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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. Am J Biol Anthropol 2024; 184:e24902. [PMID: 38400773 DOI: 10.1002/ajpa.24902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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Dunmore CJ, Bachmann S, Synek A, Pahr DH, Skinner MM, Kivell TL. The deep trabecular structure of first metacarpals in extant hominids. Am J Biol Anthropol 2024; 183:e24695. [PMID: 36790736 DOI: 10.1002/ajpa.24695] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 11/07/2022] [Accepted: 01/04/2023] [Indexed: 06/18/2023]
Abstract
OBJECTIVES Recent studies have associated subarticular trabecular bone distribution in the extant hominid first metacarpal (Mc1) with observed thumb use, to infer fossil hominin thumb use. Here, we analyze the entire Mc1 to test for interspecific differences in: (1) the absolute volume of trabecular volume fraction, (2) the distribution of the deeper trabecular network, and (3) the distribution of trabeculae in the medullary cavity, especially beneath the Mc1 disto-radial flange. MATERIALS AND METHODS Trabecular bone was imaged using micro-computed tomography in a sample of Homo sapiens (n = 11), Pan paniscus (n = 10), Pan troglodytes (n = 11), Gorilla gorilla (n = 10) and Pongo sp., (n = 7). Using Canonical Holistic Morphometric Analysis (cHMA), we tested for interspecific differences in the trabecular bone volume fraction (BV/TV) and its relative distribution (rBV/TV) throughout the Mc1, including within the head, medullary cavity, and base. RESULTS P. paniscus had the highest, and H. sapiens the lowest, BV/TV relative to other species. rBV/TV distribution statistically distinguished the radial concentrations and lack of medullary trabecular bone in the H. sapiens Mc1 from all other hominids. H. sapiens and, to a lesser extent, G. gorilla also had a significantly higher trabecular volume beneath the disto-radial flange relative to other hominids. DISCUSSION These results are consistent with differences in observed thumb use in these species and may also reflect systemic differences in bone volume fraction. The trabecular bone extension into the medullary cavity and concentrations beneath the disto-radial flange may represent crucial biomechanical signals that will aid in the inference of fossil hominin thumb use.
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Affiliation(s)
- Christopher J Dunmore
- Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, UK
| | - Sebastian Bachmann
- Institute of Lightweight Design and Structural Biomechanics, TU Wien, Vienna, Austria
| | - Alexander Synek
- Institute of Lightweight Design and Structural Biomechanics, TU Wien, Vienna, Austria
| | - Dieter H Pahr
- Institute of Lightweight Design and Structural Biomechanics, TU Wien, Vienna, Austria
- Department of Anatomy and Biomechanics, Division Biomechanics, Karl Landsteiner University of Health Sciences, Krems, Austria
| | - Matthew M Skinner
- Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, UK
- Centre for the Exploration of the Deep Human Journey, University of the Witwatersrand, Johannesburg, South Africa
| | - Tracy L Kivell
- Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, UK
- Centre for the Exploration of the Deep Human Journey, University of the Witwatersrand, Johannesburg, South Africa
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Bird EE, Kivell TL, Dunmore CJ, Tocheri MW, Skinner MM. Trabecular bone structure of the proximal capitate in extant hominids and fossil hominins with implications for midcarpal joint loading and the dart-thrower's motion. Am J Biol Anthropol 2024; 183:e24824. [PMID: 37493308 DOI: 10.1002/ajpa.24824] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 05/05/2023] [Accepted: 07/10/2023] [Indexed: 07/27/2023]
Abstract
OBJECTIVES This research examines whether the distribution of trabecular bone in the proximal capitates of extant hominids, as well as several fossil hominin taxa, is associated with the oblique path of the midcarpal joint known as the dart-thrower's motion (DTM). MATERIALS AND METHODS We analyzed proximal capitates from extant (Pongo n = 12; Gorilla n = 11; Pan n = 10; fossil and recent Homo sapiens n = 29) and extinct (Australopithecus sediba n = 2; Homo naledi n = 1; Homo floresiensis n = 2; Neandertals n = 3) hominids using a new canonical holistic morphometric analysis, which quantifies and visualizes the distribution of trabecular bone using relative bone volume as a fraction of total volume (rBV/TV). RESULTS Homo sapiens and Neandertals had a continuous band of high rBV/TV that extended across the scaphoid, lunate, and hamate subarticular regions, but other fossil hominins and extant great apes did not. A. sediba expressed a distinct combination of human-like and Pan-like rBV/TV distribution. Both H. floresiensis and H. naledi had high rBV/TV on the ulnar-side of the capitate but low rBV/TV on the radial-side. CONCLUSION The proximal capitates of H. sapiens and Neandertals share a distinctive distribution of trabecular bone that suggests that these two species of Homo regularly load(ed) their midcarpal joints along the full extent of the oblique path of the DTM. The observed pattern in A. sediba suggests that human-like stress at the capito-scaphoid articular surface was combined with Pan-like wrist postures, whereas the patterns in H. floresiensis and H. naledi suggest their midcarpal joints were loaded differently from that of H. sapiens and Neandertals.
