Keyword: Buenos Aires province

El objetivo de este trabajo es reconstruir la historia de la distribución de los armadillos en la región pampeana, particularmente en la provincia de Buenos Aires. Se analizaron los registros de las especies de dasipódidos de 21 yacimientos arqueológicos y paleontológicos. Se registraron: Eutatus seguini, Chaetophractus villosus, C. vellerosus, Zaedyus pichiy, Tolypeutes matacus y Dasypus hybridus. Se realizaron las siguientes interpretaciones: 1) durante el Holoceno temprano se registra, principalmente en el sector de Tandilia y Área Interserrana, la asociación C. villosus – E. seguini, con el agregado de Z. pichiy. Los dasipódidos registrados sugieren condiciones ambientales áridas a semiáridas y, probablemente, temperaturas medias anuales inferiores a las actuales; 2) durante el Holoceno medio se mantiene la asociación C. villosus – Z. pichiy en el centro y sur de la provincia, con una probable retracción de T. matacus en el Área Interserrana y de Tandilia. Esta asociación no refleja el pulso húmedo y cálido propuesto por varios autores, sino un avance de las condiciones patagónicas; 3) el Holoceno tardío se caracteriza principalmente por la asociación C. villosus – Z. pichiy – D. hybridus. En el lapso 3000–1500 años antes del presente se registran, en el nordeste de la provincia, armadillos típicos de climas cálidos del norte (T. matacus y D. hybridus) junto con C. villosus. Contemporáneamente, en el Área Interserrana se mantendrían las condiciones patagónicas, reflejadas por la asociación C. villosus – Z. pichiy. Hacia 1500 años AP la asociación C. villosus – D. hybridus ya se ha instalado en el norte y este de la provincia, destacándose la ausencia de Z. pichiy. Hacia el sur se registra la transición hacia las condiciones templado-húmedas actuales, evidenciada por el avance de D. hybridus.

Distribution of the armadillos (Mammalia, Dasypodidae) in the pampean region (Argentine Republic) during the Holocene. Paleoenvironmental interpretations. Since their first records in the late Miocene (13 millon years) the armadillos constitute one of the principal components of the Pampean region mammal fauna. During the last 10000 years, the distribution of these species in the Pampean region underwent variations as a consequence of climatic and environmental changes. The goal of this paper is to establish the history of the armadillos distribution in the Pampean region, particularly in the Buenos Aires Province. The paleontological and archeological records of the different species are analized, within the paleoenvironmental schemes proposed for the late Pleistocene-Holocene in middle latitudes of Argentina. Twenty one archeological and paleontological sites were considered and the following taxa were recorded: Eutatus seguini (an extinct species) and Chaetophractus villosus, C. vellerosus, Zaedyus pichiy, Tolypeutes matacus and Dasypus hybridus (all living species). The following conclusions can be inferred: 1) During the early Holocene the association C. villosus – E. seguini, with the addition of Z. pichiy, is present in Tandilia and Interserrana areas. The armadillos recorded in this period suggest arid and semiarid environmental conditions and, probably, annual mean temperatures lower than the present ones. 2) During the middle Holocene the association C. villosus – Z. pichiy is still present in central and southern Buenos Aires Province, with a probable retraction of T. matacus in Tandilia and Interserrana areas. This association indicates an advance of the Patagonic conditions; it doesn’t show the warm and humid pulse pointed by other authors. 3) The record of the late Holocene is characterized mainly by the association C. villosus – Z. pichiy – D. hybridus. Between 3000–1500 years before present, armadillos typical of the northern warm climates (T. matacus and D. hybridus) along with C. villosus, are recorded in the northeast of the province. At the same time, Patagonic conditions are still present in the Interserrana Area, reflected by the presence of C. villosus – Z. pichiy. Around 1500 years before present, the association C. villosus – D. hybridus is already established in northern and eastern Buenos Aires, whereas Z. pichiy is absent. A transition toward the present humid-temperate conditions is recorded to the south; this is shown for the range expansion of D. hybridus.