The AL 333-160 fourth metatarsal from Hadar compared to that of humans, great apes, baboons and proboscis monkeys: Non-conclusive evidence for pedal arches or obligate bipedality in Hadar hominins

Mitchell, Paul; Sarmiento, Esteban E.; Meldrum, D. Jeffrey

doi:10.1016/j.jchb.2012.08.001

Cited by 11 publications

(7 citation statements)

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“…The discovery of a complete fourth metatarsal (A.L. 333-160) provided support for the hypothesis that A. afarensis had both longitudinal and transverse arches (Ward et al, 2011; but see Harmon, 2013 andMitchell et al, 2012 for alternative views), and a recent analysis of rearfoot angular relationships also found support for this hypothesis (Prang, 2015b). Thus, there are several lines of evidence based on foot morphology suggestive of a longitudinal arch in A. afarensis, which are congruent with the structural and functional inferences derived from the Laetoli footprints (Day and Wickens, 1980;White, 1980;White and Suwa, 1987;Bennett et al, 2009;Raichlen et al, 2010;Crompton et al, 2012;Bennett et al, 2016).…”

Section: Introductionmentioning

confidence: 95%

Reevaluating the functional implications of Australopithecus afarensis navicular morphology

Prang

2016

Journal of Human Evolution

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The longitudinal arch is a unique characteristic of the human foot, yet the timing and pattern of its evolution remain controversial, in part due to the disagreement among researchers over which skeletal traits are the best indicators of its presence or absence. The small size of the human navicular tuberosity has previously been linked to the presence of a longitudinal arch, implying that the large tuberosity of early hominins such as Australopithecus afarensis reflects a flat foot. However, this hypothesis is at odds with other evidence of pedal form and function, such as metatarsal, tarsal, and footprint morphology, which show that a longitudinal arch was probably present in A. afarensis. This study reevaluates the morphometric affinities of the A. afarensis naviculars among other Plio-Pleistocene fossil hominins and anthropoid primates (N = 170). Multivariate cluster analyses show that all fossil hominin naviculars, including those attributed to A. afarensis, are most similar to modern humans. A measure of navicular tuberosity size quantified as the ratio of the tuberosity volume to the surface area of the talar facet shows that Ateles has the largest navicular tuberosity among the anthropoid sample and that there is no difference between highly arboreal and terrestrial taxa in this metric (e.g., Hylobates and Gorilla beringei). Instead, a relatively large navicular tuberosity may reflect the development of leg musculature associated with ankle plantarflexion. The functional inferences derived from the morphology of the A. afarensis naviculars are consistent with the morphology of the Laetoli footprints.

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Section: Introductionmentioning

confidence: 95%

Reevaluating the functional implications of Australopithecus afarensis navicular morphology

Prang

2016

Journal of Human Evolution

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“…However, Australopithecus afarensis (3.8–2.9 Ma) is now generally agreed to have had a longitudinal arch, as demonstrated most clearly in the morphology of a complete fourth metatarsal 2 8 (but see ref. 12 for an alternative view) and the attribution of the Laetoli fossil footprints (3.7 Ma) to this taxon 13 14 .…”

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confidence: 99%

Rearfoot posture of Australopithecus sediba and the evolution of the hominin longitudinal arch

Prang

2015

Sci Rep

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The longitudinal arch is one of the hallmarks of the human foot but its evolutionary history remains controversial due to the fragmentary nature of the fossil record. In modern humans, the presence of a longitudinal arch is reflected in the angular relationships among the major surfaces of the human talus and calcaneus complex, which is also known as the rearfoot. A complete talus and calcaneus of Australopithecus sediba provide the opportunity to evaluate rearfoot posture in an early hominin for the first time. Here I show that A. sediba is indistinguishable from extant African apes in the angular configuration of its rearfoot, which strongly suggests that it lacked a longitudinal arch. Inferences made from isolated fossils support the hypothesis that Australopithecus afarensis possessed an arched foot. However, tali attributed to temporally younger taxa like Australopithecus africanus and Homo floresiensis are more similar to those of A. sediba. The inferred absence of a longitudinal arch in A. sediba would be biomechanically consistent with prior suggestions of increased midtarsal mobility in this taxon. The morphological patterns in talus and calcaneus angular relationships among fossil hominins suggest that there was diversity in traits associated with the longitudinal arch in the Plio-Pleistocene.

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“…In addition to fossil scarcity and lack of preservation, longstanding disagreements about methods of research and interpretations surrounding early fossil foot bones exist within the paleoanthropological community (Stern, ; Harcourt‐Smith and Aiello, ; D'Aout and Aerts, ; DeSilva and Throckmorton, ; Griffin and Richmond, ; Griffin et al, ; Venkataraman et al, ). Fossilized footprints of early bipeds also exist in the record, but similar disagreements have revolved around interpretation of the form and function of the hominin feet that made the earliest of footprints known to date, the 3.6 million year‐old trackways at Laetoli, Tanzania (Day and Wickens, ; White and Suwa, ; Tuttle et al, ; Bennett et al, ; DeSilva and Throckmorton, ; Raichlen et al, ; Crompton et al, ; Mitchell et al, ).…”

Section: Triceps Surae and Plantar Aponeurosismentioning

confidence: 99%

Understanding the evolution of the windlass mechanism of the human foot from comparative anatomy: Insights, obstacles, and future directions

Griffin

Miller

Schmitt

et al. 2014

American J Phys Anthropol

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Humans stand alone from other primates in that we propel our bodies forward on a relatively stiff and arched foot and do so by employing an anatomical arrangement of bones and ligaments in the foot that can operate like a "windlass." This is a significant evolutionary innovation, but it is currently unknown when during hominin evolution this mechanism developed and within what genera or species it originated. The presence of recently discovered fossils along with novel research in the past two decades have improved our understanding of foot mechanics in humans and other apes, making it possible to consider this question more fully. Here we review the main elements thought to be involved in the production of an effective, modern human-like windlass mechanism. These elements are the triceps surae, plantar aponeurosis, medial longitudinal arch, and metatarsophalangeal joints. We discuss what is presently known about the evolution of these features and the challenges associated with identifying each of these specific components and/or their function in living and extinct primates for the purpose of predicting the presence of the windlass mechanism in our ancestors. In some cases we recommend alternative pathways for inferring foot mechanics and for testing the hypothesis that the windlass mechanism evolved to increase the speed and energetic efficiency of bipedal gait in hominins.

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The AL 333-160 fourth metatarsal from Hadar compared to that of humans, great apes, baboons and proboscis monkeys: Non-conclusive evidence for pedal arches or obligate bipedality in Hadar hominins

Cited by 11 publications

References 72 publications

Reevaluating the functional implications of Australopithecus afarensis navicular morphology

Reevaluating the functional implications of Australopithecus afarensis navicular morphology

Rearfoot posture of Australopithecus sediba and the evolution of the hominin longitudinal arch

Understanding the evolution of the windlass mechanism of the human foot from comparative anatomy: Insights, obstacles, and future directions

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