Benthic Foraminifera from the Langhian of the Aquitaine Basin (SW France);palaeoecological and biogeographical data.

Thanks to systematic field samplings in the Aquitaine Basin, stratigraphic revisions and micropaleontological investigations allowed to recognize nume rous Langhian deposits referred to the planktonic zones N8-N9 (foraminifera ) and NN5 (nannofossils). The study of benthic foraminifera, which were til l now broadly unrecognized, exhibits a noticeable diversification, since mo re than 250 taxa have been found in all. This microfauna can be considered as a reference one for the Langhian of Western Europe. All the outcrops dis play platform facies, with significant differences according to the areas: lagoonal (brackish) to littoral environments in the central Aquitaine gulf (about 125 species), and marry deposits in deeper and quieter environments in the Saubrigues gulf (richer assemblage including more than 220 taxa). Se veral taxa are observed for the first time in the Aquitaine Basin, such as the genera Aubignyna, Haynesina, Chrysalidinella, Bisaccium, Chrysalogonium , and also Elphidium gr. excavatum, E. reussi, etc. Besides, it is interest ing to note the frequency of Pseudoeponides pseudotepidus miocenicus in the central Aquitaine. Numerous systematic remarks are made. Climatic data ind icate that the marine superficial waters were globally warm, but less than during the Burdigalian. As far as biogeography is concerned, comparisons wi th the Mid Miocene of Western France show chiefly qualitative similarities which clearly evidence good marine connections. However, inventories of the Ligerian Gulf microfaunas (as well as the Western Mediterranean ones) rema in still incomplete.