Cranial Morphology and Variation of the Earliest Indonesian Hominids

Abstract

The Early Pleistocene deposits of Sangiran, Central Java, have yielded the oldest hominid fossils in Indonesia. This Sangiran assemblage is the oldest sizable hominid fossil collection so far known from Asia, and along with the African and Georgian arrays is the best comparative collection of Early Pleistocene Homo in the world. For this reason, the Sangiran hominid materials are important for understanding the dispersal and paleobiology of earlier members of our genus. However, due to ambiguous contextual documentation and the fragmentary nature of many of the existing fossils, our understanding of the taxonomic affinities and morphological variation of the earliest Indonesian hominids remains unclear. In this paper, we review recent chronostratigraphic data, and examine the Sangiran cranial remains. Contrary to previous arguments that the oldest Indonesian hominids are characterized by cranial robusticity, we propose that these hominids are actually highly variable, including both robust and gracile morphotypes. In overall cranial size and shape, and dentognathic morphology, the earliest Indonesian hominids appear to be comparable to c. 1.7 Ma early Homo erectus from East Africa. Evolutionary and taxonomic implications of these findings are discussed.