The taphonomy and paleoenvironmental implications of the laetoli micromammals

Abstract

Recent fieldwork conducted between 1998 and 2005 significantly increased the sample of fossil rodent specimens from Laetoli, Tanzania, the type locality of Australopithecus afarensis and this allowed the identification of several new micromammal species. This chapter discusses the taphonomy and paleoenvironmental implications of the Laetoli rodents. The taphonomic analysis of the new material looks at element representation, breakage patterns and bone surface modification and finds evidence of predator activity and weathering. In terms of paleoenvironment, the Upper Laetolil Beds assemblage has a very low abundance of murine rodents, a predominantly arboreal taxon (Thallomys) alongside an arboreal sciurid (Paraxerus), and several fossorial and burrowing taxa, which we interpret to indicate the presence of acacia trees growing on loose, well-drained sediments in a semi-arid environment. The Upper Ndolanya Beds sample remains small, and the species preserved are the same as those found in the Upper Laetolil Beds, with the exception of Thryonomys. This provides tentative evidence for a more mesic local environment in Upper Ndolanya times relative to the Upper Laetolil Beds.