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Druelle F, Ghislieri M, Molina-Vila P, Rimbaud B, Agostini V, Berillon G. A comparative study of muscle activity and synergies during walking in baboons and humans. J Hum Evol 2024; 189:103513. [PMID: 38401300 DOI: 10.1016/j.jhevol.2024.103513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2023] [Revised: 02/15/2024] [Accepted: 02/16/2024] [Indexed: 02/26/2024]
Abstract
Bipedal locomotion was a major functional change during hominin evolution, yet, our understanding of this gradual and complex process remains strongly debated. Based on fossil discoveries, it is possible to address functional hypotheses related to bipedal anatomy, however, motor control remains intangible with this approach. Using comparative models which occasionally walk bipedally has proved to be relevant to shed light on the evolutionary transition toward habitual bipedalism. Here, we explored the organization of the neuromuscular control using surface electromyography (sEMG) for six extrinsic muscles in two baboon individuals when they walk quadrupedally and bipedally on the ground. We compared their muscular coordination to five human subjects walking bipedally. We extracted muscle synergies from the sEMG envelopes using the non-negative matrix factorization algorithm which allows decomposing the sEMG data in the linear combination of two non-negative matrixes (muscle weight vectors and activation coefficients). We calculated different parameters to estimate the complexity of the sEMG signals, the duration of the activation of the synergies, and the generalizability of the muscle synergy model across species and walking conditions. We found that the motor control strategy is less complex in baboons when they walk bipedally, with an increased muscular activity and muscle coactivation. When comparing the baboon bipedal and quadrupedal pattern of walking to human bipedalism, we observed that the baboon bipedal pattern of walking is closer to human bipedalism for both baboons, although substantial differences remain. Overall, our findings show that the muscle activity of a non-adapted biped effectively fulfills the basic mechanical requirements (propulsion and balance) for walking bipedally, but substantial refinements are possible to optimize the efficiency of bipedal locomotion. In the evolutionary context of an expanding reliance on bipedal behaviors, even minor morphological alterations, reducing muscle coactivation, could have faced strong selection pressure, ultimately driving bipedal evolution in hominins.
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Affiliation(s)
- François Druelle
- Histoire Naturelle de l'Homme Préhistorique, UMR 7194, CNRS-MNHN-UPVD, Musée de l'Homme, 17 place du Trocadéro, 75116 Paris, France; Primatology Station of the CNRS, UAR 846, 2230 route des quatre tours, 13790 Rousset, France; Functional Morphology Laboratory, University of Antwerp, Campus Drie Eiken (Building D), Universiteitsplein 1, 2610 Antwerp, Belgium.
| | - Marco Ghislieri
- Department of Electronics and Telecommunications, Politecnico di Torino, Corso Duca degli Abruzzi, 24, 10129 Turin, Italy; PoliTo(BIO)Med Lab, Politecnico di Torino, Corso Duca degli Abruzzi, 24, 10129 Turin, Italy
| | - Pablo Molina-Vila
- Primatology Station of the CNRS, UAR 846, 2230 route des quatre tours, 13790 Rousset, France
| | - Brigitte Rimbaud
- Primatology Station of the CNRS, UAR 846, 2230 route des quatre tours, 13790 Rousset, France
| | - Valentina Agostini
- Department of Electronics and Telecommunications, Politecnico di Torino, Corso Duca degli Abruzzi, 24, 10129 Turin, Italy; PoliTo(BIO)Med Lab, Politecnico di Torino, Corso Duca degli Abruzzi, 24, 10129 Turin, Italy
| | - Gilles Berillon
- Histoire Naturelle de l'Homme Préhistorique, UMR 7194, CNRS-MNHN-UPVD, Musée de l'Homme, 17 place du Trocadéro, 75116 Paris, France; Primatology Station of the CNRS, UAR 846, 2230 route des quatre tours, 13790 Rousset, France
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Nalley TK, Scott JE, McGechie F, Grider-Potter N. Comparative ontogeny of functional aspects of human cervical vertebrae. AMERICAN JOURNAL OF BIOLOGICAL ANTHROPOLOGY 2024; 183:e24788. [PMID: 37283367 DOI: 10.1002/ajpa.24788] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 05/15/2023] [Accepted: 05/24/2023] [Indexed: 06/08/2023]
Abstract
OBJECTIVES Differences between adult humans and great apes in cervical vertebral morphology are well documented, but the ontogeny of this variation is still largely unexplored. This study examines patterns of growth in functionally relevant features of C1, C2, C4, and C6 in extant humans and apes to understand the development of their disparate morphologies. MATERIALS AND METHODS Linear and angular measurements were taken from 530 cervical vertebrae representing 146 individual humans, chimpanzees, gorillas, and orangutans. Specimens were divided into three age-categories based on dental eruption: juvenile, adolescent, and adult. Inter- and intraspecific comparisons were evaluated using resampling methods. RESULTS Of the eighteen variables examined here, seven distinguish humans from apes at the adult stage. Human-ape differences in features related to atlantoaxial joint function tend to be established by the juvenile stage, whereas differences in features related to the nuchal musculature and movement of the subaxial elements do not fully emerge until adolescence or later. The orientation of the odontoid process-often cited as a feature that distinguishes humans from apes-is similar in adult humans and adult chimpanzees, but the developmental patterns are distinct, with human adultlike morphology being achieved much earlier. DISCUSSION The biomechanical consequences of the variation observed here is poorly understood. Whether the differences in growth patterns represent functional links to cranial development or postural changes, or both, requires additional investigation. Determining when humanlike ontogenetic patterns evolved in hominins may provide insight into the functional basis driving the morphological divergence between extant humans and apes.
