Society programme funded by the former UK Department for International Development to develop collaborative research between scientists in sub-Saharan Africa and the UK. Initially, four institutions were involved in the Chem4Energy consortium: Cardiff University in the UK and three African partners, the Kwame Nkrumah University of Science and Technology, Ghana, the University of Namibia and the University of Botswana, soon also including the Botswana International University of Science and Technology. The Chem4Energy research programme focused on ‘New materials for a sustainable energy future: linking computation with experiment’, aiming to deploy the synergy between state-of-the-art computational and experimental techniques to design and optimize new catalysts and semiconductor materials for renewable energy applications, based on materials that are abundant and readily available in African countries. The Chem4Energy consortium has achieved ambitious research goals, graduated seven PhD students and delivered a high-quality cross-disciplinary training programme in materials science and simulation techniques relevant to renewable energy applications. Since 2021, the extended consortium, including North-West University and the Centre for High-Performance Computing in South Africa, has remained active through an annual Chem4Energy conference series, with the sixth meeting taking place in Namibia in April 2025

The Age of the Sahara Desert

International audienc

Description and palaeobiology of a new species of Libycosaurus (Cetartiodactyla, Anthracotheriidae) from the Late Miocene of Toros-Menalla, northern Chad

International audienceThe analysis of a large sample of anthracothere remains discovered by the Mission Paléoanthropologique Franco-Tchadienne at Toros-Menalla (TM), Northern Chad, has revealed the occurrence of a single species with a large intraspecific morphological variability. Taxonomic problems triggered the necessity of naming a new species for the TM anthracotheres, Libycosaurus bahri sp. nov. The description of the craniodental remains and the analysis of their variability indicate a marked sexual dimorphism, most probably induced by sex differential growth, helping to reassess the specific diversity of Libycosaurus and its main evolutionary trends in a phylogenetic perspective. The ecological niche occupied by the new species was also further characterized in its semiaquatic, behavioural, and dietary dimensions. On these grounds we suggest that Late Miocene environmental changes, particularly habitat opening and hydrographic network fragmentation related to increased aridity, played a major role in canalizing semi-aquatic specializations and the extinction of the last African anthracotheres, as well as other bothriodontines

Phytoliths indicate significant arboreal cover at Sahelanthropus type locality TM266 in northern Chad and a decrease in later sites

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Application of the authigenic Be-10/Be-9 dating method to continental sediments : reconstruction of the Mio-Pleistocene sedimentary sequence in the early hominid fossiliferous areas of the northern Chad Basin

The concentrations of atmospheric cosmogenic Be-10 normalized to the solubilized fraction of its stable isotope Be-9 have been measured in the authigenic phase leached from silicated continental sediments deposited since the upper Miocene in the northern Chad Basin. This method is validated by the systematic congruence with the biochronological estimations based on the fossil mammal evolutive degree of faunal assemblages. The fifty-five authigenic Be-10/Be-9 ages obtained along 12 logs distributed along two West-East cross sections that encompass best representative Mio-Pliocene outcrops including paleontological sites show a systematic stratigraphic decrease when considering all studied sedimentary fades extending from the Pleistocene up to 8 Ma and allow performing geologic correlations otherwise impossible in the studied area. The resulting global sequence evidences and temporally specifies the succession of the main paleoenvironments that have developed in this region since the Miocene. Under the special conditions encountered in the northern Chad Basin, this study demonstrates that the authigenic Be-19/Be-9 ratio may be used as a dating tool of continental sedimentary deposits from 1 to 8 Ma. The half-life of Be-10 theoretically allowing dating up to 14 Ma, it may have fundamental implications on important field research such as paleoclimatology and, through the dating of fossiliferous deposits in paleontology and paleoanthropology