Tarsometatarsus, eggshells, and the species level identification of large-sized flightless birds from Boyo Paso 2 (Sierras of Córdoba, Argentina)

Abstract

The article presents the taxonomic study carried out on the Rheidae (Palaeognathae: Ratitae) faunal remains recovered in the open-air archaeological site Boyo Paso 2 dated at approximately 1500–750 years BP (Sierras of Córdoba, Argentina). The study is focused on an adult proximal tarsometatarsus, a juvenile distal tarsometatarsus and 453 eggshell remains. The specimens were identified to its most specific level exploring and describing the diagnostic keys to species/genera level identification in modern reference collections. Two Rheidae species were identified: Rhea cf. R. americana and Rhea cf. R. pennata. However, most specimens were assigned to Rhea sp., including the tarsometatarsus remains. Taxonomic assignments indicate that even with the adoption of plant cultivation approximately 1.500 years BP, a broad spectrum foraging base played a key role for late prehispanic daily subsistence, increasing now the number of identified species added to the subsistence as the one not previously considered R. pennata. Its identification also suggests that the late prehispanic environment presented a higher biodiversity than at present, being the modern landscape a nonaccurate analogue of past conditions. It is concluded that achieving taxonomic identification to the most specific possible level becomes the fundamental pillars to assess the taxonomic diversity of human past subsistence as well as characterize the paleoenvironment, which mixed cultivation and foraging people interacted.