Time and Origin of Cichlid Colonization of the Lower Congo Rapids

Most freshwater diversity is arguably located in networks of rivers and streams, but, in contrast to lacustrine systems riverine radiations, are largely understudied. The extensive rapids of the lower Congo River is one of the few river stretches inhabited by a locally endemic cichlid species flock as well as several species pairs, for which we provide evidence that they have radiated in situ. We use more that 2,000 AFLP markers as well as multilocus sequence datasets to reconstruct their origin, phylogenetic history, as well as the timing of colonization and speciation of two Lower Congo cichlid genera, Steatocranus and Nanochromis. Based on a representative taxon sampling and well resolved phylogenetic hypotheses we demonstrate that a high level of riverine diversity originated in the lower Congo within about 5 mya, which is concordant with age estimates for the hydrological origin of the modern lower Congo River. A spatial genetic structure is present in all widely distributed lineages corresponding to a trisection of the lower Congo River into major biogeographic areas, each with locally endemic species assemblages. With the present study, we provide a phylogenetic framework for a complex system that may serve as a link between African riverine cichlid diversity and the megadiverse cichlid radiations of the East African lakes. Beyond this we give for the first time a biologically estimated age for the origin of the lower Congo River rapids, one of the most extreme freshwater habitats on earth

Géodynamique andine : résumés étendus = Andean geodynamics : extended abstracts

Les bassins transportés de la zone sub-andine de Bolivie sont caractérisés par des phénomènes tectoniques, sédimentaires et érosifs qui agissent simultanément. Pour étudier l'interaction entre ces phénomènes et mieux comprendre l'évolution géodynamique de la zone sub-andine, des modélisations ont été réalisées. Des expériences analogiques impliquant la déformation de modèles en sable-silicone, et leur visualisation au scanner médical ont été effectuées à l'IFP, tandis que des modèles cinématiques directs incorporant l'érosion ont été réalisés grâce à des procédures numériques. Il apparaît que les développements des bassins transportés au nord de la Bolivie et ceux du sud semblent sensiblement différents. (Résumé d'auteur

Palaeozoic orogeneses around the Siberian craton: Structure and evolution of the Patom belt and foredeep

International audienceThis paper sheds light on the evolution of the Patom belt. This mountain range draws an arc along the southeastern edge of the Siberian craton. It is supposed to be of Caledonian age and to result from the accretion of microcontinents against the craton, but up to now, its detailed stratigraphic and tectonic history was unclear. A field study allows us to clarify it. The sedimentary record is marked by a slow evolution with stable periods of more than 250 Ma. The observed sedimentary succession confirms the existence of a passive margin setting in the late Riphean (900 Ma), followed during the Vendian (650-600 Ma) by the obduction of the Baikal-Muya ophiolites belt and a foredeep inversion. After that, a Late Cambrian extension occurred, which is first described in this paper. The second collision stage occurred after 385 Ma, in the Late Devonian-Early Carboniferous. Sedimentary and tectonic data are interpreted in the light of the geodynamic evolution of Siberia, which is dominated by continental collages against the Siberian craton. Field data reveal a homogeneous direction of compression from the inner areas to the foreland. Whereas the inner range displays metamorphosed units deformed in the ductile domain, deformation is weaker in the foreland, which developed above the cratonic crust.We relate this high deformation gradient to the presence of the stiff craton which impeded strain propagation. The irregular shape of the craton as well as preexistent basement topography can explain the different tectonic styles observed along the belt

Tectonic versus lithospheric origins of the relief of the Atlas Mountains of Morroco

International audienc

Erratum: Seismic hazard reappraisal from combined structural geology, geomorphology and cosmic ray exposure dating analyses: The Eastern Precordillera thrust system (NW Argentina) (Geophys. J. Int. vol. 150 (241-260))

cited By 3International audienceno abstrac

Recent sedimentary processes along the Makran trench (Makran active margin, off Pakistan)

Nicolas Mouchot, Lies Loncke, Geoffroy Mahieux, Julien Bourget, Siegfried Lallemant, Nadine Ellouz-Zimmermann and Pascale Leturmyhttp://www.elsevier.com/wps/find/journaldescription.cws_home/503350/description#descriptio