Biochronology and biochron boundaries: A real dilemma or a false problem? An example based on the Pleistocene large mammalian faunas from Italy

摘要: Abstract Reconstructing the Neogene-Quaternary biostratigraphy in continental environments and recognising ‘boundaries’ between successive mammalian faunal complexes is a problematic task. The definition application of biochronology has been often tainted by references to inferences from biostratigraphy. Actually, discontinuities sedimentary record, environmental conditions, taphonomic sampling biases are responsible for fact that stratigraphical order lowest highest occurrences fossil remains (stratigraphic datum) does not necessarily reflect temporal actual first/last appearances taxa (palaeobiological events) time. Nonetheless, appearance bioevents (recorded lowest/highest fossiliferous levels different successions) have principal foundation establishing biochronological setting mammal faunas. Therefore, theoretical point view, should be defined oldest and/or youngest ‘historical occurrence’ one or more taxa. What about an operational approach? Some examples Italian faunas presented, focusing on transition Villafranchian Galerian Aurelian Land-Mammal Ages. results obtained indicate difficulty defining stable scheme can applied correlation international scientific community.