The isotopic fingerprint of terrestrial gastropods has been increasingly used as a credible natural paleoenvironmental archive. Most published work has used this proxy at tropical and temperate latitudes of the Northern Hemisphere, and focused on entire-shell analysis. The present study provides entire-shell and intra-shell isotopic profiles to infer average and seasonal late Holocene environmental conditions in central Argentina (30°S). Shells of Plagiodontes daedaleus (Gastropoda: Odontostomidae) were retrieved from the Alero Deodoro Roca–Sector B site, one of the few archaeological sites in central Argentina rich in shells collected by pre-Hispanic hunter-gatherer groups. Ancient entire shells exhibited values that were ~2.5‰ higher in δ¹³C and ~1.8‰ higher in δ¹⁸O than modern individuals, pointing to higher abundance of C₄ plants and overall drier conditions (lower relative humidity and/or higher rain δ¹⁸O) during 4.5–1.7 cal. kyr BP than today, in agreement with published regional proxies. Intra-shell isotopic profiles suggest that modern and fossil specimens deposited their shells throughout two-to-three summer/winter cycles. Intra-shell δ¹⁸O values varied ~5‰, matching with the seasonal variation of rain δ¹⁸O values. The extent of seasonality was similar during 4.5–1.7 cal. kyr BP and today. Intra-shell δ¹³C values varied ~2–3‰ and did not portray distinct seasonal cycles, depicting minimal seasonal variations in the snail diet. This work illustrates that South American terrestrial gastropods have great potential for paleoenvironmental studies.

Guanacos (Lama guanicoe) are large ungulates that have been valued by human populations in South America since the Late Pleistocene. Even though they were very abundant until the end of the 19th century (before the high deforestation rate of the last decades), guanacos have nearly disappeared in the Gran Chaco ecoregion, with relicts and isolated populations surviving in some areas, such as the shrubland area near the saline depressions of Córdoba province, Argentina. In this report, we present the first data from a locally endangered guanaco wild population, through the study of skeletal remains recovered in La Providencia ranch. Our results showed that most of the elements belonged to adults aged between 36 and 96 months; sex evaluation showed similar numbers of males and females. Statistical analysis of the body size of modern samples from Córdoba demonstrated that guanacos from the Chaco had large dimensions and presented lower size variability than the modern and archaeological specimens in our database. Moreover, they exhibited dimensions similar to those of modern guanacos from Patagonia and San Juan, and to archaeological specimens from Ongamira and Cerro Colorado, although further genetic studies are needed to corroborate a possible phylogenetic relationship. Finally, we used archaeozoological techniques to provide a first characterization of a relict guanaco population from the Chaco ecoregion, demonstrating its value to the study of modern skeletal remains and species conservation biology.

Los gasterópodos del sector B del sitio alero deodoro roca, Valle de Ongamira (Córdoba, Argentina): un análisis preliminar

El objetivo de este trabajo consistió en identificar las principales especies animales que actúan sobre carcasas de ungulados de gran porte en un área cercana al extremo austral de las Salinas Grandes de Córdoba y su potencial como agentes tafonómicos, considerando variables ecológicas como etología, competencia y posición en la cadena trófica. Con este fin, se realizaron tres monitoreos con cámaras trampa sobre carcasas de Bos taurus y Lama guanicoe. Además, se efectuaron observaciones preliminares sobre desarticulación, dispersión y trazas generadas por distintos agentes tafonómicos sobre las carcasas, a fin de contribuir a nuestro entendimiento sobre los procesos naturales de formación de conjuntos zooarqueológicos en la región. Los monitoreos permitieron registrar 5870 animales en 194 días entre noviembre de 2017 y mayo de 2019. Aves (77,13%) y mamíferos (22,84%) fueron las clases mejor representadas. Entre las aves, se destacan Coragyps atratus, Caracara plancus, Vultur gryphus y Milvago chimango, mientras que entre los mamíferos destaca Lycalopex griseus y las especies exóticas Sus scrofa y Canis lupus familiaris. Se observaron diferencias entre los ensambles faunísticos registrados en cada monitoreo en función del tiempo transcurrido desde la muerte de los animales y de su ubicación espacial.

This paper focuses in the morphometric analyses of Lama guanicoe remains recovered from the hunter-gatherer archaeological site Alero Deodoro Roca (ADR), located at Sierras Pampeanas Australes region (Córdoba Argentina), an area that has little information on the body-size variability of these artiodactyls. Because of the sparse osteometric data in the region, we focused on determining inter-intraspecific differentiation of wild camelids through corroborated osteometric techniques and multivariate statistical analyses of proximal phalanges. Our results showed a clear interspecific differentiation between modern vicuñas and archaeological specimens. We could also distinguish at least 3 guanaco size groups (small, medium and large) with the archaeological remains from the late Holocene (3000-3600 BP) of the site, presenting medium size characteristics. Finally this paper aims at establishing a first approach in the characterization of guanaco body size in the mountainous region of Córdoba.