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Affiliation(s)
- Thierra K Nalley
- Medical Anatomical Sciences Department, College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona, California, USA
| | - Jeremiah E Scott
- Medical Anatomical Sciences Department, College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona, California, USA
| | - Faye McGechie
- Department of Basic Medical Sciences, University of Arizona College of Medicine-Phoenix, Phoenix, Arizona, USA
| | - Neysa Grider-Potter
- Department of Cell Systems and Anatomy, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
- Southwest National Primate Research Center, Texas Biomedical Research Institute, San Antonio, Texas, USA
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O'Neill MC, Nagano A, Umberger BR. A three-dimensional musculoskeletal model of the pelvis and lower limb of Australopithecus afarensis. AMERICAN JOURNAL OF BIOLOGICAL ANTHROPOLOGY 2024; 183:e24845. [PMID: 37671481 DOI: 10.1002/ajpa.24845] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 07/08/2023] [Accepted: 08/17/2023] [Indexed: 09/07/2023]
Abstract
OBJECTIVES Musculoskeletal modeling is a powerful approach for studying the biomechanics and energetics of locomotion. Australopithecus (A.) afarensis is among the best represented fossil hominins and provides critical information about the evolution of musculoskeletal design and locomotion in the hominin lineage. Here, we develop and evaluate a three-dimensional (3-D) musculoskeletal model of the pelvis and lower limb of A. afarensis for predicting muscle-tendon moment arms and moment-generating capacities across lower limb joint positions encompassing a range of locomotor behaviors. MATERIALS AND METHODS A 3-D musculoskeletal model of an adult A. afarensis pelvis and lower limb was developed based primarily on the A.L. 288-1 partial skeleton. The model includes geometric representations of bones, joints and 35 muscle-tendon units represented using 43 Hill-type muscle models. Two muscle parameter datasets were created from human and chimpanzee sources. 3-D muscle-tendon moment arms and isometric joint moments were predicted over a wide range of joint positions. RESULTS Predicted muscle-tendon moment arms generally agreed with skeletal metrics, and corresponded with human and chimpanzee models. Human and chimpanzee-based muscle parameterizations were similar, with some differences in maximum isometric force-producing capabilities. The model is amenable to size scaling from A.L. 288-1 to the larger KSD-VP-1/1, which subsumes a wide range of size variation in A. afarensis. DISCUSSION This model represents an important tool for studying the integrated function of the neuromusculoskeletal systems in A. afarensis. It is similar to current human and chimpanzee models in musculoskeletal detail, and will permit direct, comparative 3-D simulation studies.
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Affiliation(s)
- Matthew C O'Neill
- Department of Anatomy, Midwestern University, Glendale, Arizona, USA
| | - Akinori Nagano
- Faculty of Sport and Health Science, Ritsumeikan University, Kusatsu, Shiga, Japan
| | - Brian R Umberger
- School of Kinesiology, University of Michigan, Ann Arbor, Michigan, USA
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Wiseman AL, Charles JP, Hutchinson JR. Static versus dynamic muscle modelling in extinct species: a biomechanical case study of the Australopithecus afarensis pelvis and lower extremity. PeerJ 2024; 12:e16821. [PMID: 38313026 PMCID: PMC10838096 DOI: 10.7717/peerj.16821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 01/02/2024] [Indexed: 02/06/2024] Open
Abstract
The force a muscle generates is dependent on muscle structure, in which fibre length, pennation angle and tendon slack length all influence force production. Muscles are not preserved in the fossil record and these parameters must be estimated when constructing a musculoskeletal model. Here, we test the capability of digitally reconstructed muscles of the Australopithecus afarensis model (specimen AL 288-1) to maintain an upright, single-support limb posture. Our aim was to ascertain the influence that different architectural estimation methods have on muscle specialisation and on the subsequent inferences that can be extrapolated about limb function. Parameters were estimated for 36 muscles in the pelvis and lower limb and seven different musculoskeletal models of AL 288-1 were produced. These parameters represented either a 'static' Hill-type muscle model (n = 4 variants) which only incorporated force, or instead a 'dynamic' Hill-type muscle model with an elastic tendon and fibres that could vary force-length-velocity properties (n = 3 variants). Each muscle's fibre length, pennation angle, tendon slack length and maximal isometric force were calculated based upon different input variables. Static (inverse) simulations were computed in which the vertical and mediolateral ground reaction forces (GRF) were incrementally increased until limb collapse (simulation failure). All AL 288-1 variants produced somewhat similar simulated muscle activation patterns, but the maximum vertical GRF that could be exerted on a single limb was not consistent between models. Three of the four static-muscle models were unable to support >1.8 times body weight and produced models that under-performed. The dynamic-muscle models were stronger. Comparative results with a human model imply that similar muscle group activations between species are needed to sustain single-limb support at maximally applied GRFs in terms of the simplified static simulations (e.g., same walking pose) used here. This approach demonstrated the range of outputs that can be generated for a model of an extinct individual. Despite mostly comparable outputs, the models diverged mostly in terms of strength.
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Affiliation(s)
- Ashleigh L.A. Wiseman
- McDonald Institute for Archaeological Research, University of Cambridge, Cambridge, United Kingdom
| | - James P. Charles
- Evolutionary Morphology and Biomechanics Lab, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, United Kingdom
| | - John R. Hutchinson
- Structure and Motion Laboratory, Department of Comparative Biomedical Sciences, Royal Veterinary College, Hatfield, United Kingdom
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Wiseman ALA. Three-dimensional volumetric muscle reconstruction of the Australopithecus afarensis pelvis and limb, with estimations of limb leverage. ROYAL SOCIETY OPEN SCIENCE 2023; 10:230356. [PMID: 37325588 PMCID: PMC10265029 DOI: 10.1098/rsos.230356] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 05/24/2023] [Indexed: 06/17/2023]
Abstract
To understand how an extinct species may have moved, we first need to reconstruct the missing soft tissues of the skeleton, which rarely preserve, with an understanding of segmental volume and muscular composition within the body. The Australopithecus afarensis specimen AL 288-1 is one of the most complete hominin skeletons. Despite 40+ years of research, the frequency and efficiency of bipedal movement in this specimen is still debated. Here, 36 muscles of the pelvis and lower limb were reconstructed using three-dimensional polygonal modelling, guided by imaging scan data and muscle scarring. Reconstructed muscle masses and configurations guided musculoskeletal modelling of the lower limb in comparison with a modern human. Results show that the moment arms of both species were comparable, hinting towards similar limb functionality. Moving forward, the polygonal muscle modelling approach has demonstrated promise for reconstructing the soft tissues of hominins and providing information on muscle configuration and space filling. This method demonstrates that volumetric reconstructions are required to know where space must be occupied by muscles and thus where lines of action might not be feasible due to interference with another muscle. This approach is effective for reconstructing muscle volumes in extinct hominins for which musculature is unknown.
