PALEOECOLOGICAL FIRST RESULTS FROM THE MIDDLE PLEISTOCENE SEQUENCE OF COUDOULOUS I (QUERCY, LOT, FRANCE).

Abstract

The Coudoulous I (Lot, France) sequence has yielded abundant fossil associations dated to the end of the Middle Pleistocene. The total sample consists of 102 taxa corresponding to 75 species of mammals (53 small and 22 large mammals), 11 species of amphibians and 16 species of reptiles distributed in five faunal units (FUs). After evaluating the sample quality with completeness indices (CI and CIbda), we esta-blished rarefaction curves that were discussed at length together with Shannon-Wiener diversity (H’), Margalef species richness (D), and the Sørensen-Dice similarity index. In order to better understand structural changes in the mammal associations as well as the climate trends we built the body mass distribution with cenograms in the different FUs. Concurrently, we investigated the whole community using a more analy-tical approach with the “bioclimatic model” based on a climatic restriction index for each species to infer paleoclimatic proxies (i.e. tempera-tures, precipitation, aridity) and finally to assign each faunal unit to a dominant type of climate. Our results clearly indicate that the FUs could be systematically associated with a typical temperate climate with sub-Mediterranean temperate species for the largest part of the sequence, which is consistent with the dates obtained (U/Th, ESR/U-series, TT-OSL) and Marine Isotope Stage 7. Nevertheless, cold elements from a Boreal type climate component were also found in the sequence indicating possible climate oscillations in FUs. The upper part of the strati-graphy (FUII) is probably related to MIS 6 while the lowest part of the sequence (FUVII) could correspond to a cold phase of the MIS 7 or earlier (MIS 8?).