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Affiliation(s)
- Emma E Bird
- Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, UK
- Centre for Human Evolution Research, Natural History Museum, London, UK
| | - Tracy L Kivell
- Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, UK
- Centre for the Exploration of the Deep Human Journey, University of the Witwatersrand, Johannesburg, South Africa
| | - Christopher J Dunmore
- Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, UK
| | - Matthew W Tocheri
- Department of Anthropology, Lakehead University, Thunder Bay, Ontario, Canada
- Human Origins Program, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA
- Australian Research Council, Centre of Excellence for Australian Biodiversity and Heritage, University of Wollongong, Wollongong, New South Wales, Australia
| | - Matthew M Skinner
- Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, UK
- Centre for the Exploration of the Deep Human Journey, University of the Witwatersrand, Johannesburg, South Africa
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Bardo A, Dunmore CJ, Cornette R, Kivell TL. Morphological integration and shape covariation between the trapezium and first metacarpal among extant hominids. Am J Biol Anthropol 2024; 183:e24800. [PMID: 37377134 DOI: 10.1002/ajpa.24800] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2022] [Revised: 04/16/2023] [Accepted: 06/04/2023] [Indexed: 06/29/2023]
Abstract
OBJECTIVES The shape of the trapezium and first metacarpal (Mc1) markedly influence thumb mobility, strength, and the manual abilities of extant hominids. Previous research has typically focused solely on trapezium-Mc1 joint shape. Here we investigate how morphological integration and shape covariation between the entire trapezium (articular and non-articular surfaces) and the entire Mc1 reflect known differences in thumb use in extant hominids. MATERIALS AND METHODS We analyzed shape covariation in associated trapezia and Mc1s across a large, diverse sample of Homo sapiens (n = 40 individuals) and other extant hominids (Pan troglodytes, n = 16; Pan paniscus, n = 13; Gorilla gorilla gorilla, n = 27; Gorilla beringei, n = 6; Pongo pygmaeus, n = 14; Pongo abelii, n = 9) using a 3D geometric morphometric approach. We tested for interspecific significant differences in degree of morphological integration and patterns of shape covariation between the entire trapezium and Mc1, as well as within the trapezium-Mc1 joint specifically. RESULTS Significant morphological integration was only found in the trapezium-Mc1 joint of H. sapiens and G. g. gorilla. Each genus showed a specific pattern of shape covariation between the entire trapezium and Mc1 that was consistent with different intercarpal and carpometacarpal joint postures. DISCUSSION Our results are consistent with known differences in habitual thumb use, including a more abducted thumb during forceful precision grips in H. sapiens and a more adducted thumb in other hominids used for diverse grips. These results will help to infer thumb use in fossil hominins.
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Affiliation(s)
- Ameline Bardo
- Département Homme et Environnement, UMR 7194 - HNHP, CNRS-MNHN, Musée de l'Homme, Paris, France
- Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, Kent, UK
| | - Christopher J Dunmore
- Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, Kent, UK
| | - Raphaël Cornette
- Institute of Systematic, Evolution, Biodiversity (ISYEB), UMR 7205-CNRS/MNHN/UPMC/EPHE, National Museum of Natural History, Paris, France
| | - Tracy L Kivell
- Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, Kent, UK
- Department of Human Origins, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
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Orr CM, Kivell TL, Tocheri MW. Mary Marzke, PhD: A pioneer and innovator in the study of the evolution of the human hand. Am J Biol Anthropol 2024; 183:e24892. [PMID: 38263793 DOI: 10.1002/ajpa.24892] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Accepted: 12/13/2023] [Indexed: 01/25/2024]
Affiliation(s)
- Caley M Orr
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, Colorado, USA
- Department of Anthropology, University of Colorado Denver, Denver, Colorado, USA
| | - Tracy L Kivell
- Department of Anthropology and Conservation, University of Kent, Canterbury, UK
- Department of Human Origins, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Matthew W Tocheri
- Department of Anthropology, Lakehead University, Thunder Bay, Ontario, Canada
- Human Origins Program, Department of Anthropology, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA
- Australian Research Council Centre of Excellence for Australian Biodiversity and Heritage, University of Wollongong, Wollongong, Australia
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Lukova A, Dunmore CJ, Bachmann S, Synek A, Pahr DH, Kivell TL, Skinner MM. Trabecular architecture of the distal femur in extant hominids. J Anat 2024. [PMID: 38381116 DOI: 10.1111/joa.14026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 02/01/2024] [Accepted: 02/05/2024] [Indexed: 02/22/2024] Open
Abstract
Extant great apes are characterized by a wide range of locomotor, postural and manipulative behaviours that each require the limbs to be used in different ways. In addition to external bone morphology, comparative investigation of trabecular bone, which (re-)models to reflect loads incurred during life, can provide novel insights into bone functional adaptation. Here, we use canonical holistic morphometric analysis (cHMA) to analyse the trabecular morphology in the distal femoral epiphysis of Homo sapiens (n = 26), Gorilla gorilla (n = 14), Pan troglodytes (n = 15) and Pongo sp. (n = 9). We test two predictions: (1) that differing locomotor behaviours will be reflected in differing trabecular architecture of the distal femur across Homo, Pan, Gorilla and Pongo; (2) that trabecular architecture will significantly differ between male and female Gorilla due to their different levels of arboreality but not between male and female Pan or Homo based on previous studies of locomotor behaviours. Results indicate that trabecular architecture differs among extant great apes based on their locomotor repertoires. The relative bone volume and degree of anisotropy patterns found reflect habitual use of extended knee postures during bipedalism in Homo, and habitual use of flexed knee posture during terrestrial and arboreal locomotion in Pan and Gorilla. Trabecular architecture in Pongo is consistent with a highly mobile knee joint that may vary in posture from extension to full flexion. Within Gorilla, trabecular architecture suggests a different loading of knee in extension/flexion between females and males, but no sex differences were found in Pan or Homo, supporting our predictions. Inter- and intra-specific variation in trabecular architecture of distal femur provides a comparative context to interpret knee postures and, in turn, locomotor behaviours in fossil hominins.
