New insights into the palaeodiet and paleoenvironment of the camelids (Lama guanicoe) based on a palynological analysis of mid-Holocene coprolites from Cueva Milodon Norte 1, Pueyrredón Lake, Patagonia, Argentina

Abstract

The coprolites of archeological sites offer information about the paleobiology of organisms and paleoenvironment. Camelids were one of the main resources of hunter-gatherers inhabiting Patagonia and, therefore, the studies of the behavior of camelids from the Holocene are essential to increase the knowledge of human group dynamics. The aim of this study was to identify palaeodiet food items from the camelids in the Pueyrredón Lake area (Santa Cruz, Argentina) after the Hudson volcanic eruption (7800 cal. BP), and to contribute to the knowledge of the vegetation in the camelid home range. Camelid coprolites were collected from four archeological layers, which were dated between 5900 and 6260 cal. BP, in the site Cueva Milodón Norte 1 (47°00’S–72°15’W), in the area of the Pueyrredón Lake. Today, the vegetation of the area consists of a shrub-grass steppe near a deciduous forest of Nothofagus pumilio. According to a palynological analysis of coprolites, the dominant pollen types were Nothofagus, Asteraceae subf. Asteroideae, Cerastium and Poaceae, with concentrations of 24,000 to 111,000 grains/g. Among the putative diet items, pollen types with zoophilous dispersal were Asteraceae subf. Asteroideae, Cerastium and Acaena, while those with anemophilous dispersal were Poaceae and Nothofagus. The taxa currently growing in the Nothofagus forest include Onagraceae, Lathyrus and pteridophytes, such as Blechnum. The presence of these pollen types and spores suggests the use of the steppe and the forest by camelids in search of food.