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Syeda SM, Tsegai ZJ, Cazenave M, Skinner MM, Kivell TL. Cortical bone architecture of hominid intermediate phalanges reveals functional signals of locomotion and manipulation. AMERICAN JOURNAL OF BIOLOGICAL ANTHROPOLOGY 2024; 184:e24902. [PMID: 38400773 DOI: 10.1002/ajpa.24902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 11/03/2023] [Accepted: 01/13/2024] [Indexed: 02/26/2024]
Abstract
OBJECTIVES Reconstruction of fossil hominin manual behaviors often relies on comparative analyses of extant hominid hands to understand the relationship between hand use and skeletal morphology. In this context, the intermediate phalanges remain understudied. Thus, here we investigate cortical bone morphology of the intermediate phalanges of extant hominids and compare it to the cortical structure of the proximal phalanges, to investigate the relationship between cortical bone structure and inferred loading during manual behaviors. MATERIALS AND METHODS Using micro-CT data, we analyze cortical bone structure of the intermediate phalangeal shaft of digits 2-5 in Pongo pygmaeus (n = 6 individuals), Gorilla gorilla (n = 22), Pan spp. (n = 23), and Homo sapiens (n = 23). The R package morphomap is used to study cortical bone distribution, cortical thickness and cross-sectional properties within and across taxa. RESULTS Non-human great apes generally have thick cortical bone on the palmar shaft, with Pongo only having thick cortex on the peaks of the flexor sheath ridges, while African apes have thick cortex along the entire flexor sheath ridge and proximal to the trochlea. Humans are distinct in having thicker dorsal shaft cortex as well as thick cortex at the disto-palmar region of the shaft. DISCUSSION Variation in cortical bone distribution and properties of the intermediate phalanges is consistent with differences in locomotor and manipulative behaviors in extant great apes. Comparisons between the intermediate and proximal phalanges reveals similar patterns of cortical bone distribution within each taxon but with potentially greater load experienced by the proximal phalanges, even in knuckle-walking African apes. This study provides a comparative context for the reconstruction of habitual hand use in fossil hominins and hominids.
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Affiliation(s)
- Samar M Syeda
- Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, UK
| | - Zewdi J Tsegai
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, Illinois, USA
| | - Marine Cazenave
- Department of Anatomy, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
- Department of Human Origins, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
- Division of Anthropology, American Museum of Natural History (AMNH), New York, USA
| | - Matthew M Skinner
- Department of Human Origins, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Tracy L Kivell
- Department of Human Origins, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
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Vanhoof MJM, Galletta L, Matthews H, De Groote I, Vereecke EE. Ulnar shape of extant primates: Functional signals and covariation with triquetrum shape. AMERICAN JOURNAL OF BIOLOGICAL ANTHROPOLOGY 2024; 183:e24755. [PMID: 37171151 DOI: 10.1002/ajpa.24755] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 03/27/2023] [Accepted: 04/26/2023] [Indexed: 05/13/2023]
Abstract
OBJECTIVES In this study, we investigated the shape differences of the distal ulna in a phylogenetic context among a broad range of primate taxa. Furthermore, we evaluated covariation between ulnar and triquetrum shape and a possible association between ulnar shape and locomotor behavior. MATERIALS AND METHODS We applied 3D geometric morphometrics on a large dataset comprising the distal ulna of 124 anthropoid primate specimens belonging to 12 different genera. For each species, a mean shape was calculated using 11 Procrustes-aligned surface landmarks on the distal ulna. These mean shapes are used in a bgPCA, pPCA, and PACA and 3D morphs were used to visualize more subtle differences between taxa. A p2B-PLS analysis was performed to test the covariance between distal ulnar and triquetrum shape. RESULTS The results show that more closely related species exhibit a similar distal ulnar shape. Overall, extant hominid ulnae show a shape shift compared to those of extant monkeys and hylobatids. This includes a shortening of the ulnar styloid process and dorspalmarly widening of the ulnar head, shape characteristics that are independent of phylogeny. Within the hominids, Pongo pygmaeus seem to possess the most plesiomorphic distal ulnar shape, while Gorilla and Homo sapiens display the most derived distal ulna. Cercopithecoids, hylobatids, and P. pygmaeus are characterized by a relatively deep ECU groove, which is a shape trait dependent of phylogeny. Although there was no significant covariation between distal ulnar shape and triquetrum shape, the shape differences of the distal ulna between the different primate taxa reveal a possible link with locomotor behavior. CONCLUSIONS The comparative analyses of this study reveal different shape trends in a phylogenetic context. Highly arboreal primates, such as hylobatids and Ateles fusciceps, show a distal ulnar morphology that appears to be adapted to tensile and torsional forces. In primates that use their wrist under more compressive conditions, such as quadrupedal cercopithecoids and great apes, the distal ulnar morphology seems to reflect increased compressive forces. In modern humans, the distal ulnar shape can be associated to enhanced manipulative skills and power grips. There was no significant covariation between distal ulnar shape and triquetrum shape, probably due to the variation in the amount of contact between the triquetrum and ulna. In combination with future research on wrist mobility in diverse primate taxa, the results of this study will allow us to establish form-function relationships of the primate wrist and contribute towards an evidence-based interpretation of fossil remains.
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Affiliation(s)
- Marie J M Vanhoof
- Department of Development & Regeneration, Biomedical Sciences Group, Kortrijk, Belgium
| | - Lorenzo Galletta
- School of Life and Environmental Sciences, Deakin University, Waurn Pounds, Victoria, Australia
| | - Harold Matthews
- Department of Human Genetics, Medical Imaging Center, Leuven, Belgium
| | - Isabelle De Groote
- Department of Archaeology, Ghent University, Belgium
- Research Centre in Evolutionary Anthropology and Paleoecology, Liverpool John Moores University, UK
| | - Evie E Vereecke
- Department of Development & Regeneration, Biomedical Sciences Group, Kortrijk, Belgium
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Syeda SM, Tsegai ZJ, Cazenave M, Skinner MM, Kivell TL. Cortical bone distribution of the proximal phalanges in great apes: implications for reconstructing manual behaviours. J Anat 2023; 243:707-728. [PMID: 37358024 PMCID: PMC10557399 DOI: 10.1111/joa.13918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 06/06/2023] [Accepted: 06/12/2023] [Indexed: 06/27/2023] Open
Abstract
Primate fingers are typically in direct contact with the environment during both locomotion and manipulation, and aspects of external phalangeal morphology are known to reflect differences in hand use. Since bone is a living tissue that can adapt in response to loading through life, the internal bone architecture of the manual phalanges should also reflect differences in manual behaviours. Here, we use the R package Morphomap to analyse high-resolution microCT scans of hominid proximal phalanges of digits 2-5 to determine whether cortical bone structure reflects variation in manual behaviours between bipedal (Homo), knuckle-walking (Gorilla, Pan) and suspensory (Pongo) taxa. We test the hypothesis that relative cortical bone distribution patterns and cross-sectional geometric properties will differ both among extant great apes and across the four digits due to locomotor and postural differences. Results indicate that cortical bone structure reflects the varied hand postures employed by each taxon. The phalangeal cortices of Pongo are significantly thinner and have weaker cross-sectional properties relative to the African apes, yet thick cortical bone under their flexor sheath ridges corresponds with predicted loading during flexed finger grips. Knuckle-walking African apes have even thicker cortical bone under the flexor sheath ridges, as well as in the region proximal to the trochlea, but Pan also has thicker diaphyseal cortices than Gorilla. Humans display a distinct pattern of distodorsal thickening, as well as relatively thin cortices, which may reflect the lack of phalangeal curvature combined with frequent use of flexed fingered hand grips during manipulation. Within each taxon, digits 2-5 have a similar cortical distribution in Pongo, Gorilla and, unexpectedly, Homo, which suggest similar loading of all fingers during habitual locomotion or hand use. In Pan, however, cortical thickness differs between the fingers, potentially reflecting differential loading during knuckle-walking. Inter- and intra-generic variation in phalangeal cortical bone structure reflects differences in manual behaviours, offering a comparative framework for reconstructing hand use in fossil hominins.