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Affiliation(s)
- Andrea Lukova
- Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, UK
| | - Christopher J Dunmore
- Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, UK
| | - Sebastian Bachmann
- Institute of Lightweight Design and Structural Biomechanics, TU Wien, Wien, Austria
| | - Alexander Synek
- Institute of Lightweight Design and Structural Biomechanics, TU Wien, Wien, Austria
| | - Dieter H Pahr
- Institute of Lightweight Design and Structural Biomechanics, TU Wien, Wien, Austria
- Department of Anatomy and Biomechanics, Division Biomechanics, Karl Landsteiner University of Health Sciences, Krems, Austria
| | - Tracy L Kivell
- Department of Human Origins, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Matthew M Skinner
- Department of Human Origins, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
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Tanner SB, Bardo A, Davies TW, Dunmore CJ, Johnston RE, Owen NJ, Kivell TL, Skinner MM. Variation and covariation of external shape and cross-sectional geometry in the human metacarpus. Am J Biol Anthropol 2024; 183:e24866. [PMID: 37929663 PMCID: PMC10952563 DOI: 10.1002/ajpa.24866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 09/05/2023] [Accepted: 10/10/2023] [Indexed: 11/07/2023]
Abstract
OBJECTIVES Analyses of external bone shape using geometric morphometrics (GM) and cross-sectional geometry (CSG) are frequently employed to investigate bone structural variation and reconstruct activity in the past. However, the association between these methods has not been thoroughly investigated. Here, we analyze whole bone shape and CSG variation of metacarpals 1-5 and test covariation between them. MATERIALS AND METHODS We analyzed external metacarpal shape using GM and CSG of the diaphysis at three locations in metacarpals 1-5. The study sample includes three modern human groups: crew from the shipwrecked Mary Rose (n = 35 metacarpals), a Pre-industrial group (n = 50), and a Post-industrial group (n = 31). We tested group differences in metacarpal shape and CSG, as well as correlations between these two aspects of metacarpal bone structure. RESULTS GM analysis demonstrated metacarpus external shape variation is predominately related to changes in diaphyseal width and articular surface size. Differences in external shape were found between the non-pollical metacarpals of the Mary Rose and Pre-industrial groups and between the third metacarpals of the Pre- and Post-industrial groups. CSG results suggest the Mary Rose and Post-industrial groups have stronger metacarpals than the Pre-industrial group. Correlating CSG and external shape showed significant relationships between increasing external robusticity and biomechanical strength across non-pollical metacarpals (r: 0.815-0.535; p ≤ 0.05). DISCUSSION Differences in metacarpal cortical structure and external shape between human groups suggest differences in the type and frequency of manual activities. Combining these results with studies of entheses and kinematics of the hand will improve reconstructions of manual behavior in the past.
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Affiliation(s)
- Samuel B. Tanner
- School of Anthropology and ConservationUniversity of KentCanterburyUK
| | - Ameline Bardo
- School of Anthropology and ConservationUniversity of KentCanterburyUK
- UMR 7194 ‐ Histoire Naturelle de l'Homme Préhistorique (HNHP)CNRS‐Muséum National d'Histoire NaturelleParisFrance
| | - Thomas W. Davies
- School of Anthropology and ConservationUniversity of KentCanterburyUK
- Department of Human OriginsMax Planck Institute for Evolutionary AnthropologyLeipzigGermany
| | | | - Richard E. Johnston
- Advanced Imaging of Materials (AIM) Facility, Faculty of Science and Engineering, Bay CampusSwansea UniversitySwanseaUK
| | - Nicholas J. Owen
- Applied Sports Technology Exercise and Medicine Research Centre (A‐STEM), School of Engineering and Applied Sciences, Bay CampusSwansea UniversitySwanseaUK
| | - Tracy L. Kivell
- School of Anthropology and ConservationUniversity of KentCanterburyUK
- Department of Human OriginsMax Planck Institute for Evolutionary AnthropologyLeipzigGermany
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Cazenave M, Kivell TL. Challenges and perspectives on functional interpretations of australopith postcrania and the reconstruction of hominin locomotion. J Hum Evol 2023; 175:103304. [PMID: 36563461 DOI: 10.1016/j.jhevol.2022.103304] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 11/15/2022] [Accepted: 11/16/2022] [Indexed: 12/24/2022]
Abstract
In 1994, Hunt published the 'postural feeding hypothesis'-a seminal paper on the origins of hominin bipedalism-founded on the detailed study of chimpanzee positional behavior and the functional inferences derived from the upper and lower limb morphology of the Australopithecus afarensis A.L. 288-1 partial skeleton. Hunt proposed a model for understanding the potential selective pressures on hominins, made robust, testable predictions based on Au. afarensis functional morphology, and presented a hypothesis that aimed to explain the dual functional signals of the Au. afarensis and, more generally, early hominin postcranium. Here we synthesize what we have learned about Au. afarensis functional morphology and the dual functional signals of two new australopith discoveries with relatively complete skeletons (Australopithecus sediba and StW 573 'Australopithecus prometheus'). We follow this with a discussion of three research approaches that have been developed for the purpose of drawing behavioral inferences in early hominins: (1) developments in the study of extant apes as models for understanding hominin origins; (2) novel and continued developments to quantify bipedal gait and locomotor economy in extant primates to infer the locomotor costs from the anatomy of fossil taxa; and (3) novel developments in the study of internal bone structure to extract functional signals from fossil remains. In conclusion of this review, we discuss some of the inherent challenges of the approaches and methodologies adopted to reconstruct the locomotor modes and behavioral repertoires in extinct primate taxa, and notably the assessment of habitual terrestrial bipedalism in early hominins.
