Multivariate analysis as a taphonomic tool in the study of quaternary mammal associations from Northeastern Brazil

Abstract

In this work we carried out a multivariate analysis of taxonomic representativeness of mammal fossil bones in the Quaternary deposits from Northeastern Brazil, normally found in tanks (natural depressions in the crystalline basement), and caves originated from karstic deposits. The method employed was the cluster analysis. Taphocoenoses also composed by mammal bones from South Brazil and northermost Argentine were included in the analysis for comparative purposes. The results show that the northeastern Brazilian deposits formed a main group, distinct from the southern ones by the presence of endemic taxa of the Brazilian Intertropical Zone. Yet the analysis show that two subgroups are included within the Northeast Brazil taphocoenoses, one that includes the cave karstic deposits, characterized by great taxonomic diversity and large, medium and small sized mammals, and the other including all materials coming from tanks and ravines, where large mammals dominate. Taphonomic biases seem to be the best explanation to the distinct mammal distribution and selection in the tanks and ravines, when compared with those from the caves. However, the possibility that those distinct depositions could also represent a time-averaging process could not be discarded to the cave deposits.

Key words: multivariate analysis, cluster analysis, taphonomy, mammals, Quaternary, NE Brazil.