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Affiliation(s)
- Samar M. Syeda
- Skeletal Biology Research Centre, School of Anthropology and ConservationUniversity of KentCanterburyUK
| | - Zewdi J. Tsegai
- Department of Organismal Biology and AnatomyUniversity of ChicagoChicagoIllinoisUSA
| | - Marine Cazenave
- Skeletal Biology Research Centre, School of Anthropology and ConservationUniversity of KentCanterburyUK
- Division of AnthropologyAmerican Museum of Natural HistoryNew YorkNew YorkUSA
- Department of Anatomy, Faculty of Health SciencesUniversity of PretoriaPretoriaSouth Africa
| | - Matthew M. Skinner
- Skeletal Biology Research Centre, School of Anthropology and ConservationUniversity of KentCanterburyUK
| | - Tracy L. Kivell
- Department of Human OriginsMax Planck Institute for Evolutionary AnthropologyLeipzigGermany
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Dickinson E, Young MW, Flaim ND, Sawiec A, Granatosky MC. A functional framework for interpreting phalangeal form. J R Soc Interface 2023; 20:20230251. [PMID: 37582408 PMCID: PMC10427194 DOI: 10.1098/rsif.2023.0251] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 07/26/2023] [Indexed: 08/17/2023] Open
Abstract
Across tetrapods, the proportional lengths of the manual and pedal phalanges are highly constrained, following a generalized blueprint of shortening in a proximodistal gradient. Despite this, several lineages of both mammals (e.g. sloths, bats and colugos) and birds (e.g. raptors, parrots and woodpeckers) have broken this pattern, shortening the proximal phalanx while elongating more distal elements. As yet, no unifying explanation for this convergence has been empirically evaluated. This study combines a comparative phylogenetic assessment of phalangeal morphology across mammals and birds with a novel bioinspired robotics approach to explicitly test functional hypotheses relating to these morphotypes. We demonstrate that shortening the proximal phalanx allows taxa to maximize forces produced at the proximal interphalangeal joint, while elongation of subsequent elements maintains total ray length-ensuring arboreal species can still enclose large-diameter supports. Within suspensory and vertically clinging mammals, we additionally observe a secondary adaptation towards maximizing grip strength: namely increasing the height of the trochleae to increase the moment arm of digital flexor muscles that cross the joint. Together, our analyses highlight that numerous tetrapod lineages independently converged upon this morphotype to maximize proximal gripping strength, an adaptation to support specialized hunting and locomotor behaviours.
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Affiliation(s)
- Edwin Dickinson
- Department of Anatomy, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, NY, USA
| | - Melody W. Young
- Department of Anatomy, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, NY, USA
| | - Nicholas D. Flaim
- Department of Anatomy, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, NY, USA
| | - Aleksander Sawiec
- Department of Anatomy, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, NY, USA
- Center for Biomedical Innovation, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, NY, USA
| | - Michael C. Granatosky
- Department of Anatomy, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, NY, USA
- Center for Biomedical Innovation, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, NY, USA
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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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Wennemann SE, Lewton KL, Orr CM, Almécija S, Tocheri MW, Jungers WL, Patel BA. A geometric morphometric approach to investigate primate proximal phalanx diaphysis shape. AMERICAN JOURNAL OF BIOLOGICAL ANTHROPOLOGY 2022; 177:581-602. [PMID: 35755956 PMCID: PMC9231826 DOI: 10.1002/ajpa.24460] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Current approaches to quantify phalangeal curvature assume that the long axis of the bone's diaphysis approximates the shape of a portion of a circle (included angle method) or a parabola (second-degree polynomial method). Here we developed, tested, and employed an alternative geometric morphometrics-based approach to quantify diaphysis shape of proximal phalanges in humans, apes and monkeys with diverse locomotor behaviors. 100 landmarks of the central longitudinal axis were extracted from 3D surface models and analyzed using 2DGM methods, including Generalized Procrustes Analyses. Principal components analyses were performed and PC1 scores (>80% of variation) represented the dorsopalmar shape of the bone's central longitudinal axis and separated taxa consistently and in accord with known locomotor behavioral profiles. The most suspensory taxa, including orangutans, hylobatids and spider monkeys, had significantly lower PC1 scores reflecting the greatest amounts of phalangeal curvature. In contrast, bipedal humans and the quadrupedal cercopithecoid monkeys sampled (baboons, proboscis monkeys) exhibited significantly higher PC1 scores reflecting flatter phalanges. African ape (gorillas, chimpanzees and bonobos) phalanges fell between these two extremes and were not significantly different from each other. PC1 scores were significantly correlated with both included angle and the a coefficient of a second-degree polynomial calculated from the same landmark dataset, but had a significantly higher correlation with included angles. Our alternative approach for quantifying diaphysis shape of proximal phalanges to investigate dorsopalmar curvature is replicable and does not assume a priori either a circle or parabola model of shape, making it an attractive alternative compared with existing methodologies.
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Affiliation(s)
- Sophie E. Wennemann
- Department of Integrative Anatomical Sciences, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Kristi L. Lewton
- Department of Integrative Anatomical Sciences, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA,Human and Evolutionary Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Caley M. Orr
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO 80045, USA,Department of Anthropology, University of Colorado Denver, Denver, CO 80217, USA
| | - Sergio Almécija
- Division of Anthropology, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024, USA,New York Consortium in Evolutionary Primatology, New York, NY, USA,Institut Català de Paleontologia Miquel Crusafont, Universitat Autònoma de Barcelona, c/ Columnes s/n, Campus de la UAB, 08193, Cerdanyola del Vallès, Barcelona, Spain
| | - Matthew W. Tocheri
- Department of Anthropology, Lakehead University, Thunder Bay, Ontario P7B 5E1, Canada,Human Origins Program, National Museum of Natural History, Smithsonian Institution, Washington DC 20013, USA,Australian Research Council Centre of Excellence for Australian Biodiversity and Heritage, University of Wollongong, Wollongong, New South Wales, 2522, Australia
| | - William L. Jungers
- Department of Anatomical Sciences, Stony Brook University School of Medicine, Stony Brook, NY 11794, USA,Association Vahatra, BP 3972, Antananarivo 101, Madagascar
| | - Biren A. Patel
- Department of Integrative Anatomical Sciences, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA,Human and Evolutionary Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA,Corresponding author: Biren A. Patel, 1333 San Pablo Street, BMT 404, Keck School of Medicine, University of Southern California, Los Angeles CA, 90033, USA;
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van Heteren AH, Friess M, Détroit F, Balzeau A. Covariation of proximal finger and toe phalanges in Homo sapiens: A novel approach to assess covariation of serially corresponding structures. AMERICAN JOURNAL OF BIOLOGICAL ANTHROPOLOGY 2022; 177:471-488. [PMID: 36787692 DOI: 10.1002/ajpa.24439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 08/13/2021] [Accepted: 10/20/2021] [Indexed: 11/08/2022]
Abstract
OBJECTIVES As hands and feet are serially repeated corresponding structures in tetrapods, the morphology of fingers and toes is expected to covary due to a shared developmental origin. The present study focuses on the covariation of the shape of proximal finger and toe phalanges of adult Homo sapiens to determine whether covariation is different in the first ray relative to the others, as its morphology is also different. MATERIAL AND METHODS Proximal phalanges of 76 individuals of unknown sex (Muséum national d'Histoire naturelle, Paris, and the Natural History Museum, London) were digitized using a surface scanner. Landmarks were positioned on 3D surface models of the phalanges. Generalized Procrustes analysis and two-block partial least squares (PLS) analyses were conducted. A novel landmark-based geometric morphometric approach focusing on covariation is based on a PCoA of the angles between PLS axes in morphospace. The results can be statistically evaluated. RESULTS The difference in PCo scores between the first and the other rays indicates that the integration between the thumb and the big toe is different from that between the lateral rays of the hand and foot. DISCUSSION We speculate that the results are possibly the evolutionary consequence of differential selection pressure on the big toe relative to the other toes related to the rise of bipedalism, which is proposed to have emerged very early in the hominin clade. In contrast, thumb morphology and its precision grip never ceased undergoing changes, suggesting less acute selection pressures related to the evolution of the precision grip.
