Crocodilian remains from the late Palaeocene continental locality of Mont de Berru (Marne, France) offer the opportunity to reassess the taxonomic identity of the oldest diplocynodontid from Europe. Owing to significant morphological differences from previously described species of Diplocynodon, which include the presence of a splenial symphysis, a new species, Diplocynodon remensis sp. nov., is erected here. Its inclusion in a phylogenetic framework for Eusuchia leads to its positioning as a derived member of diplocynodontids. Diplocynodontidae are viewed as a basal alligatoroid taxon, and, because morphological affinities with the Late Cretaceous−early Eocene North American genus Borealosuchus were mentioned in earlier studies, a comparison amongst D. remensis sp. nov., Leidyosuchus, and Borealosuchus spp. is presented. Although D. remensis sp. nov. is the geologically oldest diplocynodontid, according to our results, it is not the phylogenetically most primitive. Other morphological discrepancies are highlighted, indicating that the topology recovered here is only tentative. From a biogeographical point of view, the appearance of Diplocynodon in Europe prior to the Palaeocene/Eocene boundary indicates that it did not disperse with North American taxa that reached Europe around the time of the Palaeocene-Eocene thermal maximum (PETM). Therefore, a pre-PETM dispersal from North America at the same times as other vertebrates with clear North American affinities also occurring in the Palaeocene of Europe cannot be excluded. The description of D. remensis sp. nov. adds substantial new, albeit conflicting, information, highlighting the need for a better phylogenetic framework with a revision of other critical taxa (Menatalligator, Borealosuchus) from the Palaeocene of Europe and North America.
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Although questions of modern human origins and dispersal are subject to intense research within and outside Africa, the processes of modern human diversification during the Late Pleistocene are most often discussed within the context of recent human genetic data. This situation is due largely to the dearth of human fossil remains dating to the final Pleistocene in Africa and their almost total absence from West and Central Africa, thus limiting our perception of modern human diversification within Africa before the Holocene. Here, we present a morphometric comparative analysis of the earliest Late Pleistocene modern human remains from the Central African site of Ishango in the Democratic Republic of Congo. The early Late Stone Age layer (eLSA) of this site, dated to the Last Glacial Maximum (25–20 Ky), contains more than one hundred fragmentary human remains. The exceptional associated archaeological context suggests these remains derived from a community of hunter-fisher-gatherers exhibiting complex social and cognitive behaviors including substantial reliance on aquatic resources, development of fishing technology, possible mathematical notations and repetitive use of space, likely on a seasonal basis. Comparisons with large samples of Late Pleistocene and early Holocene modern human fossils from Africa and Eurasia show that the Ishango human remains exhibit distinctive characteristics and a higher phenotypic diversity in contrast to recent African populations. In many aspects, as is true for the inner ear conformation, these eLSA human remains have more affinities with Middle to early Late Pleistocene fossils worldwide than with extant local African populations. In addition, cross-sectional geometric properties of the long bones are consistent with archaeological evidence suggesting reduced terrestrial mobility resulting from greater investment in and use of aquatic resources. Our results on the Ishango human remains provide insights into past African modern human diversity and adaptation that are consistent with genetic theories about the deep sub-structure of Late Pleistocene African populations and their complex evolutionary history of isolation and diversification.
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RBINS Staff Publications 2016