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Affiliation(s)
- Marine Cazenave
- Division of Anthropology, American Museum of Natural History, New York, USA; Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, UK; Department of Anatomy, Faculty of Health Sciences, University of Pretoria, South Africa.
| | - Tracy L Kivell
- Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, UK; Centre for the Exploration of the Deep Human Journey, University of the Witwatersrand, Johannesburg, South Africa
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Drummond-Clarke RC, Kivell TL, Sarringhaus L, Stewart FA, Humle T, Piel AK. Wild chimpanzee behavior suggests that a savanna-mosaic habitat did not support the emergence of hominin terrestrial bipedalism. Sci Adv 2022; 8:eadd9752. [PMID: 36516260 PMCID: PMC9750136 DOI: 10.1126/sciadv.add9752] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/16/2022] [Accepted: 11/08/2022] [Indexed: 06/17/2023]
Abstract
Bipedalism, a defining feature of the human lineage, is thought to have evolved as forests retreated in the late Miocene-Pliocene. Chimpanzees living in analogous habitats to early hominins offer a unique opportunity to investigate the ecological drivers of bipedalism that cannot be addressed via the fossil record alone. We investigated positional behavior and terrestriality in a savanna-mosaic community of chimpanzees (Pan troglodytes schweinfurthii) in the Issa Valley, Tanzania as the first test in a living ape of the hypothesis that wooded, savanna habitats were a catalyst for terrestrial bipedalism. Contrary to widely accepted hypotheses of increased terrestriality selecting for habitual bipedalism, results indicate that trees remained an essential component of the hominin adaptive niche, with bipedalism evolving in an arboreal context, likely driven by foraging strategy.
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Affiliation(s)
| | - Tracy L. Kivell
- School of Anthropology and Conservation, University of Kent, Canterbury, UK
- Centre for the Exploration of the Deep Human Journey, University of the Witwatersrand, Johannesburg, South Africa
| | - Lauren Sarringhaus
- Department of Evolutionary Anthropology, Duke University, Durham, NC, USA
- Department of Anthropology, University of Michigan, Ann Arbor, MI, USA
| | - Fiona A. Stewart
- Department of Anthropology, University College London, London, UK
- School of Biological and Environmental Sciences, Liverpool John Moores University, Liverpool, UK
| | - Tatyana Humle
- School of Anthropology and Conservation, University of Kent, Canterbury, UK
| | - Alex K. Piel
- Department of Anthropology, University College London, London, UK
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Bird EE, Kivell TL, Skinner MM. Patterns of internal bone structure and functional adaptation in the hominoid scaphoid, lunate, and triquetrum. American J Phys Anthropol 2021. [DOI: 10.1002/ajpa.24449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Emma E. Bird
- Skeletal Biology Research Centre, School of Anthropology and Conservation University of Kent Canterbury UK
| | - Tracy L. Kivell
- Skeletal Biology Research Centre, School of Anthropology and Conservation University of Kent Canterbury 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 UK
- Department of Human Evolution Max Planck Institute for Evolutionary Anthropology Leipzig Germany
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13
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Arias-Martorell J, Zeininger A, Kivell TL. Trabecular structure of the elbow reveals divergence in knuckle-walking biomechanical strategies of African apes. Evolution 2021; 75:2959-2971. [PMID: 34570906 DOI: 10.1111/evo.14354] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 07/29/2021] [Accepted: 08/03/2021] [Indexed: 01/04/2023]
Abstract
African apes engage in a distinct form of locomotion called knuckle-walking, but there is much ambiguity as to when and how this locomotor behavior evolved. This study aims to elucidate potential differences in knuckle-walking elbow posture and loading in African apes through the study of trabecular bone. Using a whole-epiphysis approach, we quantified variation in the trabecular structure of the distal humerus of chimpanzees, western lowland gorillas, and mountain gorillas in comparison to orang-utans, siamangs, and a sample of Old and New World monkeys. Results demonstrate differences in the distribution of trabecular bone within the distal humerus that are consistent across taxa that habitually use a flexed-elbow posture in comparison to those that use an extended elbow during locomotion. Western lowland gorillas show an extended-elbow pattern consistent with the straight forelimb position during knuckle-walking, whereas chimpanzees show a flexed-elbow pattern. Unexpectedly, mountain gorillas show an intermediate pattern between their western counterparts and chimpanzees. The differences found in elbow joint posture between chimpanzees and gorillas, and between gorilla species, point to diversification in the knuckle-walking biomechanical strategies among African apes, which has implications in the debate regarding the locomotor behavior from which human bipedalism arose.