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Affiliation(s)
- Anneke H van Heteren
- PaleoFED Team, UMR 7194, CNRS, Département Homme et Environnement, Muséum National d'Histoire Naturelle, Musée de l'Homme, 17, Place du Trocadéro, Paris, 75016, France
| | - Martin Friess
- Éco-Anthropologie, UMR 7206, CNRS, Département Homme et Environnement, Muséum National d'Histoire Naturelle, Université de Paris, Paris, 75016, France
| | - Florent Détroit
- PaleoFED Team, UMR 7194, CNRS, Département Homme et Environnement, Muséum National d'Histoire Naturelle, Musée de l'Homme, 17, Place du Trocadéro, Paris, 75016, France
| | - Antoine Balzeau
- PaleoFED Team, UMR 7194, CNRS, Département Homme et Environnement, Muséum National d'Histoire Naturelle, Musée de l'Homme, 17, Place du Trocadéro, Paris, 75016, France.,Department of African Zoology, Royal Museum for Central Africa, Leuvensesteenweg 13, Tervuren, 3080, Belgium
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8
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Everett MC, Elliott MC, Gaynor D, Hill AC, Syeda SM, Casana J, Zipfel B, DeSilva JM, Dominy NJ. Mechanical loading of primate fingers on vertical rock surfaces. S AFR J SCI 2021. [DOI: 10.17159/sajs.2021/10409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Mechanical loading of finger bones (phalanges) can induce angular curvature, which benefits arboreal primates by dissipating forces and economising the recruitment of muscles during climbing. The recent discovery of extremely curved phalanges in a hominin, Homo naledi, is puzzling, for it suggests life in an arboreal milieu, or, alternatively, habitual climbing on vertical rock surfaces. The importance of climbing rock walls is attested by several populations of baboons, one of which uses a 7-m vertical surface to enter and exit Dronkvlei Cave, De Hoop Nature Reserve, South Africa. This rock surface is an attractive model for estimating the probability of extreme mechanical loading on the phalanges of rock-climbing primates. Here we use three-dimensional photogrammetry to show that 82–91% of the climbable surface would generate high forces on the flexor tendon pulley system and severely load the phalanges of baboons and H. naledi. If such proportions are representative of vertical rock surfaces elsewhere, it may be sufficient to induce stress-mitigating curvature in the phalanges of primates.
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Affiliation(s)
- Michael C. Everett
- Department of Anthropology, Dartmouth College, Hanover, New Hampshire, USA
| | - Marina C. Elliott
- Department of Archaeology, Simon Fraser University, Burnaby, British Columbia, Canada
- Centre for the Exploration of the Deep Human Journey, University of the Witwatersrand, Johannesburg, South Africa
| | - David Gaynor
- Mammal Research Institute, University of Pretoria, Pretoria, South Africa
| | - Austin C. Hill
- Department of Anthropology, Dartmouth College, Hanover, New Hampshire, USA
- Department of Anthropology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Samar M. Syeda
- Department of Anthropology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Jesse Casana
- Department of Anthropology, Dartmouth College, Hanover, New Hampshire, USA
| | - Bernhard Zipfel
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa
| | - Jeremy M. DeSilva
- Department of Anthropology, Dartmouth College, Hanover, New Hampshire, USA
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa
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9
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Vanhoof MJM, Galletta L, De Groote I, Vereecke EE. Functional signals and covariation in triquetrum and hamate shape of extant primates using 3D geometric morphometrics. J Morphol 2021; 282:1382-1401. [PMID: 34219278 DOI: 10.1002/jmor.21393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 06/18/2021] [Accepted: 06/28/2021] [Indexed: 11/10/2022]
Abstract
In this study, we want to investigate the covariation in the shape of two carpal bones, the triquetrum and hamate, and the possible association with locomotor behavior in a broad range of primate taxa. We applied 3D Geometric Morphometrics on a large data set comprising 309 anthropoid primates of 12 different genera. Principal component analyses were performed on the covariance matrix of 18 (triquetrum) and 23 (hamate) Procrustes-aligned surface landmarks. A two-block partial least square analysis was done to test the covariance between triquetrum and hamate shape, without relying on the predictive models implicit in regression analyses. The results show that the carpal shape of quadrupedal anthropoids, which mainly use their wrist under compressive conditions, differs from that of suspensory primates as their wrist is possibly subjected to tensile and torsional forces. Within the hominids, differences in shape also distinguish more terrestrial from more arboreal species. Even within the great apes, we are able to capture shape differences between species of the same genus. In combination with behavioral and biomechanical studies, the results of this research can be used to establish form-function relationships of the primate hand which will aid the functional interpretation of primate fossil remains.
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Affiliation(s)
- Marie J M Vanhoof
- Department of Development & Regeneration, Biomedical Sciences Group, KU Leuven Campus Kulak, Kortrijk, Belgium
| | - Lorenzo Galletta
- School of Life and Environmental Sciences, Deakin University, Waurn Pounds, Victoria, Australia
| | - Isabelle De Groote
- Department of Archaeology, Ghent University, Ghent, Belgium.,Research Centre in Evolutionary Anthropology and Paleoecology, Liverpool John Moores University, Liverpool, UK
| | - Evie E Vereecke
- Department of Development & Regeneration, Biomedical Sciences Group, KU Leuven Campus Kulak, Kortrijk, Belgium
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Phalangeal curvature in a chimpanzee raised like a human: Implications for inferring arboreality in fossil hominins. Proc Natl Acad Sci U S A 2020; 117:11223-11225. [PMID: 32393625 PMCID: PMC7260939 DOI: 10.1073/pnas.2004371117] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Arboreal primates such as chimpanzees exhibit pronounced curvature in their hand and foot phalanges, which is assumed to develop throughout life in response to mechanical loads produced by grasping and hanging from branches. Intriguingly, ancient fossil hominins also exhibit substantial phalangeal curvature, which, too, has been interpreted as a direct result of habitual arboreality during life. Here, we describe the phalangeal curvature of a chimpanzee who was raised during the 1930s in New York City to live much like a human, including by having very few opportunities to engage in arboreal activities. We show that the degree of hand and foot phalangeal curvature in this individual is indistinguishable from that of wild chimpanzees and distinct from humans. Thus, rather than being a direct effect of mechanical loads produced by lifetime arboreal activities, phalangeal curvature appears to be shaped largely by genetic factors. An important implication of this finding is that phalangeal curvature among fossil hominins is evidently best interpreted as a primitive trait inherited from an arboreal ancestral species rather than proof of engagement in arboreal activities during life.
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11
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Brzobohatá H, Krajíček V, Velemínský P, Velemínská J. Three-dimensional geometry of human tibial anterior curvature in chronologically distinct population samples of Central Europeans (2900 BC - 21 st century AD). Sci Rep 2019; 9:4234. [PMID: 30862871 PMCID: PMC6414627 DOI: 10.1038/s41598-019-40625-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Accepted: 01/28/2019] [Indexed: 12/24/2022] Open
Abstract
Several lines of bioarchaeological research have confirmed the gradual decline in lower limb loading among past human populations, beginning with the transition to agriculture. The goal of this study was to assess whether human tibial curvature reflects this decline, with a special emphasis on the time-span during which the pace of technological change has been the most rapid. Our study is the first (1) to apply longitudinal curvature analysis in the antero-posterior (A–P) and medio-lateral (M–L) planes to the human tibia, and (2) that incorporates a broad temporal population sample including the periods of intensification of agriculture, urbanization and industrialization (from 2900 BC to the 21st century AD; N = 435) within Czech territories. Using three-dimensional geometric morphometrics, we investigated whether anterior tibial curvature mirrors assumed diminishing lower limb loading between prehistoric and industrialized societies and explored its shape in all three dimensions. Results showed the continuous trend of A–P straightening of the shaft. This straightening was associated with a relative sigmoidal curve accentuation in the M-L plane. Given the timescale involved and the known phenomenon of declining mobility, such adaptive changes in bone geometry can be interpreted in terms of the diminishing biomechanical demands on the tibia under different living conditions.
