Ceramic technology of the Asurini do Xingu, Brazil: An ethnoarchaeological study of artifact variability

This article presents some of the results of ethnoarchaeological research on ceramic technology I have conducted among the Asurini do Xingu, an Amazonian indigenous population inhabiting a village in the margins of the Xingu River, Para, Brazil. Based on collected data, presented throughout the article, I discuss the reasons behind the formal, quantitative, spatial and relational variability of the Asurini ceramic vessels. This work will demonstrate that these distinct dimensions of variability are related to the potters` technological choices during the vessels` production process, the ceramic teaching-learning structure, and the type, frequency, method and context of use of the same vessels. I try to make clear the different practical and symbolic aspects that may influence the production, use, reuse, storage and discard processes of the vessels. Furthermore, I compare the Asurini context with other ethnographic contexts and try to distinguish regularities that may serve as interpretative references to the study of archaeological ceramic assemblages.

A trophic study of the sympatric Amazonian freshwater turtles Podocnemis unifilis and Podocnemis expansa (Testudines, Podocnemidae) using carbon and nitrogen stable isotope analyses

The Yellow-spotted River Turtle (Podocnemis unifilis Troschel, 1848) and the South American River Turtle (Podocnemis expansa (Schweigger, 1812)) are two turtles species that are widely distributed and have ecological, economic, and cultural importance in the Amazon basin. Although sympatric regarding most of their distribution, few studies have addressed the coexistence of these two species. To examine this, we analyzed the trophic level and the primary carbon source from the diets of both species in Baixo Araguaia, Tocantins, Brazil, using stable isotope analyses of carbon (delta C-13) and nitrogen (delta N-15). We also verified possible intraspecific variations (related to sex and body mass) in the trophic levels and primary carbon sources of their diets. Podocnemis unifilis had higher values of delta N-15 than P. expansa, averaging 7.59 parts per thousand and 5.06 parts per thousand, respectively, a difference which may indicate a possible trophic change owing to exploiting different food resources. No differences were found between the two species in relation to delta C-13 (mean values of -26.2 parts per thousand and -26.1 parts per thousand, respectively). The similarity between delta C-13 values suggests that the sources of their basal feeding are the same, consisting mainly of C-3 plants. There was no intraspecific variation in the values of delta C-13 and delta N-15.