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Alemseged Z. Reappraising the palaeobiology of Australopithecus. Nature 2023; 617:45-54. [PMID: 37138108 DOI: 10.1038/s41586-023-05957-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 03/14/2023] [Indexed: 05/05/2023]
Abstract
The naming of Australopithecus africanus in 1925, based on the Taung Child, heralded a new era in human evolutionary studies and turned the attention of the then Eurasian-centric palaeoanthropologists to Africa, albeit with reluctance. Almost one hundred years later, Africa is recognized as the cradle of humanity, where the entire evolutionary history of our lineage prior to two million years ago took place-after the Homo-Pan split. This Review examines data from diverse sources and offers a revised depiction of the genus and characterizes its role in human evolution. For a long time, our knowledge of Australopithecus came from both A. africanus and Australopithecus afarensis, and the members of this genus were portrayed as bipedal creatures that did not use stone tools, with a largely chimpanzee-like cranium, a prognathic face and a brain slightly larger than that of chimpanzees. Subsequent field and laboratory discoveries, however, have altered this portrayal, showing that Australopithecus species were habitual bipeds but also practised arboreality; that they occasionally used stone tools to supplement their diet with animal resources; and that their infants probably depended on adults to a greater extent than what is seen in apes. The genus gave rise to several taxa, including Homo, but its direct ancestor remains elusive. In sum, Australopithecus had a pivotal bridging role in our evolutionary history owing to its morphological, behavioural and temporal placement between the earliest archaic putative hominins and later hominins-including the genus Homo.
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Stamos PA, Alemseged Z. Hominin locomotion and evolution in the Late Miocene to Late Pliocene. J Hum Evol 2023; 178:103332. [PMID: 36947894 DOI: 10.1016/j.jhevol.2023.103332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 01/26/2023] [Accepted: 01/27/2023] [Indexed: 03/24/2023]
Abstract
In this review, we present on the evolution of the locomotor adaptation of hominins in the Late Miocene to Late Pliocene, with emphasis on some of the prominent advances and debates that have occurred over the past fifty years. We start with the challenging issue of defining hominin locomotor grades that are currently used liberally and offer our own working definitions of facultative, habitual, and obligate bipedalism. We then discuss the nature of the Pan-Homo last common ancestor and characterize the locomotor adaptation of Sahelanthropus, Orrorin, and Ardipithecus-often referred to as facultative bipeds-and examine the debates on the extent of bipedality and arboreality in these taxa. Moreover, the question of Middle Pliocene hominin locomotor diversity is addressed based on information derived from the 'Little Foot' specimen from Sterkfontein, footprints from Laetoli, and the Burtele Foot in Ethiopia. Our review suggests that the most convincing evidence for locomotor diversity comes from Burtele, whereas the evidence from Sterkfontein and Laetoli is unconvincing and equivocal, respectively. Finally, we address the decades old issue of the significance of arboreality in the otherwise habitual biped, Australopithecus, with emphasis on Australopithecus afarensis and its implications for the paleobiology of these creatures. We conclude that many of the apelike features encountered, mostly in the upper part of the Australopithecus skeleton, were retained for their significance in climbing. Approaches that have investigated character plasticity and those exploring internal bone structure have shown that the shoulder and limbs in Au. afarensis and Australopithecus africanus were involved in arboreal activities that are thought to be key for feeding, nesting, and predator avoidance. We conclude that many of the so-called retained ape-like features persisted due to stabilizing selection, that early hominins engaged in a considerable amount of arboreality even after Australopithecus had become a habitual biped, and arboreality only ceased to be an important component of hominin locomotor behavior after the emergence of Homo erectus.
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Affiliation(s)
- Peter A Stamos
- Department of Organismal Biology & Anatomy, The University of Chicago, Anatomy Bldg 201, 1027 E 57th Street, Chicago, IL 60637, USA
| | - Zeresenay Alemseged
- Department of Organismal Biology & Anatomy, The University of Chicago, Anatomy Bldg 201, 1027 E 57th Street, Chicago, IL 60637, USA.
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Figus C, Stephens NB, Sorrentino R, Bortolini E, Arrighi S, Higgins OA, Lugli F, Marciani G, Oxilia G, Romandini M, Silvestrini S, Baruffaldi F, Belcastro MG, Bernardini F, Festa A, Hajdu T, Mateovics‐László O, Pap I, Szeniczey T, Tuniz C, Ryan TM, Benazzi S. Morphologies in-between: The impact of the first steps on the human talus. Anat Rec (Hoboken) 2023; 306:124-142. [PMID: 35656925 PMCID: PMC10083965 DOI: 10.1002/ar.25010] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 05/15/2022] [Accepted: 05/16/2022] [Indexed: 01/29/2023]
Abstract
OBJECTIVE The development of bipedalism is a very complex activity that contributes to shaping the anatomy of the foot. The talus, which starts ossifying in utero, may account for the developing stages from the late gestational phase onwards. Here, we explore the early development of the talus in both its internal and external morphology to broaden the knowledge of the anatomical changes that occur during early development. MATERIALS AND METHODS The sample consists of high-resolution microCT scans of 28 modern juvenile tali (from 36 prenatal weeks to 2 years), from a broad chronological range from the Late Roman period to the 20th century. We applied geometric morphometric and whole-bone trabecular analysis to investigate the early talar morphological changes. RESULTS In the youngest group (<6 postnatal months), the immature external shell is accompanied by an isotropic internal structure, with thin and densely packed trabeculae. After the initial attempts of locomotion, bone volume fraction decreases, while anisotropy and trabecular thickness increase. These internal changes correspond to the maturation of the external shell, which is now more defined and shows the development of the articular surfaces. DISCUSSION The internal and external morphology of the human talus reflects the diverse load on the foot during the initial phases of the bipedal locomotion, with the youngest group potentially reflecting the lack of readiness of the human talus to bear forces and perform bipedal walking. These results highlight the link between mechanical loading and bone development in the human talus during the acquisition of bipedalism, providing new insight into the early phases of talar development.
