Evidence for pedal arches or obligate bipedality in Hadar hominins

NewsBot · Sep 22, 2012

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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.
Mitchell PJ, Sarmiento EE, Meldrum DJ.
Homo. 2012 Sep 17.

Based on comparisons to non-statistically representative samples of humans and two great ape species (i.e. common chimpanzees Pan troglodytes and lowland gorillas Gorilla gorilla), Ward et al. (2011) concluded that a complete hominin fourth metatarsal (4th MT) from Hadar, AL 333-160, belonged to a committed terrestrial biped with fixed transverse and longitudinal pedal arches, which was no longer under selection favoring substantial arboreal behaviors. According to Ward et al., the Hadar 4th MT had (1) a torsion value indicating a transverse arch, (2) sagittal plane angles between the diaphyseal long axis and the planes of the articular surfaces indicating a longitudinal arch, and (3) a narrow mediolateral to dorsoplantar base ratio, an ectocuneiform facet, and tarsal articular surface contours all indicating a rigid foot without an ape-like mid-tarsal break. Comparisons of the Hadar 4th MT characters to those of statistically representative samples of humans, all five great ape species, baboons and proboscis monkeys show that none of the correlations Ward et al. make to localized foot function were supported by this analysis. The Hadar 4th MT characters are common to catarrhines that have a midtarsal break and lack fixed transverse or longitudinal arches. Further comparison of the AL 333-160 4th MT length, and base, midshaft and head circumferences to those of catarrhines with field collected body weights show that this bone is uniquely short with a large base. Its length suggests the AL 333-160 individual was a poor leaper with limited arboreal behaviors and lacked a longitudinal arch, i.e. its 4th MT long axis was usually held perpendicular to gravity. Its large base implies cuboid-4th MT joint mobility. A relatively short 4th MT head circumference indicates AL 333-160 had small proximal phalanges with a restricted range of mobility. Overall, AL 333-160 is most similar to the 4th MT of eastern gorillas, a slow moving quadruped that sacrifices arboreal behaviors for terrestrial ones. This study highlights evolutionary misconceptions underlying the practice of using localized anatomy and/or a single bony element to reconstruct overall locomotor behaviors and of summarizing great ape structure and behavior based on non-statistically representative samples of only a few living great ape species.
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Admin2 · Sep 22, 2012

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NewsBot · Jan 11, 2023

Arched footprints preserve the motions of fossil hominin feet
Kevin G Hatala et al
Source

The longitudinal arch of the human foot is viewed as a pivotal adaptation for bipedal walking and running. Fossil footprints from Laetoli, Tanzania, and Ileret, Kenya, are believed to provide direct evidence of longitudinally arched feet in hominins from the Pliocene and Pleistocene, respectively. We studied the dynamics of track formation using biplanar X-ray, three-dimensional animation and discrete element particle simulation. Here, we demonstrate that longitudinally arched footprints are false indicators of foot anatomy; instead they are generated through a specific pattern of foot kinematics that is characteristic of human walking. Analyses of fossil hominin tracks from Laetoli show only partial evidence of this walking style, with a similar heel strike but a different pattern of propulsion. The earliest known evidence for fully modern human-like bipedal kinematics comes from the early Pleistocene Ileret tracks, which were presumably made by members of the genus Homo. This result signals important differences in the foot kinematics recorded at Laetoli and Ileret and underscores an emerging picture of locomotor diversity within the hominin clade.
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NewsBot · Nov 1, 2023

Morphological and evolutionary insights into the keystone element of the human foot’s medial longitudinal arch
Rita Sorrentino, Kristian J. Carlson, Caley M. Orr, Annalisa Pietrobelli, Carla Figus, Shuyuan Li, Michele Conconi, Nicola Sancisi, Claudio Belvedere, Mingjie Zhu, Luca Fiorenza, Jean-Jacques Hublin, Tea Jashashvili, Mario Novak, Biren A. Patel, Thomas C. Prang, Scott A. Williams, Jaap P. P. Saers, Jay T. Stock, Timothy Ryan, Mark Myerson, Alberto Leardini, Jeremy DeSilva, Damiano Marchi, …Stefano Benazzi s
Communications Biology volume 6, Article number: 1061 (2023)

The evolution of the medial longitudinal arch (MLA) is one of the most impactful adaptations in the hominin foot that emerged with bipedalism. When and how it evolved in the human lineage is still unresolved. Complicating the issue, clinical definitions of flatfoot in living Homo sapiens have not reached a consensus. Here we digitally investigate the navicular morphology of H. sapiens (living, archaeological, and fossil), great apes, and fossil hominins and its correlation with the MLA. A distinctive navicular shape characterises living H. sapiens with adult acquired flexible flatfoot, while the congenital flexible flatfoot exhibits a ‘normal’ navicular shape. All H. sapiens groups differentiate from great apes independently from variations in the MLA, likely because of bipedalism. Most australopith, H. naledi, and H. floresiensis navicular shapes are closer to those of great apes, which is inconsistent with a human-like MLA and instead might suggest a certain degree of arboreality. Navicular shape of OH 8 and fossil H. sapiens falls within the normal living H. sapiens spectrum of variation of the MLA (including congenital flexible flatfoot and individuals with a well-developed MLA). At the same time, H. neanderthalensis seem to be characterised by a different expression of the MLA
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Evidence for pedal arches or obligate bipedality in Hadar hominins

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Evidence for pedal arches or obligate bipedality in Hadar hominins

NewsBot The Admin that posts the news.

Admin2 Administrator Staff Member

NewsBot The Admin that posts the news.

NewsBot The Admin that posts the news.

Barriers and enablers to implementing evidence into Podiatry practice.

Evidence based research on early walker footwear

Evidence of the use of soft footwear in the Gravettian cave of Cussac

Steps towards evidence-based foot-care for children

Logical fallacies in the running shoe debate: let the evidence guide prescription

Evidence for current recommendations concerning the management of foot health for people with chroni

Evidenced based practice

Share This Page

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