Craniometric variation within the pleistocene of Java: The Ngawi 1 cranium

The recently described cranium from Ngawi, East Java, is an important addition to the human fossil record. Several workers have placed Ngawi 1 into a grouping with the Ngandong and Sambungmacan specimens due to an overall metric and nonmetric similarity to those fossils. Multivariate comparisons of cranial shape have not been performed utilizing Ngawi, however, so it is unknown whether this specimen will fall within the current range of variation in those samples or if it will extend that range. Likewise, the inclusion of the Ngawi skull will allow a new test of the hypothesis that the African and Indonesian specimens currently allocated to Homo erectus exhibit a craniometric pattern that is significantly different from that seen in the Zhoukoudian crania. Mahalanobis distances will be used to examine the levels of variation present in a large sample representing the most complete African, Indonesian, and Chinese specimens of H. erectus. Statistical significance of the distances generated will be calculated using random expectation statistics. The results indicate that Ngawi shares strong shape similarities with the African and Indonesian specimens studied, and exhibits significant differences with the Zhoukoudian fossils. This supports earlier work by a number of scholars that found evidence of a unique craniometric pattern at that Chinese site. In addition, these tests indicate that cranial shape remained relatively invariant on Java for much of the Pleistocene. These findings, in conjunction with evidence for the appearance of unique nonmetric traits in the late-surviving Ngandong crania, suggest that the hominid populations of Java were relatively isolated for extended periods of time.