Assessing Homo erectus sacral development using geometric morphometrics
Description
Anatomical shape differences between male and female pelvises are well established, but the timing of their development is less well understood. In hominin species, where growth rates may differ from humans, assessing developmental stage or sex from juvenile fossils is particularly difficult. One such fossil is the Homo erectus partial skeleton KNM-WT 15000. This juvenile skeleton was discovered in Kenya, dates to ~1.5 million years ago, and is thought to be male due to its large body size and height. Its exact age-at-death is debated due to conflicting skeletal maturity indicators that complicate the approximation of sex and age from this individual.
This project compared KNM-WT 15000 to non-adult human samples to estimate its developmental stage. Pelvic landmarks (34 total) were collected from human CT scans (N = 64) using 3D Slicer. Humans were divided evenly by sex and into three age groups (1–7 years, 8–11 years, ≥12 years). The same landmarks were collected from a surface scan of the reconstructed KNM-WT 15000 pelvis. Geometric morphometric analyses conducted in R showed that the H. erectus hipbone overlapped with all three human age groups, while the sacrum overlapped only with the youngest. These results suggest that sacral development differed in H. erectus, which would likely impact sacroiliac joint anatomy. Ongoing work will expand the comparative dataset and consider how to quantify sacroiliac differences between the two species.
Citation Information
Goldberg, Blaire; Gottlieb, Sydney; and VanSickle, Caroline, "Assessing Homo erectus sacral development using geometric morphometrics" (2026). Office of Research DMU Research Symposium. 100.
https://digitalcommons.dmu.edu/researchsymposium/2025rs/2025abstracts/100
Assessing Homo erectus sacral development using geometric morphometrics
Anatomical shape differences between male and female pelvises are well established, but the timing of their development is less well understood. In hominin species, where growth rates may differ from humans, assessing developmental stage or sex from juvenile fossils is particularly difficult. One such fossil is the Homo erectus partial skeleton KNM-WT 15000. This juvenile skeleton was discovered in Kenya, dates to ~1.5 million years ago, and is thought to be male due to its large body size and height. Its exact age-at-death is debated due to conflicting skeletal maturity indicators that complicate the approximation of sex and age from this individual.
This project compared KNM-WT 15000 to non-adult human samples to estimate its developmental stage. Pelvic landmarks (34 total) were collected from human CT scans (N = 64) using 3D Slicer. Humans were divided evenly by sex and into three age groups (1–7 years, 8–11 years, ≥12 years). The same landmarks were collected from a surface scan of the reconstructed KNM-WT 15000 pelvis. Geometric morphometric analyses conducted in R showed that the H. erectus hipbone overlapped with all three human age groups, while the sacrum overlapped only with the youngest. These results suggest that sacral development differed in H. erectus, which would likely impact sacroiliac joint anatomy. Ongoing work will expand the comparative dataset and consider how to quantify sacroiliac differences between the two species.