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Affiliation(s)
- Hana Brzobohatá
- Department of Prehistorical Archaeology, Institute of Archaeology of the Academy of Sciences, Prague, Czech Republic.
| | - Václav Krajíček
- Department of Anthropology and Human Genetics, Faculty of Science, Charles University, Prague, Czech Republic
| | - Petr Velemínský
- Department of Anthropology, National Museum, Prague, Czech Republic
| | - Jana Velemínská
- Department of Anthropology and Human Genetics, Faculty of Science, Charles University, Prague, Czech Republic
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Brzobohatá H, Krajíček V, Velemínský P, Velemínská J. Three-dimensional geometry of human tibial anterior curvature in chronologically distinct population samples of Central Europeans (2900 BC - 21 st century AD). Sci Rep 2019. [PMID: 30862871 DOI: 10.1038/s41598−019−40625−3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/14/2023] Open
Abstract
Several lines of bioarchaeological research have confirmed the gradual decline in lower limb loading among past human populations, beginning with the transition to agriculture. The goal of this study was to assess whether human tibial curvature reflects this decline, with a special emphasis on the time-span during which the pace of technological change has been the most rapid. Our study is the first (1) to apply longitudinal curvature analysis in the antero-posterior (A-P) and medio-lateral (M-L) planes to the human tibia, and (2) that incorporates a broad temporal population sample including the periods of intensification of agriculture, urbanization and industrialization (from 2900 BC to the 21st century AD; N = 435) within Czech territories. Using three-dimensional geometric morphometrics, we investigated whether anterior tibial curvature mirrors assumed diminishing lower limb loading between prehistoric and industrialized societies and explored its shape in all three dimensions. Results showed the continuous trend of A-P straightening of the shaft. This straightening was associated with a relative sigmoidal curve accentuation in the M-L plane. Given the timescale involved and the known phenomenon of declining mobility, such adaptive changes in bone geometry can be interpreted in terms of the diminishing biomechanical demands on the tibia under different living conditions.
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Affiliation(s)
- Hana Brzobohatá
- Department of Prehistorical Archaeology, Institute of Archaeology of the Academy of Sciences, Prague, Czech Republic.
| | - Václav Krajíček
- Department of Anthropology and Human Genetics, Faculty of Science, Charles University, Prague, Czech Republic
| | - Petr Velemínský
- Department of Anthropology, National Museum, Prague, Czech Republic
| | - Jana Velemínská
- Department of Anthropology and Human Genetics, Faculty of Science, Charles University, Prague, Czech Republic
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Bardo A, Vigouroux L, Kivell TL, Pouydebat E. The impact of hand proportions on tool grip abilities in humans, great apes and fossil hominins: A biomechanical analysis using musculoskeletal simulation. J Hum Evol 2018; 125:106-121. [PMID: 30502891 DOI: 10.1016/j.jhevol.2018.10.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 10/02/2018] [Accepted: 10/03/2018] [Indexed: 10/27/2022]
Abstract
Differences in grip techniques used across primates are usually attributed to variation in thumb-finger proportions and muscular anatomy of the hand. However, this cause-effect relationship is not fully understood because little is known about the biomechanical functioning and mechanical loads (e.g., muscle or joint forces) of the non-human primate hand compared to that of humans during object manipulation. This study aims to understand the importance of hand proportions on the use of different grip strategies used by humans, extant great apes (bonobos, gorillas and orangutans) and, potentially, fossil hominins (Homo naledi and Australopithecus sediba) using a musculoskeletal model of the hand. Results show that certain grips are more challenging for some species, particularly orangutans, than others, such that they require stronger muscle forces for a given range of motion. Assuming a human-like range of motion at each hand joint, simulation results show that H. naledi and A. sediba had the biomechanical potential to use the grip techniques considered important for stone tool-related behaviors in humans. These musculoskeletal simulation results shed light on the functional consequences of the different hand proportions among extant and extinct hominids and the different manipulative abilities found in humans and great apes.
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Affiliation(s)
- Ameline Bardo
- Paris Descartes University, Sorbonne Paris Cité, Paris, 75006, France; Department of Adaptations du Vivant, UMR 7179-CNRS/MNHN, MECADEV, Paris, 75321, France; Animal Postcranial Evolution Laboratory, Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, Kent, CT2 7NR, United Kingdom.
| | - Laurent Vigouroux
- Institute of Movement Sciences, UMR 7287-CNRS, Aix-Marseille University, Marseille, 13288, France
| | - Tracy L Kivell
- Animal Postcranial Evolution Laboratory, Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, Kent, CT2 7NR, United Kingdom; Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, D-04103 Leipzig, Germany; Evolutionary Studies Institute and Centre for Excellence in PalaeoSciences, University of the Witwatersrand, Private Bag 3, Wits 2050, South Africa
| | - Emmanuelle Pouydebat
- Department of Adaptations du Vivant, UMR 7179-CNRS/MNHN, MECADEV, Paris, 75321, France
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Rein TR. A Geometric Morphometric Examination of Hominoid Third Metacarpal Shape and Its Implications for Inferring the Precursor to Terrestrial Bipedalism. Anat Rec (Hoboken) 2018; 302:983-998. [DOI: 10.1002/ar.23985] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2016] [Revised: 06/07/2018] [Accepted: 06/14/2018] [Indexed: 11/07/2022]
Affiliation(s)
- Thomas R. Rein
- Department of Anthropology Central Connecticut State University New Britain Connecticut
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15
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New hominin postcranial remains from locality OMO 323, Shungura Formation, Lower Omo Valley, southwestern Ethiopia. J Hum Evol 2018; 122:23-32. [PMID: 29706229 DOI: 10.1016/j.jhevol.2018.03.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Revised: 03/27/2018] [Accepted: 03/28/2018] [Indexed: 11/23/2022]
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Neufuss J, Robbins MM, Baeumer J, Humle T, Kivell TL. Comparison of hand use and forelimb posture during vertical climbing in mountain gorillas (Gorilla beringei beringei) and chimpanzees (Pan troglodytes). AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2017; 164:651-664. [PMID: 28872656 DOI: 10.1002/ajpa.23303] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 08/01/2017] [Accepted: 08/14/2017] [Indexed: 11/11/2022]
Abstract
OBJECTIVES Studies on grasping and limb posture during arboreal locomotion in great apes in their natural environment are scarce and thus, attempts to correlate behavioral and habitat differences with variation in morphology are limited. The aim of this study is to compare hand use and forelimb posture during vertical climbing in wild, habituated mountain gorillas (Gorilla beringei beringei) and semi-free-ranging chimpanzees (Pan troglodytes) to assess differences in the climbing styles that may relate to variation in hand or forelimb morphology and body size. MATERIALS AND METHODS We investigated hand use and forelimb posture during both ascent and descent vertical climbing in 15 wild mountain gorillas and eight semi-free-ranging chimpanzees, using video records obtained ad libitum. RESULTS In both apes, forelimb posture was correlated with substrate size during both ascent and descent climbing. While climbing, both apes used power grips and diagonal power grips, including three different thumb postures. Mountain gorillas showed greater ulnar deviation of the wrist during vertical descent than chimpanzees, and the thumb played an important supportive role when gorillas vertically descended lianas. DISCUSSION We found that both apes generally had the same grip preferences and used similar forelimb postures on supports of a similar size, which is consistent with their overall similarity in hard and soft tissue morphology of the hand and forelimb. However, some species-specific differences in morphology appear to elicit slightly different grasping strategies during vertical climbing between mountain gorillas and chimpanzees.
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Affiliation(s)
- Johanna Neufuss
- Animal Postcranial Evolution (APE) Laboratory, Skeletal Biology Research Centre, School of Anthropology & Conservation, University of Kent, Canterbury, United Kingdom
| | - Martha M Robbins
- Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Jana Baeumer
- Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Tatyana Humle
- Durrell Institute of Conservation and Ecology, School of Anthropology & Conservation, University of Kent, Canterbury, United Kingdom
| | - Tracy L Kivell
- Animal Postcranial Evolution (APE) Laboratory, Skeletal Biology Research Centre, School of Anthropology & Conservation, University of Kent, Canterbury, United Kingdom.,Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
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Functional Morphology of the Primate Hand: Recent Approaches Using Biomedical Imaging, Computer Modeling, and Engineering Methods. ACTA ACUST UNITED AC 2016. [DOI: 10.1007/978-1-4939-3646-5_9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2023]
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18
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Morphological Diversity in the Digital Rays of Primate Hands. DEVELOPMENTS IN PRIMATOLOGY: PROGRESS AND PROSPECTS 2016. [DOI: 10.1007/978-1-4939-3646-5_4] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Godfrey LR, Granatosky MC, Jungers WL. The Hands of Subfossil Lemurs. DEVELOPMENTS IN PRIMATOLOGY: PROGRESS AND PROSPECTS 2016. [DOI: 10.1007/978-1-4939-3646-5_15] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
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Domínguez-Rodrigo M, Pickering TR, Almécija S, Heaton JL, Baquedano E, Mabulla A, Uribelarrea D. Earliest modern human-like hand bone from a new >1.84-million-year-old site at Olduvai in Tanzania. Nat Commun 2015; 6:7987. [PMID: 26285128 PMCID: PMC4557276 DOI: 10.1038/ncomms8987] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 07/03/2015] [Indexed: 11/09/2022] Open
Abstract
Modern humans are characterized by specialized hand morphology that is associated with advanced manipulative skills. Thus, there is important debate in paleoanthropology about the possible cause–effect relationship of this modern human-like (MHL) hand anatomy, its associated grips and the invention and use of stone tools by early hominins. Here we describe and analyse Olduvai Hominin (OH) 86, a manual proximal phalanx from the recently discovered >1.84-million-year-old (Ma) Philip Tobias Korongo (PTK) site at Olduvai Gorge (Tanzania). OH 86 represents the earliest MHL hand bone in the fossil record, of a size and shape that differs not only from all australopiths, but also from the phalangeal bones of the penecontemporaneous and geographically proximate OH 7 partial hand skeleton (part of the Homo habilis holotype). The discovery of OH 86 suggests that a hominin with a more MHL postcranium co-existed with Paranthropus boisei and Homo habilis at Olduvai during Bed I times. The homin fossil record reveals a complex pattern of hand evolution. Here, the authors describe a phalanx of a >1.84-million-year-old unidentified hominin, which represents the earliest modern human like hand bone in the fossil record.