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Affiliation(s)
- Julia Arias-Martorell
- Institut Català de Paleontologia Miquel Crusafont, Edifici ICTA-ICP, Carrer Columnes s/n, Campus de la UAB, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain.,Animal Postcranial Evolution (APE) Laboratory, School of Anthropology and Conservation, Marlowe Building, University of Kent, Canterbury, UK
| | - Angel Zeininger
- Department of Evolutionary Anthropology, Duke University, Durham, North Carolina, USA
| | - Tracy L Kivell
- Animal Postcranial Evolution (APE) Laboratory, School of Anthropology and Conservation, Marlowe Building, University of Kent, Canterbury, UK.,Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
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14
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Bowland LA, Scott JE, Kivell TL, Patel BA, Tocheri MW, Orr CM. Homo naledi pollical metacarpal shaft morphology is distinctive and intermediate between that of australopiths and other members of the genus Homo. J Hum Evol 2021; 158:103048. [PMID: 34340120 DOI: 10.1016/j.jhevol.2021.103048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 06/25/2021] [Accepted: 06/26/2021] [Indexed: 10/20/2022]
Abstract
Homo naledi fossils from the Rising Star cave system provide important insights into the diversity of hand morphology within the genus Homo. Notably, the pollical (thumb) metacarpal (Mc1) displays an unusual suite of characteristics including a median longitudinal crest, a narrow proximal base, and broad flaring intrinsic muscle flanges. The present study evaluates the affinities of H. naledi Mc1 morphology via 3D geometric morphometric analysis of shaft shape using a broader comparative sample (n = 337) of fossil hominins, recent humans, apes, and cercopithecoid monkeys than in prior work. Results confirm that the H. naledi Mc1 is distinctive from most other hominins in being narrow at the proximal end but surmounted by flaring muscle flanges distally. Only StW 418 (Australopithecus cf. africanus) is similar in these aspects of shape. The gracile proximal shaft is most similar to cercopithecoids, Pan, Pongo, Australopithecus afarensis, and Australopithecus sediba, suggesting that H. naledi retains the condition primitive for the genus Homo. In contrast, Neandertal Mc1s are characterized by wide proximal bases and shafts, pinched midshafts, and broad distal flanges, while those of recent humans generally have straight shafts, less robust muscle flanges, and wide proximal shafts/bases. Although uncertainties remain regarding character polarity, the morphology of the H. naledi thumb might be interpreted as a retained intermediate state in a transformation series between the overall gracility of the shaft and the robust shafts of later hominins. Such a model suggests that the addition of broad medial and lateral muscle flanges to a primitively slender shaft was the first modification in transforming the Mc1 into the overall more robust structure exhibited by other Homo taxa including Neandertals and recent Homo sapiens in whose shared lineage the bases and proximal shafts became expanded, possibly as an adaptation to the repeated recruitment of powerful intrinsic pollical muscles.
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Affiliation(s)
- Lucyna A Bowland
- Department of Anthropology, University of Arkansas, Fayetteville, AR, 72701, USA
| | - Jill E Scott
- Department of Sociology and Anthropology, Metropolitan State University of Denver, Denver, CO, 80217, USA; Centre for the Exploration of the Deep Human Journey, University of the Witwatersrand, WITS 2050, Johannesburg, South Africa
| | - Tracy L Kivell
- Centre for the Exploration of the Deep Human Journey, University of the Witwatersrand, WITS 2050, Johannesburg, South Africa; School of Anthropology and Conservation, University of Kent, Canterbury, CT2 7NR, UK; Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, 04103, Germany
| | - 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
| | - Matthew W Tocheri
- Department of Anthropology, Lakehead University, Thunder Bay, ON, P7K 1L8, Canada; Human Origins Program, Department of Anthropology, National Museum of Natural History, Smithsonian Institution, Washington DC, 20560, USA; Australian Research Council Centre of Excellence for Australian Biodiversity and Heritage, University of Wollongong, Wollongong, New South Wales, 2522, Australia
| | - 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.
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15
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Bird EE, Kivell TL, Skinner MM. Cortical and trabecular bone structure of the hominoid capitate. J Anat 2021; 239:351-373. [PMID: 33942895 PMCID: PMC8273598 DOI: 10.1111/joa.13437] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 03/16/2021] [Accepted: 03/17/2021] [Indexed: 01/02/2023] Open
Abstract
Morphological variation in the hominoid capitate has been linked to differences in habitual locomotor activity due to its importance in movement and load transfer at the midcarpal joint proximally and carpometacarpal joints distally. Although the shape of bones and their articulations are linked to joint mobility, the internal structure of bones has been shown experimentally to reflect, at least in part, the loading direction and magnitude experienced by the bone. To date, it is uncertain whether locomotor differences among hominoids are reflected in the bone microarchitecture of the capitate. Here, we apply a whole‐bone methodology to quantify the cortical and trabecular architecture (separately and combined) of the capitate across bipedal (modern Homo sapiens), knuckle‐walking (Pan paniscus, Pan troglodytes, Gorilla sp.), and suspensory (Pongo sp.) hominoids (n = 69). It is hypothesized that variation in bone microarchitecture will differentiate these locomotor groups, reflecting differences in habitual postures and presumed loading force and direction. Additionally, it is hypothesized that trabecular and cortical architecture in the proximal and distal regions, as a result of being part of mechanically divergent joints proximally and distally, will differ across these portions of the capitate. Results indicate that the capitate of knuckle‐walking and suspensory hominoids is differentiated from bipedal Homo primarily by significantly thicker distal cortical bone. Knuckle‐walking taxa are further differentiated from suspensory and bipedal taxa by more isotropic trabeculae in the proximal capitate. An allometric analysis indicates that size is not a significant determinate of bone variation across hominoids, although sexual dimorphism may influence some parameters within Gorilla. Results suggest that internal trabecular and cortical bone is subjected to different forces and functional adaptation responses across the capitate (and possibly other short bones). Additionally, while separating trabecular and cortical bone is normal protocol of current whole‐bone methodologies, this study shows that when applied to carpals, removing or studying the cortical bone separately potentially obfuscates functionally relevant signals in bone structure.
