Recent benthic foraminifers on the continental shelf south of Dakar (Senegal).

Two hundred and twenty four benthic foraminiferal species were recognized in the total assemblages of fifty samples collected from the Senegalese continental shelf south of Dakar (down to a depth of 200 m). A factor analysis based on nineteen dominant species shows three main factors. The first two seem to be associated with temperature and its seasonal variations; they are depth-related and determine two main faunal changes. The third factor is substrate-related. The main depth-related species are: i) Cribrononion gerthi, Quinqueloculina akneriana, Quinqueloculina lamarckiana, Cribrolinoides curtus, Elphidium fichtellianum and Textularia sagittula in th coastal zone; ii) Discorbinella bertheloti, Cancris aff. C. sagrum, Textularia truncata, Nonion fabum, Bulimina elegans and Hanzawaia solei in the inner shelf; iii) Trifarina bradyana, Trifarina Fornasinii, Uvigerina peregrina and Cassidulina laevigata in the outer shelf. The species that are substrate-related are: i) N. fabum, B. elegans, C. gerthi and H. solei in the fine-grained sands and ii) Lobatula lobatula, C. curtus, T. sagittula and D. bertheloti in the coarse-grained sands. The reduction in planktonic percentage and diversity in the outer shelf are related to the upwelling seasonal influence. (C) Elsevier, Paris / Ifremer / Cnrs / Ird.