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Parallel lumbar and pelvic morphology in atelines and early hominids: clues to the earliest hominid adaptations to upright walking?
Author(s) -
Machnicki Allison L,
HaileSelassie Yohannes,
Spurlock Linda,
Mendes Sérgio L,
Strier Karen B,
McCollum Melanie A,
Lovejoy C. Owen
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.756.11
Subject(s) - bipedalism , anatomy , lumbar lordosis , prehensile tail , lumbar , lordosis , australopithecus , sacrum , biology , medicine , radiography , surgery
Lumbar lordosis is a critical element of human bipedality, because it obviates the need for African ape style bent‐hip‐bent‐knee (BHBK) gait. Apes have eliminated lumbar mobility by trapping the most caudal lumbars between dorsally extended ilia. The earliest known hominids show the opposite state—emancipation of the most caudal lumbar by reduction in iliac height and expansion of sacral alar breadth. Ateline monkeys have flexible prehensile tails, which, when used simultaneously with their forelimbs for support, induce substantial lordosis. To determine if similar skeletal and ligamentous morphology underlies lumbar lordosis in atelines and hominids, we examined (dissection, MRI, X‐ray) the pelves and lumbar columns across anthropoids. We find substantial parallels between hominids and atelines including reduced iliac height and position of the sacrum relative to the ilium and pubis. These results indicate that lowering iliac height is a likely first step in directly evolving bipedality without any reliance on a BHBK gait. Grant Funding Source : None