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Affiliation(s)
- Emma E Bird
- Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, UK
| | - Tracy L Kivell
- Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, 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, UK.,Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
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16
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Kivell TL. Human evolution: Thumbs up for efficiency. Curr Biol 2021; 31:R289-R291. [PMID: 33756140 DOI: 10.1016/j.cub.2021.02.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Modelling a muscle key to flexing the thumb, a new study suggests that the powerful opposability that characterises the dextrous human hand evolved in some of our fossil relatives about two million years ago - a time when tool use became more important.
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Affiliation(s)
- Tracy L Kivell
- School of Anthropology and Conservation, University of Kent, Marlowe Building, Canterbury, Kent CT2 7NR, UK; Department of Human Evolution, Max-Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103 Leipzig, Germany; Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa.
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17
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Williams-Hatala EM, Hatala KG, Key A, Dunmore CJ, Kasper M, Gordon M, Kivell TL. Kinetics of stone tool production among novice and expert tool makers. Am J Phys Anthropol 2020; 174:714-727. [PMID: 33107044 DOI: 10.1002/ajpa.24159] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 08/21/2020] [Accepted: 09/15/2020] [Indexed: 12/30/2022]
Abstract
OBJECTIVES As is the case among many complex motor tasks that require prolonged practice before achieving expertise, aspects of the biomechanics of knapping vary according to the relative experience/skill level of the practitioner. In archaeological experiments focused on the production of Plio-Pleistocene stone tools, these skill-mediated biomechanical differences have bearings on experimental design, the interpretation of results, and lithic assemblage analysis. A robust body of work exists on variation in kinematic patterns across skill levels but less is known about potential kinetic differences. The current study was undertaken to better understand kinetic patterns observed across skill levels during "Oldowan," freehand stone tool production. MATERIALS AND METHODS Manual pressure data were collected from 23 novice and 9 expert stone tool makers during the production of simple stone flakes using direct hard hammer percussion. RESULTS Results show that expert tool makers experienced significantly lower cumulative pressure magnitudes and pressure-time integral magnitudes compared with novices. In expert knappers, digits I and II experienced similarly high pressures (both peak pressure and pressure-time integrals) and low variability in pressure relative to digits III-V. Novices, in contrast, tended to hold hammerstones such that pressure patterns were similar across digits II-V, and they showed low variability on digit I only. DISCUSSION The similar and consistent emphasis of the thumb by both skill groups indicates the importance of this digit in stabilizing the hammerstone. The emphasis placed on digit II is exclusive to expert knappers, and so this digit may offer osteological signals diagnostic of habitual expert tool production.
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Affiliation(s)
- Erin Marie Williams-Hatala
- Department of Biology, Chatham University, Pittsburgh, Pennsylvania, USA.,Center for the Advanced Study of Human Paleobiology, The George Washington University, Washington, District of Columbia, USA
| | - Kevin G Hatala
- Department of Biology, Chatham University, Pittsburgh, Pennsylvania, USA.,Center for the Advanced Study of Human Paleobiology, The George Washington University, Washington, District of Columbia, USA
| | - Alastair Key
- Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, UK
| | - Christopher J Dunmore
- Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, UK
| | - Margaret Kasper
- Department of Biology, Chatham University, Pittsburgh, Pennsylvania, USA
| | - McKenzie Gordon
- Department of Biology, Chatham University, Pittsburgh, Pennsylvania, USA
| | - Tracy L Kivell
- Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, UK.,Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
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18
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Dunmore CJ, Skinner MM, Bardo A, Berger LR, Hublin JJ, Pahr DH, Rosas A, Stephens NB, Kivell TL. The position of Australopithecus sediba within fossil hominin hand use diversity. Nat Ecol Evol 2020; 4:911-918. [PMID: 32424278 DOI: 10.1038/s41559-020-1207-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 04/15/2020] [Indexed: 11/09/2022]
Abstract
The human lineage is marked by a transition in hand use, from locomotion towards increasingly dexterous manipulation, concomitant with bipedalism. The forceful precision grips used by modern humans probably evolved in the context of tool manufacture and use, but when and how many times hominin hands became principally manipulative remains unresolved. We analyse metacarpal trabecular and cortical bone, which provide insight into behaviour during an individual's life, to demonstrate previously unrecognized diversity in hominin hand use. The metacarpals of the palm in Australopithecus sediba have trabecular morphology most like orangutans and consistent with locomotor power-grasping with the fingers, while that of the thumb is consistent with human-like manipulation. This internal morphology is the first record of behaviour consistent with a hominin that used its hand for both arboreal locomotion and human-like manipulation. This hand use is distinct from other fossil hominins in this study, including A. afarensis and A. africanus.