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Affiliation(s)
- Carla Figus
- Department of Cultural HeritageUniversity of BolognaRavennaItaly
| | - Nicholas B. Stephens
- Department of AnthropologyPennsylvania State UniversityState CollegePennsylvaniaUSA
| | - Rita Sorrentino
- Department of Cultural HeritageUniversity of BolognaRavennaItaly
- Department of Biological, Geological and Environmental Sciences – BigeaUniversity of BolognaBolognaItaly
| | - Eugenio Bortolini
- Department of Cultural HeritageUniversity of BolognaRavennaItaly
- Human Ecology and Archaeology (HUMANE)IMF, CSI0CBarcelonaSpain
| | - Simona Arrighi
- Department of Cultural HeritageUniversity of BolognaRavennaItaly
| | - Owen A. Higgins
- Department of Cultural HeritageUniversity of BolognaRavennaItaly
| | - Federico Lugli
- Department of Cultural HeritageUniversity of BolognaRavennaItaly
| | - Giulia Marciani
- Department of Cultural HeritageUniversity of BolognaRavennaItaly
- Research Unit Prehistory and Anthropology, Department of Physical Sciences, Earth and EnvironmentUniversity of SienaSienaItaly
| | - Gregorio Oxilia
- Department of Cultural HeritageUniversity of BolognaRavennaItaly
| | - Matteo Romandini
- Department of Cultural HeritageUniversity of BolognaRavennaItaly
| | - Sara Silvestrini
- Department of Cultural HeritageUniversity of BolognaRavennaItaly
| | - Fabio Baruffaldi
- Laboratory of Medical TechnologyIRCCS Istituto Ortopedico RizzoliBolognaItaly
| | - Maria Giovanna Belcastro
- Department of Biological, Geological and Environmental Sciences – BigeaUniversity of BolognaBolognaItaly
| | - Federico Bernardini
- Department of Humanistic StudiesUniversità Ca'FoscariVeneziaItaly
- Multidisciplinary LaboratoryAbdus Salam International Centre for Theoretical PhysicsTriesteItaly
| | - Anna Festa
- Laboratory of Medical TechnologyIRCCS Istituto Ortopedico RizzoliBolognaItaly
| | - Tamás Hajdu
- Department of Biological Anthropology, Institute of Biology, Faculty of ScienceEötvös Loránd UniversityBudapestHungary
| | | | - Ildiko Pap
- Department of Biological Anthropology, Institute of Biology, Faculty of ScienceEötvös Loránd UniversityBudapestHungary
- Department of Biological Anthropology, Institute of Biology, Faculty of Science and InformaticsSzeged UniversitySzegedHungary
- Department of AnthropologyHungarian Natural History MuseumBudapestHungary
| | - Tamás Szeniczey
- Department of Biological Anthropology, Institute of Biology, Faculty of ScienceEötvös Loránd UniversityBudapestHungary
| | - Claudio Tuniz
- Multidisciplinary LaboratoryAbdus Salam International Centre for Theoretical PhysicsTriesteItaly
- Centre for Archaeological ScienceUniversity of WollongongWollongongNew South WalesAustralia
| | - Timothy M. Ryan
- Department of AnthropologyPennsylvania State UniversityState CollegePennsylvaniaUSA
| | - Stefano Benazzi
- Department of Cultural HeritageUniversity of BolognaRavennaItaly
- Department of Human EvolutionMax Planck Institute for Evolutionary AnthropologyLeipzigGermany
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Hatala KG, Gatesy SM, Falkingham PL. Arched footprints preserve the motions of fossil hominin feet. Nat Ecol Evol 2023; 7:32-41. [PMID: 36604550 DOI: 10.1038/s41559-022-01929-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 10/07/2022] [Indexed: 01/07/2023]
Abstract
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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Affiliation(s)
- Kevin G Hatala
- Department of Biology, Chatham University, Pittsburgh, PA, USA.
| | - Stephen M Gatesy
- Department of Ecology, Evolution, and Organismal Biology, Brown University, Providence, RI, USA
| | - Peter L Falkingham
- School of Biological and Environmental Sciences, Liverpool John Moores University, Liverpool, UK
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Grine FE, Mongle CS, Fleagle JG, Hammond AS. The taxonomic attribution of African hominin postcrania from the Miocene through the Pleistocene: Associations and assumptions. J Hum Evol 2022; 173:103255. [PMID: 36375243 DOI: 10.1016/j.jhevol.2022.103255] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 08/21/2022] [Accepted: 08/22/2022] [Indexed: 11/06/2022]
Abstract
Postcranial bones may provide valuable information about fossil taxa relating to their locomotor habits, manipulative abilities and body sizes. Distinctive features of the postcranial skeleton are sometimes noted in species diagnoses. Although numerous isolated postcranial fossils have become accepted by many workers as belonging to a particular species, it is worthwhile revisiting the evidence for each attribution before including them in comparative samples in relation to the descriptions of new fossils, functional analyses in relation to particular taxa, or in evolutionary contexts. Although some workers eschew the taxonomic attribution of postcranial fossils as being less important (or interesting) than interpreting their functional morphology, it is impossible to consider the evolution of functional anatomy in a taxonomic and phylogenetic vacuum. There are 21 widely recognized hominin taxa that have been described from sites in Africa dated from the Late Miocene to the Middle Pleistocene; postcranial elements have been attributed to 17 of these. The bones that have been thus assigned range from many parts of a skeleton to isolated elements. However, the extent to which postcranial material can be reliably attributed to a specific taxon varies considerably from site to site and species to species, and is often the subject of considerable debate. Here, we review the postcranial remains attributed to African hominin taxa from the Late Miocene to the Middle and Late Pleistocene and place these assignations into categories of reliability. The catalog of attributions presented here may serve as a guide for making taxonomic decisions in the future.
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Affiliation(s)
- Frederick E Grine
- Department of Anthropology, Stony Brook University, Stony Brook, NY 11794-4364, USA; Department of Anatomical Sciences, Stony Brook University, Stony Brook, NY 11794-4364, USA.
| | - Carrie S Mongle
- Department of Anthropology, Stony Brook University, Stony Brook, NY 11794-4364, USA; Division of Anthropology, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024-5192, USA; Turkana Basin Institute, Stony Brook University, Stony Brook, NY 11794-4364, USA
| | - John G Fleagle
- Department of Anatomical Sciences, Stony Brook University, Stony Brook, NY 11794-4364, USA
| | - Ashley S Hammond
- Division of Anthropology, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024-5192, USA; New York Consortium of Evolutionary Primatology (NYCEP), New York, NY 10024, USA
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11
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Druelle F, Özçelebi J, Marchal F, Berillon G. Development of bipedal walking in olive baboons, Papio anubis: A kinematic analysis. AMERICAN JOURNAL OF BIOLOGICAL ANTHROPOLOGY 2022; 177:719-734. [PMID: 36787778 DOI: 10.1002/ajpa.24454] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 10/24/2021] [Accepted: 11/07/2021] [Indexed: 11/09/2022]
Abstract
OBJECTIVE Although extant nonhuman primates are not habitual bipeds, they are able to walk bipedally from an early age. In humans, children improve their walking skills through developmental processes and learning experience. In nonhuman primates, infants do not routinely experience bipedalism and their musculoskeletal system gradually specializes for other locomotor modes. The aim of this study is to explore the development of occasional bipedal walking in olive baboon and to test whether the postural adjustments change with age. MATERIALS AND METHODS We collected kinematics and spatiotemporal parameters of bipedal gait in an ontogenetic sample of 24 baboons. Data were collected at the primatology station of the CNRS (France) and a total of 47 bipedal strides were extracted for the present analysis. RESULTS Adults and adolescents walk bipedally in the same way, and the average kinematic pattern is similar across the age-classes. Infants walk bipedally with longer duty factor, they present larger movement amplitude of the thigh and the amplitude of the knee joint decreases with speed. In contrast, older baboons increase the amplitude of the knee and ankle joints with speed. DISCUSSION In a non-adapted biped, the postural adjustments of bipedal walking vary with age. In infant baboons, the balance requirements are likely to be higher and these are solved by adopting a "blocking strategy". In older baboons, the postural adjustments are focused on the lower limb and the movements increase with speed. These results may echo, in some respects, the developmental sequence of the intersegmental coordination described in the ontogeny of human locomotion.
