A multidisciplinary investigation into whether Andean caravans reached the southern lowlands of the Paraná-Plata basin during pre-Columbian times

The expansion of llama caravans and the dispersal of domesticated camelids to extra-Andean regions is one of the key topics in South American archaeology. One of the main indicators of both processes is the presence of domesticated camelids in the archaeological record, particularly the llama (Lama glama). Based primarily on historical sources subject to interpretation, it has been suggested that llama caravans may have reached the southeast of South America during Pre-Columbian times, particularly to the northern Pampean region and the Paraná River valley. While the archaeological assemblages in these two areas include camelid bones that have thus far been identified as guanaco (Lama guanicoe), the possibility of misidentification due to the osteometric similarity between the latter and L. glama could mask the presence of domestic camelids in the record, undermining evidence of this potential major expansion of Andean caravans and domestic camelids. To clarify this issue, we applied a multidisciplinary approach combining archaeological, isotopic, and paleogenomic analyses to determine the taxonomic status of camelids recovered from archaeological sites in northern Pampean region and the valley of the Paraná River. Our findings demonstrate that all the individuals analyzed correspond to guanacos, whose survival extended into early historical times. Additionally, the archaeological record from both areas contemporaneous with the maximum pre-Columbian expansion of the Andean caravans, provides no evidence of direct trade with the Andean world.