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New Diagnostics for Bipedality: The hominin ilium displays landmarks of a modified growth trajectory

Zirkle, Dexter
http://rave.ohiolink.edu/etdc/view?acc_num=kent1647095837385269

Abstract Details

2022, PHD, Kent State University, College of Arts and Sciences / School of Biomedical Sciences.
The human ilium is significantly shorter and broader than are those of all other primates. In addition, it exhibits an anterior inferior iliac spine that emerges via a secondary center of ossification. It is also unique to hominins. Here we track the ontogeny of the ilium in human and subadult primate ossa coxae. We find that its ontogeny is exclusive among primates from anlagen to adulthood and that the fusion of the anterior inferior iliac spine is a capstone event of a unique growth process that repositions the anterior gluteal muscles for control of pelvic drop during upright walking. This novel growth process is therefore a hominin synapomorphy that can be used to assess the presence of bipedal locomotion in extinct taxa. We recently reported that a unique physis modulates broadening of the hominin ilium and shortening of its isthmus. We report here the discovery of a large, constant vascular foramen which lies close to the novel growth plate and serves as a central structure in the hominin ilium’s vascular network. No likely homologues appear in Old World Monkeys but are sometimes present in African great ape pelves. However, the human foramen (the Anterior Iliac Foramen) is significantly larger than the same individual’s nutrient foramen, and when corrected for body size, the human anterior iliac foramen is substantially larger than are those of apes. Those of Pan and Gorilla do not differ significantly from one another when so corrected, establishing that a small foramen is primitive and that its enlarged state is derived in hominins. This likely reflects amplification of the blood supply to the novel hominin physis during growth. Its presence in hominin fossil ilia can therefore provide evidence of iliac ontogenetic specialization for bipedality. The unique presence of this synapomorphy provides robust evidence that non-saltatory bipedality is a singular adaptation restricted to hominins, and that it has occurred only once in known primates.
C. Owen Lovejoy (Advisor)
Tobin Hieronymus (Committee Member)
Richard Meindl (Committee Member)
Mary Ann Raghanti (Committee Member)
155 p.
Biology; Biomechanics; Developmental Biology; Evolution and Development; Forensic Anthropology; Paleontology; Physical Anthropology; Radiology; Zoology
Australopithecus; Ardipithecus; physis; bipedality; hominin; hominid; pelvis; ilium; vascular; AIIS; anterior inferior iliac spine; acetabulum; foramen; AIF; anterior iliac foramen; apophysis; enthesis; growth plate; primate anatomy; human anatomy; human evolution; cartilage canal

Recommended Citations

Citations

  • Zirkle, D. (2022). New Diagnostics for Bipedality: The hominin ilium displays landmarks of a modified growth trajectory [Doctoral dissertation, Kent State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=kent1647095837385269

    APA Style (7th edition)

  • Zirkle, Dexter. New Diagnostics for Bipedality: The hominin ilium displays landmarks of a modified growth trajectory. 2022. Kent State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=kent1647095837385269.

    MLA Style (8th edition)

  • Zirkle, Dexter. "New Diagnostics for Bipedality: The hominin ilium displays landmarks of a modified growth trajectory." Doctoral dissertation, Kent State University, 2022. http://rave.ohiolink.edu/etdc/view?acc_num=kent1647095837385269

    Chicago Manual of Style (17th edition)

kent1647095837385269
247
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This open access ETD is published by Kent State University and OhioLINK.