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Affiliation(s)
- François Druelle
- UMR 7194 (Histoire Naturelle de l'Homme Préhistorique), CNRS-Muséum National d'Histoire Naturelle-UPVD, Paris, France.,Functional Morphology Laboratory, University of Antwerp, Antwerp, Belgium.,UAR 846, Primatology Station-Celphedia, CNRS, Rousset, France
| | - Jonathan Özçelebi
- UMR 7194 (Histoire Naturelle de l'Homme Préhistorique), CNRS-Muséum National d'Histoire Naturelle-UPVD, Paris, France.,UMR 7268 (Anthropologie Bio-Culturelle, Droit, Ethique et Santé), CNRS-Faculté de Médecine, Marseille, France
| | - François Marchal
- UMR 7268 (Anthropologie Bio-Culturelle, Droit, Ethique et Santé), CNRS-Faculté de Médecine, Marseille, France
| | - Gilles Berillon
- UMR 7194 (Histoire Naturelle de l'Homme Préhistorique), CNRS-Muséum National d'Histoire Naturelle-UPVD, Paris, France.,UAR 846, Primatology Station-Celphedia, CNRS, Rousset, France
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12
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Deckers K, Tsegai ZJ, Skinner MM, Zeininger A, Kivell TL. Ontogenetic changes to metacarpal trabecular bone structure in mountain and western lowland gorillas. J Anat 2022; 241:82-100. [PMID: 35122239 PMCID: PMC9178373 DOI: 10.1111/joa.13630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 01/05/2022] [Accepted: 01/06/2022] [Indexed: 11/28/2022] Open
Abstract
The trabecular bone morphology of adult extant primates has been shown to reflect mechanical loading related to locomotion. However, ontogenetic studies of humans and other mammals suggest an adaptive lag between trabecular bone response and current mechanical loading patterns that could result in adult trabecular bone morphology reflecting juvenile behaviours. This study investigates ontogenetic changes in the trabecular bone structure of the third metacarpal of mountain gorillas (Gorilla beringei beringei; n = 26) and western lowland gorillas (Gorilla gorilla gorilla; n = 26) and its relationship to expected changes in locomotor loading patterns. Results show that trabecular bone reflects predicted mechanical loading throughout ontogeny. Bone volume fraction, trabecular thickness and trabecular number are low at birth and increase with age, although degree of anisotropy remains relatively stable throughout ontogeny. A high concentration of bone volume fraction can be observed in the distopalmar region of the third metacarpal epiphysis in early ontogeny, consistent with the high frequency of climbing, suspensory and other grasping behaviours in young gorillas. High trabecular bone concentration increases dorsally in the epiphysis during the juvenile period as terrestrial knuckle-walking becomes the primary form of locomotion. However, fusion of the epiphysis does not take place until 10-11 years of age, and overall trabecular structure does not fully reflect the adult pattern until 12 years of age, indicating a lag between adult-like behaviours and adult-like trabecular morphology. We found minimal differences in trabecular ontogeny between mountain and western lowland gorillas, despite presumed variation in the frequencies of arboreal locomotor behaviours. Altogether, ontogenetic changes in Gorilla metacarpal trabecular structure reflect overall genus-level changes in locomotor behaviours throughout development, but with some ontogenetic lag that should be considered when drawing functional conclusions from bone structure in extant or fossil adolescent specimens.
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Affiliation(s)
- Kim Deckers
- Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, Kent, UK
| | - Zewdi J Tsegai
- Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, Kent, UK.,Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Matthew M Skinner
- Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, Kent, UK.,Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Angel Zeininger
- Department of Evolutionary Anthropology, Duke University, Durham, North Carolina, USA
| | - Tracy L Kivell
- Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, Kent, UK.,Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
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13
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Johnson RT, O'Neill MC, Umberger BR. The effects of posture on the three-dimensional gait mechanics of human walking in comparison to bipedal chimpanzees. J Exp Biol 2022; 225:274182. [DOI: 10.1242/jeb.243272] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 01/24/2022] [Indexed: 11/20/2022]
Abstract
Humans walk with an upright posture on extended limbs during stance and with a double-peaked vertical ground reaction force. Our closest living relatives, chimpanzees, are facultative bipeds that walk with a crouched posture on flexed, abducted hind limbs and with a single-peaked vertical ground reaction force. Differences in human and bipedal chimpanzee three-dimensional kinematics have been well quantified, yet it is unclear what the independent effects of using a crouched posture are on three-dimensional gait mechanics for humans, and how they compare with chimpanzees. Understanding the relationships between posture and gait mechanics, with known differences in morphology between species, can help researchers better interpret the effects of trait evolution on bipedal walking. We quantified pelvis and lower limb three-dimensional kinematics and ground reaction forces as humans adopted a series of upright and crouched postures and compared them with data from bipedal chimpanzee walking. Human crouched posture gait mechanics were more similar to bipedal chimpanzee gait than normal human walking, especially in sagittal plane hip and knee angles. However, there were persistent differences between species, as humans walked with less transverse plane pelvis rotation, less hip abduction, and greater peak horizontal ground reaction force in late stance than chimpanzees. Our results suggest that human crouched posture walking reproduces only a small subset of the characteristics of three-dimensional kinematics and ground reaction forces of chimpanzee walking, with the remaining differences likely due in large part to the distinct musculoskeletal morphologies of humans and chimpanzees.
