Bone differential survivorship and ontogenic development in guanaco (Lama guanicoe)

MARIELA GONZÁLEZ; MARÍA CLARA ALVAREZ; AGUSTINA MASSIGOGE; MARÍA A. GUTIÉRREZ; CRISTIAN KAUFMANN

París

Congreso; 11th International Conference of Archaeozoology; 2010

Muséum National d´Histoire Naturelle

This paper presents the results of a taphonomic research programconducted during the last four years. The main objective of this142 11th ICAZ International Conference. Paris, 23-28 August 2010program was to investigate differential survivorship in guanaco(Lama guanicoe) bones taking into account the ontogenetic developmentof this species and the densitometric characteristicsof its skeletal parts. In the first place, density analysis was carriedout from selected bones of modern individuals corresponding todifferent age classes. Secondly, two experimental designs wereconducted to explore the responses of bones from animals of differentages to weathering and fluvial transport. The first study isa long term experiment that intends to examine the deteriorationof skeletal elements from a newborn, a juvenile and an adult modernguanaco exposed at the same time to sub-aerial weatheringunder controlled conditions. The second experiment examinedthe hydrodynamic sorting of dry and wet skeletal elements from anewborn, a juvenile and an adult modern guanaco in an artificialflume under controlled current velocities (15 cm/s and 30 cm/s).The main result of this research program indicates that immaturebones have higher hydric transport potential and they weatheredat a faster rate. We proposed that this differential bone behavior ispartially related to their structural density as it evidenced by ourdensity analysis. These results alert on the age-related biases inzooarchaeological assemblages affected by taphonomic processes