Pelvic shape variation across development: Human growth compared with Australopithecus sediba
Description
The human pelvis remodels during growth, with males and females growing similarly until puberty, when they differentiate. The timeline of the development of pelvic dimorphism in human ancestors remains understudied. Here, we considered a 1.98 Ma South African fossil hemipelvis of Australopithecus sediba; while our study individual was an adult, it shared similarities with a less complete juvenile male of the same species.
This study investigated how the pelvic shape changes with age and sex in humans, with the goal of using human developmental anatomy to assess pelvic shape in A. sediba with respect to age and sex.
CT scans of 78 humans (ages 1–16 years) were landmarked in 3D Slicer along with a surface scan of the reconstructed hemipelvis of MH2. A geometric morphometric analysis was performed in R on 27 landmarks. The resulting principal components analysis visualized shape variation across species, sexes, and developmental stages.
Preliminary results illustrated that human pelvic shape variation was primarily driven by age, not sex. Surprisingly, the A. sediba fossil overlapped with the younger humans, despite being an adult. These results may reflect MH2’s more human-like sacrum combined with a markedly different ilium, but further investigation is needed.
These findings contributed to our understanding of how pelvic dimorphism develops in humans and provided a framework for evaluating fossil pelves. Our results have implications for future research in pediatrics, forensic anthropology, and paleoanthropology.
Citation Information
Gottlieb, Sydney; Goldberg, Blaire; and VanSickle, Caroline, "Pelvic shape variation across development: Human growth compared with Australopithecus sediba" (2026). Office of Research DMU Research Symposium. 105.
https://digitalcommons.dmu.edu/researchsymposium/2025rs/2025abstracts/105
Pelvic shape variation across development: Human growth compared with Australopithecus sediba
The human pelvis remodels during growth, with males and females growing similarly until puberty, when they differentiate. The timeline of the development of pelvic dimorphism in human ancestors remains understudied. Here, we considered a 1.98 Ma South African fossil hemipelvis of Australopithecus sediba; while our study individual was an adult, it shared similarities with a less complete juvenile male of the same species.
This study investigated how the pelvic shape changes with age and sex in humans, with the goal of using human developmental anatomy to assess pelvic shape in A. sediba with respect to age and sex.
CT scans of 78 humans (ages 1–16 years) were landmarked in 3D Slicer along with a surface scan of the reconstructed hemipelvis of MH2. A geometric morphometric analysis was performed in R on 27 landmarks. The resulting principal components analysis visualized shape variation across species, sexes, and developmental stages.
Preliminary results illustrated that human pelvic shape variation was primarily driven by age, not sex. Surprisingly, the A. sediba fossil overlapped with the younger humans, despite being an adult. These results may reflect MH2’s more human-like sacrum combined with a markedly different ilium, but further investigation is needed.
These findings contributed to our understanding of how pelvic dimorphism develops in humans and provided a framework for evaluating fossil pelves. Our results have implications for future research in pediatrics, forensic anthropology, and paleoanthropology.