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Affiliation(s)
- Russell T. Johnson
- Department of Kinesiology, University of Massachusetts Amherst, Amherst MA, USA
- Division of Biokinesiology and Physical Therapy, University of Southern California, Los Angeles CA, USA
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14
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McNutt EJ, Hatala KG, Miller C, Adams J, Casana J, Deane AS, Dominy NJ, Fabian K, Fannin LD, Gaughan S, Gill SV, Gurtu J, Gustafson E, Hill AC, Johnson C, Kallindo S, Kilham B, Kilham P, Kim E, Liutkus-Pierce C, Maley B, Prabhat A, Reader J, Rubin S, Thompson NE, Thornburg R, Williams-Hatala EM, Zimmer B, Musiba CM, DeSilva JM. Footprint evidence of early hominin locomotor diversity at Laetoli, Tanzania. Nature 2021; 600:468-471. [PMID: 34853470 PMCID: PMC8674131 DOI: 10.1038/s41586-021-04187-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 10/22/2021] [Indexed: 11/08/2022]
Abstract
Bipedal trackways discovered in 1978 at Laetoli site G, Tanzania and dated to 3.66 million years ago are widely accepted as the oldest unequivocal evidence of obligate bipedalism in the human lineage1-3. Another trackway discovered two years earlier at nearby site A was partially excavated and attributed to a hominin, but curious affinities with bears (ursids) marginalized its importance to the paleoanthropological community, and the location of these footprints fell into obscurity3-5. In 2019, we located, excavated and cleaned the site A trackway, producing a digital archive using 3D photogrammetry and laser scanning. Here we compare the footprints at this site with those of American black bears, chimpanzees and humans, and we show that they resemble those of hominins more than ursids. In fact, the narrow step width corroborates the original interpretation of a small, cross-stepping bipedal hominin. However, the inferred foot proportions, gait parameters and 3D morphologies of footprints at site A are readily distinguished from those at site G, indicating that a minimum of two hominin taxa with different feet and gaits coexisted at Laetoli.
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Affiliation(s)
- Ellison J McNutt
- Department of Biomedical Sciences, Ohio University Heritage College of Medicine, Athens, OH, USA.
- Department of Integrative Anatomical Sciences, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA.
| | - Kevin G Hatala
- Department of Biology, Chatham University, Pittsburgh, PA, USA
| | - Catherine Miller
- Ecology, Evolution, Environment and Society Graduate Program, Dartmouth College, Hanover, NH, USA
- Department of Anthropology, Dartmouth College, Hanover, NH, USA
| | - James Adams
- Dartmouth Library, Dartmout College, Hanover, NH, USA
- Information, Technology, and Consulting, Dartmouth College, Hanover, NH, USA
| | - Jesse Casana
- Ecology, Evolution, Environment and Society Graduate Program, Dartmouth College, Hanover, NH, USA
- Department of Anthropology, Dartmouth College, Hanover, NH, USA
| | - Andrew S Deane
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Nathaniel J Dominy
- Ecology, Evolution, Environment and Society Graduate Program, Dartmouth College, Hanover, NH, USA
- Department of Anthropology, Dartmouth College, Hanover, NH, USA
| | - Kallisti Fabian
- Department of Cultural Heritage, Ngorongoro Conservation Area Authority, Arusha, Tanzania
| | - Luke D Fannin
- Ecology, Evolution, Environment and Society Graduate Program, Dartmouth College, Hanover, NH, USA
- Department of Anthropology, Dartmouth College, Hanover, NH, USA
| | - Stephen Gaughan
- Information, Technology, and Consulting, Dartmouth College, Hanover, NH, USA
| | - Simone V Gill
- Department of Occupational Therapy, Boston University, Boston, MA, USA
| | - Josephat Gurtu
- Department of Cultural Heritage, Ngorongoro Conservation Area Authority, Arusha, Tanzania
| | - Ellie Gustafson
- Department of Anthropology, University of Colorado, Denver, CO, USA
| | - Austin C Hill
- Department of Anthropology, Dartmouth College, Hanover, NH, USA
- Department of Anthropology, University of Pennsylvania, Philadelphia, PA, USA
| | - Camille Johnson
- Department of Anthropology, Dartmouth College, Hanover, NH, USA
| | - Said Kallindo
- Department of Cultural Heritage, Ngorongoro Conservation Area Authority, Arusha, Tanzania
| | | | | | - Elizabeth Kim
- Department of Integrative Anatomical Sciences, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Cynthia Liutkus-Pierce
- Department of Geological and Environmental Sciences, Appalachian State University, Boone, NC, USA
| | - Blaine Maley
- Department of Anatomy, Idaho College of Osteopathic Medicine, Meridian, ID, USA
| | - Anjali Prabhat
- Department of Anthropology, Dartmouth College, Hanover, NH, USA
| | - John Reader
- Department of Anthropology, University College London, London, UK
| | - Shirley Rubin
- Department of Anthropology, Napa Valley College, Napa, CA, USA
| | - Nathan E Thompson
- Department of Anatomy, NYIT College of Osteopathic Medicine, Old Westbury, NY, USA
| | - Rebeca Thornburg
- Department of Anthropology, University of Colorado, Denver, CO, USA
| | | | - Brian Zimmer
- Department of Geological and Environmental Sciences, Appalachian State University, Boone, NC, USA
| | - Charles M Musiba
- Department of Anthropology, University of Colorado, Denver, CO, USA
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa
- Instituto Superior Politécnico de Tecnologia e Ciências, Luanda Angola, Angola
| | - Jeremy M DeSilva
- Ecology, Evolution, Environment and Society Graduate Program, Dartmouth College, Hanover, NH, USA
- Department of Anthropology, Dartmouth College, Hanover, NH, USA
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa
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15
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Hatala KG, Gatesy SM, Falkingham PL. Integration of biplanar X-ray, three-dimensional animation and particle simulation reveals details of human 'track ontogeny'. Interface Focus 2021; 11:20200075. [PMID: 34938432 DOI: 10.1098/rsfs.2020.0075] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/16/2021] [Indexed: 11/12/2022] Open
Abstract
The emergence of bipedalism had profound effects on human evolutionary history, but the evolution of locomotor patterns within the hominin clade remains poorly understood. Fossil tracks record in vivo behaviours of extinct hominins, and they offer great potential to reveal locomotor patterns at various times and places across the human fossil record. However, there is no consensus on how to interpret anatomical or biomechanical patterns from tracks due to limited knowledge of the complex foot-substrate interactions through which they are produced. Here, we implement engineering-based methods to understand human track formation with the ultimate goal of unlocking invaluable information on hominin locomotion from fossil tracks. We first developed biplanar X-ray and three-dimensional animation techniques that permit visualization of subsurface foot motion as tracks are produced, and that allow for direct comparisons of foot kinematics to final track morphology. We then applied the discrete element method to accurately simulate the process of human track formation, allowing for direct study of human track ontogeny. This window lets us observe how specific anatomical and/or kinematic variables shape human track morphology, and it offers a new avenue for robust hypothesis testing in order to infer patterns of foot anatomy and motion from fossil hominin tracks.
