A reevaluation of the paleoenvironmental reconstructions associated with Homo erectus from Java, Indonesia, based on the functional morphology of fossil bovid astragali

The Middle Pleistocene sites of Trinil and Kedung Brubus, Java, Indonesia have provided extensive faunal remains that are classified as part of a larger biostratigraphic framework. Paleoenvironmental reconstructions, associated with early hominids on Java, have been constructed based on the composition and perceived shared habitat preference of fossil and modern animal taxa. Research of the African members of the family Bovidae has shown that a more effective way of examining past environments is through the study of morphological traits that are characteristic of functional adaptations to different environmental conditions. This research represents the successful extension of this method by testing several parametric and nonparametric statistical models for habitat prediction based on bovid astragali from Southeast Asia. The results of the fossil analysis indicate the paleoenvironment at the Trinil site (ca. 1 Ma) was dominated by densely vegetated river valleys and upland forests, broken by open grasslands. These grasslands probably expanded during the period associated with the Kedung Brubus locality, approximately 0.8 Ma. This environmental change, coupled with the immigration of new species, was important to the appearance and future evolutionary success of Homo erectus during the Middle Pleistocene.