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Affiliation(s)
- Manuel Domínguez-Rodrigo
- 1] IDEA (Instituto de Evolución en África), Museo de los Orígenes, Plaza de San Andrés 2, 28005 Madrid, Spain [2] Department of Prehistory, Complutense University, Prof. Aranguren s/n, 28040 Madrid, Spain
| | - Travis Rayne Pickering
- 1] Department of Anthropology, University of Wisconsin-Madison, 1180 Observatory Drive, Madison, Wisconsin 53706, USA [2] Evolutionary Studies Institute, University of the Witwatersrand, WITS, 2050 Johannesburg, South Africa [3] Plio-Pleistocene Palaeontology Section, Department of Vertebrates, Ditsong National Museum of Natural History (Transvaal Museum), Pretoria 0002, South Africa
| | - Sergio Almécija
- 1] Center for the Advanced Study of Human Paleobiology, Department of Anthropology, The George Washington University, Washington, District of Columbia 20052, USA [2] Department of Anatomical Sciences, Stony Brook University, Stony Brook, New York 11794-8081, USA [3] Institut Català de Paleontologia Miquel Crusafont (ICP), Universitat Autònoma de Barcelona, Edifici Z (ICTA-ICP), campus de la UAB, c/ de les Columnes, s/n, 08193 Cerdanyola del Vallès (Barcelona), Spain
| | - Jason L Heaton
- 1] Evolutionary Studies Institute, University of the Witwatersrand, WITS, 2050 Johannesburg, South Africa [2] Plio-Pleistocene Palaeontology Section, Department of Vertebrates, Ditsong National Museum of Natural History (Transvaal Museum), Pretoria 0002, South Africa [3] Department of Biology, Birmingham-Southern College, Birmingham, Alabama 35254, USA
| | - Enrique Baquedano
- 1] IDEA (Instituto de Evolución en África), Museo de los Orígenes, Plaza de San Andrés 2, 28005 Madrid, Spain [2] Museo Arqueológico Regional, Plaza de las Bernardas s/n, 28801 Alcalá de Henares, Madrid, Spain
| | - Audax Mabulla
- Archaeology Unit, University of Dar es Salaam, Dar es Salaam, PO Box 35050 Tanzania
| | - David Uribelarrea
- Department of Geodynamics, Complutense University, c/ José Antonio Novás 12, 28040 Madrid, Spain
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Lorenzo C, Pablos A, Carretero JM, Huguet R, Valverdú J, Martinón-Torres M, Arsuaga JL, Carbonell E, Bermúdez de Castro JM. Early Pleistocene human hand phalanx from the Sima del Elefante (TE) cave site in Sierra de Atapuerca (Spain). J Hum Evol 2015; 78:114-21. [DOI: 10.1016/j.jhevol.2014.08.007] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Revised: 08/12/2014] [Accepted: 08/12/2014] [Indexed: 11/16/2022]
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de Bonis L, Koufos GD. First discovery of postcranial bones of Ouranopithecus macedoniensis (Primates, Hominoidea) from the late Miocene of Macedonia (Greece). J Hum Evol 2014; 74:21-36. [DOI: 10.1016/j.jhevol.2014.05.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2012] [Revised: 03/20/2014] [Accepted: 05/16/2014] [Indexed: 11/28/2022]
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Huynh Nguyen N, Pahr DH, Gross T, Skinner MM, Kivell TL. Micro-finite element (μFE) modeling of the siamang (Symphalangus syndactylus) third proximal phalanx: the functional role of curvature and the flexor sheath ridge. J Hum Evol 2014; 67:60-75. [PMID: 24496040 DOI: 10.1016/j.jhevol.2013.12.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Revised: 10/22/2013] [Accepted: 12/10/2013] [Indexed: 10/25/2022]
Abstract
Phalangeal curvature is a commonly used morphological feature for the interpretation of extant and fossil primate locomotor behaviour. Here, we build on a recent biomechanical study (Richmond, 2007) in two ways: first, we use a 3D micro-FE model, which models the real internal microstructure (i.e., cortical thickness and trabecular bone structure) and, second, we model four siamang third proximal phalanges. We test identical 2D homogenized FE models and two 3D micro-FE phalanx models that are mathematically straightened to isolate the biomechanical significance of curvature. We further investigate how varying the loading configuration (e.g., boundary constraints) and modeling (e.g., 2D versus 3D) affects the biomechanical behaviour of the phalanx. Finally, we examine how intraspecific variation in external and internal bony morphology affects the biomechanical behaviour of the phalanx. Simulation results demonstrate that the general pattern of strain and displacement is similar between the 3D micro-FE and 2D homogenized FE models but the absolute values differ substantially. The biomechanical behaviour of the 3D FE models more closely match the relative strain patterns from the validation experiment than the 2D homogenized FE models, indicating the 3D microstructure model is preferable. Varying the loading configuration can have dramatic effects on the biomechanical behaviour of the phalanx depending on individual morphology, but overall a cantilevered beam model is an equally valid, if not better, configuration for modeling the phalanx as other previously-proposed models. Variation in flexor ridge morphology has a substantial effect on phalanx strain; the taller the ridge, the less strain incurred by other regions of the palmar shaft. Finally, phalangeal curvature reduces overall strain experienced by the phalanx, but does not necessarily reduce bending or increase the compression-to-tension ratio. These results confirm the adaptive role of phalangeal curvature during flexed-finger grasping postures and demonstrate that modeling variation in cortical thickness and flexor ridge morphology improves the behaviour of the FE model, which has important implications for the functional interpretation of phalanx form.
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Affiliation(s)
- N Huynh Nguyen
- Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, Leipzig 04103, Germany.
| | - Dieter H Pahr
- Institute of Lightweight Design and Structural Biomechanics, Vienna University of Technology, Gusshausstrasse 27-29, A-1040 Vienna, Austria.
| | - Thomas Gross
- Institute of Lightweight Design and Structural Biomechanics, Vienna University of Technology, Gusshausstrasse 27-29, A-1040 Vienna, Austria.
| | - Matthew M Skinner
- Department of Anthropology, University College London, 14 Taviton Street, London WC1H 0BW, UK; Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, Leipzig 04103, Germany.
| | - Tracy L Kivell
- Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, Leipzig 04103, Germany; School of Anthropology and Conservation, University of Kent, Marlowe Building, Canterbury, Kent CT2 7NR, UK.
