Mammal bone weathering in a temperate coastal steppe (southern Patagonia, Argentina). A comparison among taxa.

CRUZ, I.; A. SEBASTIÁN MUÑOZ

Congreso; 12th Conference of the International Council for Archaeozoology (ICAZ; 2014

Bone weathering is the most important process to cause vertebrate remains degradation and destruction in Patagonia. Data recorded during an eight year time period on a temperate coastal steppe are presented here. We consider weathering features and relative rates among modern naturally deposited bone assemblages of three taxa, Guanaco (Lama guanicoe), South American sea lion (Otaria flavescens) and Andean fox (Lycalopex culpaeus) and apply a long term taphonomic naturalistic approach. Taphonomic processes on vertebrate bone remains are mediated by body size and morphology, and bone microstructure. The taxa considered have different body shapes and sizes. The Guanaco weights 80-100 kg, while sea lions 150-300kg ? female and male respectively- and Andean fox 8-10 kg. According to body size and anatomical differences it is expected to get different weathering patterns even under similar environmental conditions. Results show that Andean fox bones weather faster than those of bigger mammals, both marine and terrestrial, sea lion bones, instead, display a slower weathering rate than the terrestrial mammal bones, which is in agreement with previous expectations. Furthermore, guanaco and fox long bones weather faster than flat and compact bones of the same species while sea lion bones do not display this kind of differences. Bone microstructure and shape could explain the former pattern, while sea lion denser long bones with no medullar cavity the latter one.