Continental mammalian biozonation of the European and western Asian Plio-Pleistocene state of the art and repercussion on the Tertiary-Quaternary and Plio-Pleistocene boundaries - Biozonation continentale du Plio-Pleistocene dEurope et dAsie occidentale par les mammiferes etat de la question et incidence sur les limites Tertiaire/Quaternaire et Plio/Pleistocene
Quaternaire 181: 23-33
Principles of a mammalian biozonation for the Mediterranean Neogene of Europe were laid down by P. Mein in 1975. They were used since 1980 by C. Guerin to constitute a biozonation for the European Plio-Pleistocene. Each mammalian bio/one is a standardzone as conceived by J.H. Callomon, with isochronous boundaries. Such a standardzone complies with two principles, the one of contiguity (implying that the upper limit of a zone is generally defined by the lower limit of the following one) and the other of hierarchy (boundaries between stratigraphical units of one rank coincide with boundaries between units of the next lower rank). Each mammalian standardzone has a triple definition: presence of characteristic stages of evolutionary lineages (subspecies and species), presence of typical mammalian associations (genera and species), appearance of new taxa (genera and species). The MNQ system closely follows the advancement of the palaeontological knowledge: two examples of advances established during the last ten years for the Plio-Pleistocene of Europe are given. the one of the Proboscideans and the other of the Bovids. Such a system is a good tool for dating a site accurately when no radiochronological technology is usable. It easily and completely integrates the new radiometric results. It call alleviate the weaknesses recently appeared in some of the OIS data. If applied to a new definition of the Tertiary/Quaternary and Plio-Pleistocene boundaries, which. owing to the hierarchy principle. must he the same, the MNQ system militates in favour of a date of about 2.6 Ma. corresponding to the boundary between the MNQ 15 and 16 standard/ones. A similar limit appears in other palaeobiogeographical realms, for instance in Africa and South America. with a very important faunal change at the same time.