Vol.:(0123456789) 1 3 Archaeological and Anthropological Sciences (2021) 13:178 https://doi.org/10.1007/s12520-021-01437-7 ORIGINAL PAPER Palimpsest of micromammal deposits in an archaeological rock shelter (Álvarez 4, Late Holocene) from northwestern Patagonia, Argentina Ailín A. Guillermo 1,2  · Claudia I. Montalvo 3  · Fernando J. Fernández 1,4 Received: 15 April 2021 / Accepted: 30 August 2021 © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2021 Abstract This study provides a taphonomic and paleoenvironmental analysis of the micromammal (<1 kg) accumulations from the archaeological site Álvarez 4 (AZ4), a rock shelter located at the middle basin of the Limay River, Río Negro Province, northwestern Patagonia, Argentina. Based on taphonomic and taxonomic features, several skeletal remains accumulated in Period I (963 cal. BP), Period II (187 cal. BP), and square C3 (963 cal. BP) are assigned to the action of Strigiformes, while pellets found in the surface layer (SL) (187 cal. BP) would have been deposited by Accipitriformes. Pellet bones were more protected from trampling than bones recovered from the sieved sediments of the SL. In addition, some Caviidae remains from Period II and square C3 were likely incorporated in human consumption. This low-ranked resource might have complemented the otherwise high-ranked animals found in Álvarez 4, which would suggest a similar diet breadth to that frequently seen at several archaeological sites in the area. The paleoenvironmental analysis based on the small mammals recovered from AZ4 shows the development of open areas of shrubby-grassy Patagonian steppe and large rocky outcrops with overall stability of habitats, with a dominance of shrublands and steppes in the last ~1000 years. Past environments were more heterogeneous than today, as evidenced by the absence of some species and the expansion of opportunistic species in the modern pellet samples near to the rock shelter. Keywords Taphonomy · Paleoenvironment · Pellets · Faunistic resources · Late Holocene · Limay Basin Introduction Most of the Quaternary small mammal remains from the Limay River, Río Negro Province, northwestern Patagonia come from archaeological sites (e.g., Andrade and Boschín 2015; Ceballos 1982; Crivelli Montero et al. 1996; Fernández et al. 2016, 2018; Guillermo et al. 2020a, b; Hajduk and Albornoz 1999; Massoia 1982, 1987; Pardiñas 1999a, b; Pardiñas and Teta 2013; Pearson 1987; Pearson and Pearson 1993; Tammone et al. 2014, 2020; Teta et al. 2005). The oldest records of micromammals from this area were found at basal levels (sterile from the archaeological point of view) dated toward the end of the Late Pleistocene, during the Last Glacial Maximum (Tammone et al. 2014). However, most fndings of micromammals are associated with the Holocene, especially toward its end (Crivelli Montero et al. 1996; Fernández et al. 2016; Pardiñas 1999a; Pardiñas and Teta 2013; Pearson 1987; Pearson and Pearson 1993; Teta et al. 2005). This temporal distribution of the micromammal findings is coincident with the peopling of the area. The oldest dating associated with humans corresponds to the Pleistocene-Holocene transition. The human populations increase up to ca. 6200 14 C BP; then, they decrease sharply between ca. 5000 and 3000 14 C BP, and fnally they grow steadily since 3000 14 C BP (e.g., Boschín 2009; Crivelli Montero 2010; Crivelli Montero et al. 1993, 1996; Hajduk et al. 2006, 2007). * Ailín A. Guillermo ailin.guillermo@gmail.com 1 GEArq – CONICET, Grupo de Estudios en Arqueometría, Facultad de Ingeniería, UBA, Av. Paseo Colón, 850 Buenos Aires, Argentina 2 CIAFIC – CONICET, Centro de Investigaciones en Antropología Filosófca y Cultural, Av. Federico Lacroze, 2100 Buenos Aires, Argentina 3 Facultad de Ciencias Exactas y Naturales, UNLPam, Uruguay 151, Santa Rosa, La Pampa, Argentina 4 Facultad de Ciencias Naturales y Museo, UNLP, Calle 64 s/n entre diagonal 113 y calle 120, La Plata, Buenos Aires, Argentina