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Almécija S, Shrewsbury M, Rook L, Moyà-Solà S. The morphology of Oreopithecus bambolii pollical distal phalanx. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2014; 153:582-97. [PMID: 24395731 DOI: 10.1002/ajpa.22458] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Revised: 11/16/2013] [Accepted: 11/25/2013] [Indexed: 11/08/2022]
Abstract
Oreopithecus bambolii is a Late Miocene ape from Italy, first described in the late 19th century. Its interpretation is still highly controversial, especially in reference to its hand proportions and thumb morphology. In this study, the authors provide detailed descriptions of the available Oreopithecus pollical distal phalanx (PDP) specimens, as well as bivariate and multivariate morphometric analyses in comparison with humans, extant apes, selected anthropoid monkeys, and available Miocene PDP specimens. The multivariate results reveal two opposite poles on the hominoid PDP shape spectrum: on one side, a mediolaterally broad and dorsopalmarly short human PDP, and on the other side, the narrow and "conical" PDP of chimpanzees and orangutans. The authors contend that Oreopithecus exhibits intermediate PDP proportions that are largely primitive for hominoids because it shares morphological similarities with Proconsul. Furthermore, Oreopithecus displays a mediolaterally wide tuft for a hominoid, as well as a palmarly elevated attachment for a long tendon of a flexor muscle that is associated at its proximal edge with a proximal fossa and at its distal edge with an ungual fossa. These nonmetrical traits have been associated in humans with their capability to oppose and contact the proximal pads of the thumb and fingers, that is, pad-to-pad precision grasping. These traits reinforce previous studies that indicate a human-like thumb-to-hand length ratio compatible with pad-to-pad precision grasping in Oreopithecus. Although specific hand use is still unresolved in Oreopithecus, the results suggest enhanced manipulative skills (unrelated to stone tool-making) in this taxon relative to other (extant or fossil) hominoids.
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Affiliation(s)
- Sergio Almécija
- Department of Anatomical Sciences, Stony Brook University School of Medicine, Stony Brook, NY, 11794-8081; Department of Vertebrate Paleontology, American Museum of Natural History and NYCEP, New York, NY, 10024; Institut Català de Paleontologia Miquel Crusafont, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, 08193, Spain
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Jade S, Tamvada KH, Strait DS, Grosse IR. Finite element analysis of a femur to deconstruct the paradox of bone curvature. J Theor Biol 2013; 341:53-63. [PMID: 24099719 DOI: 10.1016/j.jtbi.2013.09.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Revised: 09/06/2013] [Accepted: 09/11/2013] [Indexed: 10/26/2022]
Abstract
Most long limb bones in terrestrial mammals exhibit a longitudinal curvature and have been found to be loaded in bending. Bone curvature poses a paradox in terms of the mechanical function of limb bones, for many believe the curvature in these bones increases bending stress, potentially reducing the bone's load carrying capacity (i.e., its mechanical strength). The aim of this study is to investigate the role of longitudinal bone curvature in the design of limb bones. In particular, it has been hypothesized that bone curvature results in a trade-off between the bone's mechanical strength and its bending predictability. We employed finite element analysis (FEA) of abstract and realistic human femora to address this issue. Geometrically simplified human femur models with different curvatures were developed and analyzed with a commercial FEA tool to examine how curvature affects the bone's bending predictability and load carrying capacity. Results were post-processed to yield probability density functions (PDFs) describing the circumferential location of maximum equivalent stress for various curvatures in order to assess bending predictability. To validate our findings, a finite element model was built from a CT scan of a real human femur and compared to the simplified femur model. We found general agreement in trends but some quantitative differences most likely due to the geometric differences between the digitally reconstructed and the simplified finite element models. As hypothesized by others, our results support the hypothesis that bone curvature can increase bending predictability, but at the expense of bone strength.
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Affiliation(s)
- Sameer Jade
- Department of Mechanical and Industrial Engineering, 160 Governor's Drive, University of Massachusetts, Amherst, MA 01003, USA
| | - Kelli H Tamvada
- Department of Anthropology, Arts and Sciences 237, 1400 Washington Ave., University of Albany, NY 12222, USA
| | - David S Strait
- Department of Anthropology, Arts and Sciences 237, 1400 Washington Ave., University of Albany, NY 12222, USA
| | - Ian R Grosse
- Department of Mechanical and Industrial Engineering, 160 Governor's Drive, University of Massachusetts, Amherst, MA 01003, USA.
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A closer look at the “Protopithecus” fossil assemblages: new genus and species from Bahia, Brazil. J Hum Evol 2013; 65:374-90. [DOI: 10.1016/j.jhevol.2013.07.008] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Revised: 07/08/2013] [Accepted: 07/15/2013] [Indexed: 11/17/2022]
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Rein TR, McCarty LA. Metacarpophalangeal Joint Orientation in Anthropoid Manual Phalanges. Anat Rec (Hoboken) 2012; 295:2057-68. [DOI: 10.1002/ar.22600] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2011] [Accepted: 07/20/2012] [Indexed: 11/08/2022]
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Congdon KA. Interspecific and Ontogenetic Variation in Proximal Pedal Phalangeal Curvature of Great Apes (Gorilla gorilla, Pan troglodytes, and Pongo pygmaeus). INT J PRIMATOL 2012. [DOI: 10.1007/s10764-012-9590-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Halenar LB. Reconstructing the locomotor repertoire of Protopithecus brasiliensis. II. Forelimb morphology. Anat Rec (Hoboken) 2011; 294:2048-63. [PMID: 22042627 DOI: 10.1002/ar.21499] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2011] [Accepted: 09/16/2011] [Indexed: 11/06/2022]
Abstract
The majority of previous publications have suggested that the large-bodied subfossil Protopithecus brasiliensis was a suspensory ateline with a locomotor repertoire similar to that of extant Ateles and Brachyteles. This is unexpected, as the cranial morphology of Protopithecus is very similar to Alouatta, a genus usually classified as a deliberate quadrupedal climber. Complicating matters further, as Protopithecus is twice as large as Ateles and Brachyteles, its ability to be as suspensory as those two genera is suspect and a terrestrial component of the locomotor repertoire has also been hypothesized. The forelimbs of Protopithecus, while relatively elongated as would be expected in a suspensory animal, are also quite robust and show several adaptations for climbing. To test these hypotheses about the fossil locomotor repertoire, three-dimensional geometric morphometric techniques were used to quantify the shapes of the fossil distal humerus and proximal ulna and then compare them to a broad sample of extant primates with varying body sizes and locomotor patterns. Results indicate that Protopithecus is similar to Ateles and Brachyteles in terms of its forelimb joint surface morphology; however, the overall locomotor repertoire of the fossil is reconstructed as more flexible to include forelimb suspension, climbing, and potentially some terrestrial ground use. The combination of suspensory locomotion and quadrupedal climbing supported here indicates the beginnings of the evolutionary transition from a more acrobatic style of locomotion in the last common ancestor of alouattins and atelins to the current pattern of howler locomotion.
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Affiliation(s)
- Lauren B Halenar
- The Graduate Center, Department of Anthropology, City University of New York, New York Consortium in Evolutionary Primatology, USA.
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Rein TR, Harrison T, Zollikofer CP. Skeletal correlates of quadrupedalism and climbing in the anthropoid forelimb: Implications for inferring locomotion in Miocene catarrhines. J Hum Evol 2011; 61:564-74. [DOI: 10.1016/j.jhevol.2011.07.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2011] [Revised: 05/02/2011] [Accepted: 07/21/2011] [Indexed: 10/17/2022]
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Rein TR. The correspondence between proximal phalanx morphology and locomotion: Implications for inferring the locomotor behavior of fossil catarrhines. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2011; 146:435-45. [DOI: 10.1002/ajpa.21599] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2010] [Accepted: 07/18/2011] [Indexed: 11/08/2022]
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Locomotor inferences in Pierolapithecus and Hispanopithecus: Reply to Deane and Begun (2008). J Hum Evol 2010; 59:143-9; discussion 150-4. [DOI: 10.1016/j.jhevol.2010.02.002] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2008] [Revised: 10/13/2009] [Accepted: 10/01/2009] [Indexed: 11/18/2022]
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De Groote I, Lockwood CA, Aiello LC. Technical note: A new method for measuring long bone curvature using 3D landmarks and semi-landmarks. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2010; 141:658-64. [DOI: 10.1002/ajpa.21225] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Almécija S, Alba DM, Moyà-Solà S. Pierolapithecus and the functional morphology of Miocene ape hand phalanges: paleobiological and evolutionary implications. J Hum Evol 2009; 57:284-97. [DOI: 10.1016/j.jhevol.2009.02.008] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2008] [Revised: 02/03/2009] [Accepted: 02/18/2009] [Indexed: 10/20/2022]
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Galtés I, Jordana X, Manyosa J, Malgosa A. Functional implications of radial diaphyseal curvature. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2009; 138:286-92. [DOI: 10.1002/ajpa.20926] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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36
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Descriptions of the upper limb skeleton of Homo floresiensis. J Hum Evol 2008; 57:555-70. [PMID: 19056103 DOI: 10.1016/j.jhevol.2008.06.007] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2008] [Revised: 05/12/2008] [Accepted: 06/05/2008] [Indexed: 11/20/2022]
Abstract
Several bones of the upper extremity were recovered during excavations of Late Pleistocene deposits at Liang Bua, Flores, and these have been attributed to Homo floresiensis. At present, these upper limb remains have been assigned to six different individuals - LB1, LB2, LB3, LB4, LB5, and LB6. Several of these bones are complete or nearly so, but some are quite fragmentary. All skeletal remains recovered from Liang Bua were extremely fragile, but have now been stabilized and hardened in the laboratory in Jakarta. They are now curated in museum-quality containers at the National Research and Development Centre for Archaeology in Jakarta, Indonesia. These skeletal remains are described and illustrated photographically. The upper limb presents a unique mosaic of derived (human-like) and primitive morphologies, the combination of which is never found in either healthy or pathological modern humans.
