This study applies both phenetic and evolutionary methods in a reappraisal of African Homo erectus fossils. Both measurements and discrete morphological observations are made on cranial, mandibular and dental remains from all of the important African localities. Fossils from Dmanisi and localities in China and the Far East are treated in comparisons. The aims of this research are to reassess the population biology of African Homo erectus, sort the fossils into paleo-demes, determine the nature of morphological patterning, test the use of paleo-demes as Operational Taxonomic Units (OTUs) in intra-taxic analysis, and to reconstruct possible evolutionary relationships of the African sample with Asian Homo erectus and other members of the genus Homo.

Results of univariate, bivariate and multivariate analyses provide a firmer basis for recognizing regional differences and long-term trends within the Homo erectus hypodigm. For instance, the multivariate results confirms close affinities of East Turkana hominins to those at Dmanisi, while the Daka and OH 9 crania are more similar to the Far Eastern paleo-demes, especially the Indonesian stock. This analysis confirms the close affinities between Trinil-Sangiran and Chinese groups on the one hand, and Ngandong-Ngawi-Sambungmacan groups on the other. These findings indicate that the paleo-demeas-OTUs approach yields conclusions consistent with results from analyses based on individual specimens. Also, evidence of early modernity observed in Africa, especially as exemplified by the vertical and expanded parietals in the Daka, Buia, and Illeret (KNM-ER 42700) crania, offers a possible explanation for the differentiation into later hominins. The KNM-BK 8518 mandible shows the greatest thickness at the symphysis in the mandibular series, and its corpus thickness at M2 differentiates it from Northwest African Middle Pleistocene hominin jaws. The characterization of its lower premolar dimensions either expands the ranges for Homo erectus and early Homo or may help differentiate the Baringo specimen from the two groups.

This work directly contributes to our current knowledge on evolutionary relationships concerning Homo erectus and other hominins. These results suggest that in situ evolution within the African Homo erectus group contributed to the origins and dispersal of other groups, especially those from the Far East.