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Affiliation(s)
- Christopher J Dunmore
- Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, UK.
| | - Matthew M Skinner
- Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, UK.,Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.,Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa
| | - Ameline Bardo
- Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, UK
| | - Lee R Berger
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa
| | - Jean-Jacques Hublin
- Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.,Chaire Internationale de Paléoanthropologie, Collège de France, Paris, France
| | - Dieter H Pahr
- TU Wien Institute of Lightweight Design and Structural Biomechanics, Vienna, Austria
| | - Antonio Rosas
- Department of Paleobiology, National Museum of Natural Sciences, CSIC, Madrid, Spain
| | - Nicholas B Stephens
- Department of Anthropology, The Pennsylvania State University, State College, PA, USA
| | - Tracy L Kivell
- Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, UK.,Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.,Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa
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19
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Synek A, Lu SC, Nauwelaerts S, Pahr DH, Kivell TL. Metacarpophalangeal joint loads during bonobo locomotion: model predictions versus proxies. J R Soc Interface 2020; 17:20200032. [PMID: 32126191 DOI: 10.1098/rsif.2020.0032] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The analysis of internal trabecular and cortical bone has been an informative tool for drawing inferences about behaviour in extant and fossil primate taxa. Within the hand, metacarpal bone architecture has been shown to correlate well with primate locomotion; however, the extent of morphological differences across taxa is unexpectedly small given the variability in hand use. One explanation for this observation is that the activity-related differences in the joint loads acting on the bone are simply smaller than estimated based on commonly used proxies (i.e. external loading and joint posture), which neglect the influence of muscle forces. In this study, experimental data and a musculoskeletal finger model are used to test this hypothesis by comparing differences between climbing and knuckle-walking locomotion of captive bonobos (Pan paniscus) based on (i) joint load magnitude and direction predicted by the models and (ii) proxy estimations. The results showed that the activity-related differences in predicted joint loads are indeed much smaller than the proxies would suggest, with joint load magnitudes being almost identical between the two locomotor modes. Differences in joint load directions were smaller but still evident, indicating that joint load directions might be a more robust indicator of variation in hand use than joint load magnitudes. Overall, this study emphasizes the importance of including muscular forces in the interpretation of skeletal remains and promotes the use of musculoskeletal models for correct functional interpretations.
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Affiliation(s)
- Alexander Synek
- Institute of Lightweight Design and Structural Biomechanics, TU Wien, Vienna, Austria
| | - Szu-Ching Lu
- Animal Postcranial Evolution Laboratory, Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, UK.,Laboratory for Innovation in Autism, School of Education, University of Strathclyde, Glasgow, UK
| | - Sandra Nauwelaerts
- Department of Biology, University of Antwerp, Wilrijk, Belgium.,Center for Research and Conservation KMDA, Astridplein, Antwerpen, Belgium
| | - Dieter H Pahr
- Institute of Lightweight Design and Structural Biomechanics, TU Wien, Vienna, Austria.,Department of Anatomy and Biomechanics, Karl Landsteiner Private University of Health Sciences, Krems an der Donau, Austria
| | - Tracy L Kivell
- Animal Postcranial Evolution Laboratory, Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, UK.,Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
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20
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Dunmore CJ, Bardo A, Skinner MM, Kivell TL. Trabecular variation in the first metacarpal and manipulation in hominids. Am J Phys Anthropol 2019; 171:219-241. [PMID: 31762017 DOI: 10.1002/ajpa.23974] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 10/27/2019] [Accepted: 10/29/2019] [Indexed: 12/14/2022]
Abstract
OBJECTIVES The dexterity of fossil hominins is often inferred by assessing the comparative manual anatomy and behaviors of extant hominids, with a focus on the thumb. The aim of this study is to test whether trabecular structure is consistent with what is currently known about habitually loaded thumb postures across extant hominids. MATERIALS AND METHODS We analyze first metacarpal (Mc1) subarticular trabecular architecture in humans (Homo sapiens, n = 10), bonobos (Pan paniscus, n = 10), chimpanzees (Pan troglodytes, n = 11), as well as for the first time, gorillas (Gorilla gorilla gorilla, n = 10) and orangutans (Pongo sp., n = 1, Pongo abelii, n = 3 and Pongo pygmaeus, n = 5). Using a combination of subarticular and whole-epiphysis approaches, we test for significant differences in relative trabecular bone volume (RBV/TV) and degree of anisotropy (DA) between species. RESULTS Humans have significantly greater RBV/TV on the radiopalmar aspects of both the proximal and distal Mc1 subarticular surfaces and greater DA throughout the Mc1 head than other hominids. Nonhuman great apes have greatest RBV/TV on the ulnar aspect of the Mc1 head and the palmar aspect of the Mc1 base. Gorillas possessed significantly lower DA in the Mc1 head than any other taxon in our sample. DISCUSSION These results are consistent with abduction of the thumb during forceful "pad-to-pad" precision grips in humans and, in nonhuman great apes, a habitually adducted thumb that is typically used in precision and power grips. This comparative context will help infer habitual manipulative and locomotor grips in fossil hominins.