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Ersoy A, Kelley J, Andrews P, Alpagut B. Hominoid phalanges from the middle Miocene site of Paşalar, Turkey. J Hum Evol 2008; 54:518-29. [DOI: 10.1016/j.jhevol.2007.08.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2007] [Accepted: 05/21/2007] [Indexed: 11/26/2022]
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Matarazzo S. Knuckle walking signal in the manual digits ofPan andGorilla. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2008; 135:27-33. [PMID: 17787000 DOI: 10.1002/ajpa.20701] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
This article examines the curvature of the manual proximal and middle phalanges of species belonging to Pan, Gorilla, Ateles, Macaca, Pongo, Hylobates, and Cebus to determine whether middle phalangeal curvature, when considered in conjunction with proximal phalangeal curvature, yields a locomotor signal. Prior studies have demonstrated the discriminatory power of proximal phalanges for separating suspensory species (including knuckle walkers) from pronograde quadrupedal species, but less emphasis has been placed on the distinguishing phalangeal characteristics of taxa within the suspensory category. This study demonstrates, first, that middle phalanges discriminate suspensory from nonsuspensory species, although not as cleanly as proximal phalanges. Finer discrimination of locomotor signals, including subtle differences among animals employing different modes of suspension, is possible through a comparison of the curvatures of the proximal phalanges and corresponding middle phalanges. Their relative curvature differs in quadrupeds, brachiators, and knuckle walkers. Knuckle walkers (Pan and Gorilla) have relatively little curvature of the middle phalanges coupled with marked curvature of the proximal phalanges, whereas brachiators (Ateles and Hylobates) display marked curvature of both proximal and middle phalanges, and pronograde quadrupeds (Cebus and Macaca) have relatively straight proximal and moderately curved middle phalanges. Quadrumanous climbers (Pongo) have a unique combination of traits, whereby curvature is high in both proximal and middle phalanges, but less so in the latter than the former. These differences, predictable on the basis of the biomechanical forces to which digits are subjected, may open a new venue for future research on the locomotor repertoire of prebipedal ancestors of hominins.
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Affiliation(s)
- Stacey Matarazzo
- Department of Anthropology, University of Massachusetts at Amherst, Amherst, MA 01003, USA.
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Mittra ES, Smith HF, Lemelin P, Jungers WL. Comparative morphometrics of the primate apical tuft. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2007; 134:449-59. [PMID: 17657781 DOI: 10.1002/ajpa.20687] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The relationship between the structure and function of the primate apical tuft is poorly understood. This study addresses several hypotheses about apical tuft morphology using a large modern primate comparative sample. Two indices of tuft size are employed: expansion and robusticity. First, comparisons of relative apical tuft size were drawn among extant nonhuman primate groups in terms of locomotion and phylogenetic category. Both of these factors appear to play a role in apical tuft size among nonhuman primates. Suspensory primates and all platyrrhines had the smallest apical tufts, while terrestrial quadrupeds and all strepsirrhines (regardless of locomotor category) had the largest tufts. Similarly, hypotheses regarding the apical tufts of hominins, especially the large tufts of Neandertals were addressed using a comparison of modern warm- and cold-adapted humans. The results showed that cold-adapted populations possessed smaller apical tufts than did warm-adapted groups. Therefore, the cold-adaptation hypothesis for Neandertal distal phalangeal morphology is not supported. Also, early modern and Early Upper Paleolithic humans had apical tufts that were significantly less expanded and less robust than those of Neandertals. The hypothesis that a large apical tuft serves as support for an expanded digital pulp is supported by radiographic analysis of modern humans in that a significant correlation was discovered between the width of the apical tuft and the width of the pulp. The implications of these findings for hypotheses about the association of apical tuft size and tool making in the hominin fossil record are discussed.
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Affiliation(s)
- Erik S Mittra
- Division of Nuclear Medicine, Stanford University, Stanford, CA 94305, USA.
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Richmond BG. Biomechanics of phalangeal curvature. J Hum Evol 2007; 53:678-90. [PMID: 17761213 DOI: 10.1016/j.jhevol.2007.05.011] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2006] [Revised: 04/13/2007] [Accepted: 05/13/2007] [Indexed: 11/19/2022]
Abstract
Phalangeal curvature has been widely cited in primate functional morphology and is one of the key traits in the ongoing debate about whether the locomotion of early hominins included a significant degree of arboreality. This study examines the biomechanics of phalangeal curvature using data on hand posture, muscle recruitment, and anatomical moment arms to develop a finite element (FE) model of a siamang manual proximal phalanx during suspensory grasping. Strain patterns from experiments on intact cadaver forelimbs validated the model. The strain distribution in the curved siamang phalanx FE model was compared to that in a mathematically straight rendition in order to test the hypotheses that curvature: 1) reduces strain and 2) results in lower bending strains but relatively higher compression. In the suspensory posture, joint reaction forces load the articular ends of the phalanx in compression and dorsally, while muscle forces acting through the flexor sheath pull the mid-shaft palmarly. These forces compress the phalanx dorsally and tense it palmarly, effectively bending it 'open.' Strains in the curved model were roughly half that of the straight model despite equivalent lengths, areas, mechanical properties, and loading conditions in the two models. The curved model also experienced a higher ratio of compressive to tensile strains. Curvature reduces strains during grasping hand postures because the curved bone is more closely aligned with the joint reaction forces. Therefore, phalangeal curvature reduces the strains associated with arboreal, and especially suspensory, activity involving flexed digits. These results offer a biomechanical explanation for the observed association between phalangeal curvature and arboreality.
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Affiliation(s)
- Brian G Richmond
- Center for the Advanced Study of Hominid Paleobiology, The George Washington University, Washington D.C. 20052, USA.
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Jungers WL, Lemelin P, Godfrey LR, Wunderlich RE, Burney DA, Simons EL, Chatrath PS, James HF, Randria GFN. The hands and feet of Archaeolemur: metrical affinities and their functional significance. J Hum Evol 2006; 49:36-55. [PMID: 15989943 DOI: 10.1016/j.jhevol.2005.03.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2004] [Revised: 03/03/2005] [Accepted: 03/03/2005] [Indexed: 10/25/2022]
Abstract
Recent expeditions to Madagascar have recovered abundant skeletal remains of Archaeolemur, one of the so-called "monkey lemurs" known from Holocene deposits scattered across the island. These new skeletons are sufficiently complete to permit reassembly of entire hands and feet--postcranial elements crucial to drawing inferences about substrate preferences and positional behavior. Univariate and multivariate analysis of intrinsic hand and foot proportions, phalangeal indices, relative pollex and hallux lengths, phalangeal curvature, and distal phalangeal shape reveal a highly derived and unique morphology for an extinct strepsirrhine that diverges dramatically from that of living lemurs and converges in some respects on that of Old World monkeys (e.g., mandrills, but not baboons or geladas). The hands and feet of Archaeolemur are relatively short (extremely so relative to body size); the carpus and tarsus are both "long" relative to total hand and foot lengths, respectively; phalangeal indices of both the hands and feet are low; both pollex and hallux are reduced; the apical tufts of the distal phalanges are very broad; and the proximal phalanges are slightly curved (but more so than in baboons). Overall grasping capabilities may have been compromised to some extent, and dexterous handling of small objects seems improbable. Deliberate and noncursorial quadrupedalism was most likely practiced on both the ground and in the trees. A flexible locomotor repertoire in conjunction with a eurytopic trophic adaptation allowed Archaeolemur to inhabit much of Madagascar and may explain why it was one of the latest surviving subfossil lemurs.
