Large Mammal Evidence for the Paleoenvironment of the Upper Laetolil and Upper Ndolanya Beds of Laetoli, Tanzania.

There has been much debate on the environment of Pliocene Laetoli. These disagreements reflect the complexity of the paleoenvironment and the difficulties in reconciling contradictory evidence. In this paper, the community structure of the large mammal fauna at Laetoli is compared to that of modern faunal communities and the relative abundances of bovid tribes are examined. The results of these analyses are interpreted within the context of other lines of evidence, including those based on rodents, gastropods, phytoliths, stable isotopes and mesowear. The balance of evidence suggests that the ecology of the Upper Laetolil Beds was a mosaic of grassland-shrubland-open woodland habitats with extensive woody vegetation in the form of shrubs, thickets, and bush. There was also a significant presence of dense woodland and possibly riverine forest habitats. The results also indicate that the ecological conditions in the Upper Laetolil Beds became progressively drier and less wooded through time. There is no clear consensus as to the paleoenvironment of the Upper Ndolanya Beds. While there is evidence to suggest that it was drier and more open than the Upper Laetolil Beds, there is contrary evidence indicating that it was at least as humid and wooded as the Upper Laetolil Beds. [ABSTRACT FROM AUTHOR]