Pelvic Morphology in Homo erectus and Early Homo

The evolution of the hominin pelvis is generally seen as involving two broad stages: the establishment of bipedal pelvic morphology by the mid-Pliocene (or earlier), followed by architectural changes necessary to enlarge the birth canal in response to increased encephalization in Pleistocene members of the genus Homo. Pelvic and proximal femoral morphology in early Homo (namely H. erectus) has been seen as transitional between these stages, reflecting structural changes necessitated by greater body size (and perhaps moderate increases in brain size) overlain upon a basically primitive pelvic architecture. Here we review the history of thought on the evolution of the pelvis in early Homo, as well as recent fossil discoveries that have improved our understanding of diversity in pelvic morphology in early Homo and late australopiths. These discoveries (1) suggest that the "femoropelvic complex" characteristic of H. erectus emerged after the divergence of various lineages of early Homo (that is, it is not plesiomorphic for the genus) and (2) raise questions about the role that evolutionary change in brain size in the genus Homo played in the emergence of derived features seen in the pelvis of modern humans. Anat Rec, 300:964-977, 2017. © 2017 Wiley Periodicals, Inc.