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Affiliation(s)
- W L Jungers
- Department of Anatomical Sciences, Stony Brook University, Stony Brook, NY 11794-8081, USA.
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Deane AS, Kremer EP, Begun DR. New approach to quantifying anatomical curvatures using high-resolution polynomial curve fitting (HR-PCF). AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2005; 128:630-8. [PMID: 15861424 DOI: 10.1002/ajpa.20202] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- A S Deane
- Department of Anthropology, University of Toronto, Toronto, Ontario M5S 3G3, Canada.
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Patel BA. Form and function of the oblique cord (chorda obliqua) in anthropoid primates. Primates 2004; 46:47-57. [PMID: 15241636 DOI: 10.1007/s10329-004-0094-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2003] [Accepted: 04/26/2004] [Indexed: 11/29/2022]
Abstract
The oblique cord of the forearm in humans is a ligament connecting the anterolateral aspect of the ulna proximally to the posteromedial aspect of the radius distally, inserting just below the radial tuberosity. Its functional significance is uncertain, but it has been proposed that the ligament limits supination of the forearm or aids in resisting buckling failure in the curved radius. These functional explanations are unsatisfactory for bipedal humans who do not use their forelimbs in weight support. Furthermore, there are no evolutionary explanations for its presence in humans. The purpose of this study was to investigate the distribution and form of the oblique cord in non-human primates and to explore its possible functional significance and evolutionary origin in humans. Soft tissue dissections of anthropoid primates revealed the presence of an oblique cord in New and Old World monkeys and Asian apes. It was absent in all atelines. Passive manipulation of the two forearm bones in all specimens revealed that the ligament becomes most taut in pronation contrary to the proposed human condition. Isolated radii show that the oblique cord's radial insertion lacks a clear relationship with bone curvature, thus providing little support for the hypothesis of preventing buckling failure. The oblique cord's involvement in reducing bending strain in the curved radius is also unlikely. It is suggested here that the ligament may have a role in maintaining elbow stability in quadrupedal primates. Therefore, the function of the oblique cord in anthropoid primates suggests that its presence in modern humans may be a morphological and functional remnant from a quadrupedal ancestry.
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Affiliation(s)
- Biren A Patel
- Interdepartmental Doctoral Program in Anthropological Sciences, Stony Brook University, SBS Building, Room S-501, Stony Brook, NY 11794-4364, USA.
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Abstract
Oreopithecus bambolii, an ape from the late Miocene of Italy, is said to possess a hand capable of a precision grip like that of humans. Relative hand length, proportions of the thumb, and morphological features of the thumb and wrist were adduced to support the idea that Oreopithecus had a hand that closely matched the pattern in Australopithecus. A reappraisal of earlier arguments and comparisons of Oreopithecus with humans, apes, and Old World monkeys, reveals that Oreopithecus had an essentially ape-like hand that emphasized ape-like power grasping over human-like precision grasping.
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Affiliation(s)
- Randall L Susman
- Department of Anatomical Sciences, School of Medicine, Stony Brook University, Stony Brook, NY 11794-8081, USA.
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Susman RL, de Ruiter D, Brain CK. Recently identified postcranial remains of Paranthropus and early Homo from Swartkrans Cave, South Africa. J Hum Evol 2001; 41:607-29. [PMID: 11782111 DOI: 10.1006/jhev.2001.0510] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Fifteen newly recognized hominid postcranials from Swartkrans are described here and compared with a sample of previously described early hominids, African apes and modern humans. Ten of the new specimens are from Member 1. Two are from Member 2 and three are from Member 3. Nine of the fossils are referred to Paranthropus, three to Homo, and three specimens cannot be assigned at present. The collection of hominid postcranials from Members 1-3 at Swartkrans now numbers more than 70 specimens. With the description of two new, small femoral heads, SKW 19 and SK 3121, there are now four proximal femora from Swartkrans. When SK 82 and SK 97 are compared with SKW 19 and SK 3121, the two sets offer important insights into body size and sexual dimorphism in Paranthropus robustus.A new distal femur, SK 1896 and other bones attributed to Homo cf. erectus, indicate that male Homo were larger than Paranthropus at Swartkrans.
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Affiliation(s)
- R L Susman
- Department of Anatomical Sciences, School of Medicine, University at Stony Brook, Stony Brook, New York 11794-8081, USA.
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46
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Marzke MW, Marzke RF. Evolution of the human hand: approaches to acquiring, analysing and interpreting the anatomical evidence. J Anat 2000; 197 ( Pt 1):121-40. [PMID: 10999274 PMCID: PMC1468111 DOI: 10.1046/j.1469-7580.2000.19710121.x] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The discovery of fossil hand bones from an early human ancestor at Olduvai Gorge in 1960, at the same level as primitive stone tools, generated a debate about the role of tools in the evolution of the human hand that has raged to the present day. Could the Olduvai hand have made the tools? Did the human hand evolve as an adaptation to tool making and tool use? The debate has been fueled by anatomical studies comparing living and fossil human and nonhuman primate hands, and by experimental observations. These have assessed the relative abilities of apes and humans to manufacture the Oldowan tools, but consensus has been hampered by disagreements about how to translate experimental data from living species into quantitative models for predicting the performance of fossil hands. Such models are now beginning to take shape as new techniques are applied to the capture, management and analysis of data on kinetic and kinematic variables ranging from hand joint structure, muscle mechanics, and the distribution and density of bone to joint movements and muscle recruitment during manipulative behaviour. The systematic comparative studies are highlighting a functional complex of features in the human hand facilitating a distinctive repertoire of grips that are apparently more effective for stone tool making than grips characterising various nonhuman primate species. The new techniques are identifying skeletal variables whose form may provide clues to the potential of fossil hominid hands for one-handed firm precision grips and fine precision manoeuvering movements, both of which are essential for habitual and effective tool making and tool use.
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Affiliation(s)
- M W Marzke
- Department of Anthropology, Arizona State University, Tempe 85287, USA
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Wrangham R, Jones J, Laden G, Pilbeam D, Conklin‐Brittain N. The Raw and the Stolen. CURRENT ANTHROPOLOGY 1999. [DOI: 10.1086/300083] [Citation(s) in RCA: 432] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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49
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50
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Jungers WL, Godfrey LR, Simons EL, Chatrath PS. Phalangeal curvature and positional behavior in extinct sloth lemurs (Primates, Palaeopropithecidae). Proc Natl Acad Sci U S A 1997; 94:11998-2001. [PMID: 11038588 PMCID: PMC23681 DOI: 10.1073/pnas.94.22.11998] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Recent paleontological discoveries in Madagascar document the existence of a diverse clade of palaeopropithecids or "sloth lemurs": Mesopropithecus (three species), Babakotia (one species), Palaeopropithecus (three species), and Archaeoindris (one species). This mini-radiation of now extinct ("subfossil") lemurs is most closely related to the living indrids (Indri, Propithecus, and Avahi). Whereas the extant indrids are known for their leaping acrobatics, the palaeopropithecids (except perhaps for the poorly known giant Archaeoindris) exhibit numerous skeletal design features for antipronograde or suspensory positional behaviors (e.g., high intermembral indices and mobile joints). Here we analyze the curvature of the proximal phalanges of the hands and feet. Computed as the included angle (theta), phalangeal curvature develops in response to mechanical use and is known to be correlated in primates with hand and foot function in different habitats; terrestrial species have straighter phalanges than their arboreal counterparts, and highly suspensory forms such as the orangutan possess the most curved phalanges. Sloth lemurs as a group are characterized by very curved proximal phalanges, exceeding those seen in spider monkeys and siamangs, and approaching that of orangutans. Indrids have curvatures roughly half that of sloth lemurs, and the more terrestrial, subfossil Archaeolemur possesses the least curved phalanges of all the indroids. Taken together with many other derived aspects of their postcranial anatomy, phalangeal curvature indicates that the sloth lemurs are one of the most suspensory clades of mammals ever to evolve.
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Affiliation(s)
- W L Jungers
- Department of Anatomical Sciences, School of Medicine, State University of New York, Stony Brook, NY 11794-8081, USA
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