TAPHONOMIC ANALYSIS OF THE LATE PLEISTOCENE SMALL MAMMALS OF QUEQUEN SALADO RIVER, BUENOS AIRES, ARGENTINA. A taphonomic analysis was made on small mammal remains recovered from fossil bone accumulations, interpreted as whole and fragmented pellets, from Upper Pleistocene levels of the Quequen Salado River cliffs (Buenos Aires, Argentina). Additionally, the probable source of the accumulation and some features associated with post-burial preservation processes are discussed. From the available information it is possible, through analyzing the anatomical representation of the remains and the degree of digestion, to show affinities with extant accumulations produced by nocturnal birds of prey. Nevertheless, breakage patterns are biased in this association as it shows much higher values than in a recent analysis based on pellets of extant nocturnal raptors. Diagenetic bone fractures found in skeletal elements have probably hidden the fractures produced at the moment of predation. Microstructural characteristics of remains preserved in the pellets are indicative of good preservation indicating rapid burial. Associated remains, interpreted as originating from disassembled pellets, also may have been buried rapidly as they do not show any weathering. From a biostratigraphic point of view and based on the associated mammalian megafauna, this accumulation can be assigned to the Lujanian Stage/Age of the late Pleistocene.