Human variation in pelvic shape and the effects of climate and past population history

Lia Betti

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The human pelvis is often described as an evolutionary compromise (obstetrical dilemma) between the requirements of efficient bipedal locomotion and safe parturition of a highly encephalized neonate, that has led to a tight fit between the birth canal and the head and body of the foetus. Strong evolutionary constraints on the shape of the pelvis can be expected under this scenario. On the other hand, several studies have found a significant level of pelvic variation within and between human populations, a fact that seems to contradict such expectations. The advantages of a narrow pelvis for locomotion have recently been challenged, suggesting that the tight cephalo-pelvic fit might not stem from the hypothesized obstetrical dilemma. Moreover, the human pelvis appears to be under lower constraints and to have relatively higher evolvability than other closely related
primates. These recent findings substantially change the way in which we interpret variation in the human pelvis, and help make sense of the high diversity in pelvic shape observed within and among modern populations. A lower magnitude of covariance between functionally important regions ensured that a wide range of morphological variation was available within populations, enabling natural selection to generate pelvic variation between populations living in different environments. Neutral processes such as genetic drift and differential migration also contributed to shaping modern pelvic diversity during and after the expansion of humans into and across the various continents.

© 2017, Wiley Periodicals. The attached document (embargoed until 15/03/2018) is an author produced version of a paper published in in The Anatomical Record uploaded in accordance with the publisher’s self- archiving policy. The final published version (version of record) is available online at Some minor differences between this version and the final published version may remain. We suggest you refer to the final published version should you wish to cite from it.
Original languageEnglish
JournalAnatomical Record: Advances in Integrative Anatomy and Evolutionary Biology
Publication statusPublished - 15 Mar 2017


  • pelvis, climate, evolvability

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