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Affiliation(s)
- Kevin G Hatala
- Department of Biology, Chatham University, Pittsburgh, PA 15232, USA
| | - Stephen M Gatesy
- Department of Ecology and Evolutionary Biology, Brown University, Providence, RI 02912, USA
| | - Peter L Falkingham
- School of Biological and Environmental Sciences, Liverpool John Moores University, Liverpool L3 3AF, UK
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16
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Asghar A, Naaz S. The transverse arch in the human feet: A narrative review of its evolution, anatomy, biomechanics and clinical implications. Morphologie 2021; 106:225-234. [PMID: 34419345 DOI: 10.1016/j.morpho.2021.07.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 07/25/2021] [Accepted: 07/26/2021] [Indexed: 10/20/2022]
Abstract
The dominant characteristics of the human foot are its shock-absorbing capability during walking or gait cycle and its adaptation to uneven surfaces. On the stance phase of the gait, the foot has to be flexible at first for shock absorption and adapt to the terrain; whereas, during the propulsive phase, it has to be dynamically rigid to function as a lever. Foot flexibility and rigidity are mainly controlled at the subtalar and midtarsal joints by tendons and ligaments. The subtalar joint is part of the longitudinal arch, but the midtarsal joint along with the tarsometatarsal joint are components of the transverse arch. However, the existence and functional role of transverse arch in human was challenged by some authors. But recent studies have revealed that the transverse arch has a predominant role in midfoot stiffness (Venkadeshan et al., 2020, & Holowoka et al., 2017). This midfoot stiffness allows the human foot to store elastic energy at the time of heel strike, which is utilized during the push-off mechanism for propulsion, thus making bipedalism more energy-efficient. Moreover, the transverse arch allows the longitudinal arch to be flexible like a lever and, at the same time, makes the arch of the foot rigid to behave like a stiff spring lever. Understanding the role of the transverse arch is obligatory to study the biomechanics of foot injuries and Charcot or diabetic foot. Studies on diabetic foot have shown that the modulation of transverse arch biomechanics and off-loading modalities would improve outcomes in the form of wound-healing and prevention of re-ulceration.
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Affiliation(s)
- A Asghar
- Department of Anatomy, All India Institute of Medical Sciences, Patna, India.
| | - S Naaz
- Department of Anaesthesiology, All India Institute of Medical Sciences, Patna, India
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17
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Prabhat AM, Miller CK, Prang TC, Spear J, Williams SA, DeSilva JM. Homoplasy in the evolution of modern human-like joint proportions in Australopithecus afarensis. eLife 2021; 10:65897. [PMID: 33978569 PMCID: PMC8116054 DOI: 10.7554/elife.65897] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 04/19/2021] [Indexed: 11/22/2022] Open
Abstract
The evolution of bipedalism and reduced reliance on arboreality in hominins resulted in larger lower limb joints relative to the joints of the upper limb. The pattern and timing of this transition, however, remains unresolved. Here, we find the limb joint proportions of Australopithecus afarensis, Homo erectus, and Homo naledi to resemble those of modern humans, whereas those of A. africanus, Australopithecus sediba, Paranthropus robustus, Paranthropus boisei, Homo habilis, and Homo floresiensis are more ape-like. The homology of limb joint proportions in A. afarensis and modern humans can only be explained by a series of evolutionary reversals irrespective of differing phylogenetic hypotheses. Thus, the independent evolution of modern human-like limb joint proportions in A. afarensis is a more parsimonious explanation. Overall, these results support an emerging perspective in hominin paleobiology that A. afarensis was the most terrestrially adapted australopith despite the importance of arboreality throughout much of early hominin evolution.
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Affiliation(s)
| | - Catherine K Miller
- Anthropology, Dartmouth College, Hanover, United States.,Ecology, Evolution, Ecosystems, and Society, Dartmouth College, Hanover, United States
| | - Thomas Cody Prang
- Department of Anthropology, Texas A&M University, College Station, United States
| | - Jeffrey Spear
- Center for the Study of Human Origins, Department of Anthropology, New York University, New York, United States.,New York Consortium in Evolutionary Primatology, New York, United States
| | - Scott A Williams
- Center for the Study of Human Origins, Department of Anthropology, New York University, New York, United States.,New York Consortium in Evolutionary Primatology, New York, United States
| | - Jeremy M DeSilva
- Anthropology, Dartmouth College, Hanover, United States.,Ecology, Evolution, Ecosystems, and Society, Dartmouth College, Hanover, United States
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18
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DeSilva JM, McNutt E, Zipfel B, Ward CV, Kimbel WH. Associated Australopithecusafarensis second and third metatarsals (A.L. 333-133) from Hadar, Ethiopia. J Hum Evol 2020; 146:102848. [PMID: 32717476 DOI: 10.1016/j.jhevol.2020.102848] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 06/05/2020] [Accepted: 06/05/2020] [Indexed: 10/23/2022]
Affiliation(s)
- Jeremy M DeSilva
- Department of Anthropology, Dartmouth College, Hanover, NH, 03755, USA.
| | - Ellison McNutt
- Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA
| | - Bernhard Zipfel
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa
| | - Carol V Ward
- Integrative Anatomy Program, Department of Pathology and Anatomical Sciences, School of Medicine, University of Missouri, Columbia, MO, 65212, USA
| | - William H Kimbel
- Institute of Human Origins and School of Human Evolution and Social Change, Arizona State University, Tempe, AZ, 85287, USA
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19
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Morphometric analysis of the hominin talus: Evolutionary and functional implications. J Hum Evol 2020; 142:102747. [PMID: 32240884 DOI: 10.1016/j.jhevol.2020.102747] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2019] [Revised: 01/07/2020] [Accepted: 01/21/2020] [Indexed: 11/21/2022]
Abstract
The adoption of bipedalism is a key benchmark in human evolution that has impacted talar morphology. Here, we investigate talar morphological variability in extinct and extant hominins using a 3D geometric morphometric approach. The evolutionary timing and appearance of modern human-like features and their contributions to bipedal locomotion were evaluated on the talus as a whole, each articular facet separately, and multiple combinations of facets. Distinctive suites of features are consistently present in all fossil hominins, despite the presence of substantial interspecific variation, suggesting a potential connection of these suites to bipedal gait. A modern human-like condition evolved in navicular and lateral malleolar facets early in the hominin lineage compared with other facets, which demonstrate more complex morphological variation within Homininae. Interestingly, navicular facet morphology of Australopithecus afarensis is derived in the direction of Homo, whereas more recent hominin species such as Australopithecus africanus and Australopithecus sediba retain more primitive states in this facet. Combining the navicular facet with the trochlea and the posterior calcaneal facet as a functional suite, however, distinguishes Australopithecus from Homo in that the medial longitudinal arch had not fully developed in the former. Our results suggest that a more everted foot and stiffer medial midtarsal region are adaptations that coincide with the emergence of bipedalism, whereas a high medial longitudinal arch emerges later in time, within Homo. This study provides novel insights into the emergence of talar morphological traits linked to bipedalism and its transition from a facultative to an obligate condition.
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20
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McNutt EJ, DeSilva JM. Evidence for an elongated Achilles tendon in Australopithecus. Anat Rec (Hoboken) 2020; 303:2382-2391. [PMID: 32134211 DOI: 10.1002/ar.24387] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 01/04/2020] [Accepted: 01/07/2020] [Indexed: 11/11/2022]
Abstract
Modern humans have the longest Achilles tendon (AT) of all the living primates. It has been proposed that this anatomy increases locomotor efficiency and that its elongation may have played a crucial role in the origin and early evolution of the genus Homo. Unfortunately, determining the length of the AT in extinct hominins has been difficult as tendons do not fossilize. Several methods have been proposed for estimating the length of the AT from calcaneal morphology, but the results have been inconclusive. This study tested the relationship between the area of the superior calcaneal facet and AT length in extant primates. The superior facet is instructive because it anchors the retrocalcaneal bursa, a soft tissue structure which helps to reduce friction between the AT and the calcaneus. Calcanei from 145 extant anthropoid primates from 12 genera were photographed in posterior view and the relative superior facet size quantified. AT lengths were obtained from published sources. The relative area of the superior facet is predictive of AT length in primates (R2 = 0.83; p < .001) and differs significantly between the great apes and humans (p < 0.001). When applied to fossil Australopithecus calcanei, our results suggest that australopiths possessed a longer, more human-like, AT than previously thought. These findings have important implications for the locomotor capabilities of Australopithecus, including their capacity for endurance running and climbing.
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Affiliation(s)
- Ellison J McNutt
- Department of Integrative Anatomical Sciences, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Jeremy M DeSilva
- Department of Anthropology, Dartmouth College, Hanover, New Hampshire, USA
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21
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Moving Beyond the Obstetrical Dilemma Hypothesis: Birth, Weaning and Infant Care in the Plio-Pleistocene. THE MOTHER-INFANT NEXUS IN ANTHROPOLOGY 2020. [DOI: 10.1007/978-3-030-27393-4_10] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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22
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Nalley TK, Scott JE, Ward CV, Alemseged Z. Comparative morphology and ontogeny of the thoracolumbar transition in great apes, humans, and fossil hominins. J Hum Evol 2019; 134:102632. [DOI: 10.1016/j.jhevol.2019.06.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 06/19/2019] [Accepted: 06/19/2019] [Indexed: 01/01/2023]
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23
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Simpson SW, Levin NE, Quade J, Rogers MJ, Semaw S. Ardipithecus ramidus postcrania from the Gona Project area, Afar Regional State, Ethiopia. J Hum Evol 2019; 129:1-45. [DOI: 10.1016/j.jhevol.2018.12.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 11/26/2018] [Accepted: 12/05/2018] [Indexed: 11/30/2022]
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24
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DeSilva J, McNutt E, Benoit J, Zipfel B. One small step: A review of Plio‐Pleistocene hominin foot evolution. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2018; 168 Suppl 67:63-140. [DOI: 10.1002/ajpa.23750] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 10/01/2018] [Accepted: 10/05/2018] [Indexed: 01/03/2023]
Affiliation(s)
- Jeremy DeSilva
- Department of AnthropologyDartmouth College Hanover New Hampshire
- Evolutionary Studies Institute and School of GeosciencesUniversity of the Witwatersrand Johannesburg South Africa
| | - Ellison McNutt
- Department of AnthropologyDartmouth College Hanover New Hampshire
| | - Julien Benoit
- Evolutionary Studies Institute and School of GeosciencesUniversity of the Witwatersrand Johannesburg South Africa
| | - Bernhard Zipfel
- Evolutionary Studies Institute and School of GeosciencesUniversity of the Witwatersrand Johannesburg South Africa
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25
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Holowka NB, Lieberman DE. Rethinking the evolution of the human foot: insights from experimental research. J Exp Biol 2018; 221:221/17/jeb174425. [DOI: 10.1242/jeb.174425] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
ABSTRACT
Adaptive explanations for modern human foot anatomy have long fascinated evolutionary biologists because of the dramatic differences between our feet and those of our closest living relatives, the great apes. Morphological features, including hallucal opposability, toe length and the longitudinal arch, have traditionally been used to dichotomize human and great ape feet as being adapted for bipedal walking and arboreal locomotion, respectively. However, recent biomechanical models of human foot function and experimental investigations of great ape locomotion have undermined this simple dichotomy. Here, we review this research, focusing on the biomechanics of foot strike, push-off and elastic energy storage in the foot, and show that humans and great apes share some underappreciated, surprising similarities in foot function, such as use of plantigrady and ability to stiffen the midfoot. We also show that several unique features of the human foot, including a spring-like longitudinal arch and short toes, are likely adaptations to long distance running. We use this framework to interpret the fossil record and argue that the human foot passed through three evolutionary stages: first, a great ape-like foot adapted for arboreal locomotion but with some adaptations for bipedal walking; second, a foot adapted for effective bipedal walking but retaining some arboreal grasping adaptations; and third, a human-like foot adapted for enhanced economy during long-distance walking and running that had lost its prehensility. Based on this scenario, we suggest that selection for bipedal running played a major role in the loss of arboreal adaptations.
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Affiliation(s)
- Nicholas B. Holowka
- Department of Human Evolutionary Biology, Harvard University, 11 Divinity Ave, Cambridge, MA 02138, USA
| | - Daniel E. Lieberman
- Department of Human Evolutionary Biology, Harvard University, 11 Divinity Ave, Cambridge, MA 02138, USA
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