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Affiliation(s)
- Christopher J Dunmore
- Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, UK
| | - Ameline Bardo
- Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, UK
| | - Matthew M Skinner
- Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, UK.,Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Tracy L Kivell
- Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, UK.,Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
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21
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Synek A, Lu SC, Vereecke EE, Nauwelaerts S, Kivell TL, Pahr DH. Musculoskeletal models of a human and bonobo finger: parameter identification and comparison to in vitro experiments. PeerJ 2019; 7:e7470. [PMID: 31413932 PMCID: PMC6690335 DOI: 10.7717/peerj.7470] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Accepted: 07/15/2019] [Indexed: 02/06/2023] Open
Abstract
Introduction Knowledge of internal finger loading during human and non-human primate activities such as tool use or knuckle-walking has become increasingly important to reconstruct the behaviour of fossil hominins based on bone morphology. Musculoskeletal models have proven useful for predicting these internal loads during human activities, but load predictions for non-human primate activities are missing due to a lack of suitable finger models. The main goal of this study was to implement both a human and a representative non-human primate finger model to facilitate comparative studies on metacarpal bone loading. To ensure that the model predictions are sufficiently accurate, the specific goals were: (1) to identify species-specific model parameters based on in vitro measured fingertip forces resulting from single tendon loading and (2) to evaluate the model accuracy of predicted fingertip forces and net metacarpal bone loading in a different loading scenario. Materials & Methods Three human and one bonobo (Pan paniscus) fingers were tested in vitro using a previously developed experimental setup. The cadaveric fingers were positioned in four static postures and load was applied by attaching weights to the tendons of the finger muscles. For parameter identification, fingertip forces were measured by loading each tendon individually in each posture. For the evaluation of model accuracy, the extrinsic flexor muscles were loaded simultaneously and both the fingertip force and net metacarpal bone force were measured. The finger models were implemented using custom Python scripts. Initial parameters were taken from literature for the human model and own dissection data for the bonobo model. Optimized model parameters were identified by minimizing the error between predicted and experimentally measured fingertip forces. Fingertip forces and net metacarpal bone loading in the combined loading scenario were predicted using the optimized models and the remaining error with respect to the experimental data was evaluated. Results The parameter identification procedure led to minor model adjustments but considerably reduced the error in the predicted fingertip forces (root mean square error reduced from 0.53/0.69 N to 0.11/0.20 N for the human/bonobo model). Both models remained physiologically plausible after the parameter identification. In the combined loading scenario, fingertip and net metacarpal forces were predicted with average directional errors below 6° and magnitude errors below 12%. Conclusions This study presents the first attempt to implement both a human and non-human primate finger model for comparative palaeoanthropological studies. The good agreement between predicted and experimental forces involving the action of extrinsic flexors—which are most relevant for forceful grasping—shows that the models are likely sufficiently accurate for comparisons of internal loads occurring during human and non-human primate manual activities.
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Affiliation(s)
- Alexander Synek
- Institute of Lightweight Design and Structural Biomechanics, TU Wien, Vienna, Austria
| | - Szu-Ching Lu
- Laboratory for Innovation in Autism, School of Education, University of Strathclyde, Glasgow, United Kingdom.,Animal Postcranial Evolution Lab, Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, United Kingdom
| | - Evie E Vereecke
- Department of Development and Regeneration, University of Leuven, Kortrijk, Belgium
| | - Sandra Nauwelaerts
- Department of Biology, University of Antwerp, Wilrijk, Belgium.,Center for Research and Conservation KMDA, Astridplein, Antwerpen, Belgium
| | - Tracy L Kivell
- Animal Postcranial Evolution Lab, Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, United Kingdom.,Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Dieter H Pahr
- Institute of Lightweight Design and Structural Biomechanics, TU Wien, Vienna, Austria.,Department of Anatomy and Biomechanics, Karl Landsteiner Private University of Health Sciences, Krems an der Donau, Austria
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Dunmore CJ, Kivell TL, Bardo A, Skinner MM. Metacarpal trabecular bone varies with distinct hand-positions used in hominid locomotion. J Anat 2019; 235:45-66. [PMID: 31099419 PMCID: PMC6580057 DOI: 10.1111/joa.12966] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/22/2019] [Indexed: 12/11/2022] Open
Abstract
Trabecular bone remodels during life in response to loading and thus should, at least in part, reflect potential variation in the magnitude, frequency and direction of joint loading across different hominid species. Here we analyse the trabecular structure across all non-pollical metacarpal distal heads (Mc2-5) in extant great apes, expanding on previous volume of interest and whole-epiphysis analyses that have largely focused on only the first or third metacarpal. Specifically, we employ both a univariate statistical mapping and a multivariate approach to test for both inter-ray and interspecific differences in relative trabecular bone volume fraction (RBV/TV) and degree of anisotropy (DA) in Mc2-5 subchondral trabecular bone. Results demonstrate that whereas DA values only separate Pongo from African apes (Pan troglodytes, Pan paniscus, Gorilla gorilla), RBV/TV distribution varies with the predicted loading of the metacarpophalangeal (McP) joints during locomotor behaviours in each species. Gorilla exhibits a relatively dorsal distribution of RBV/TV consistent with habitual hyper-extension of the McP joints during knuckle-walking, whereas Pongo has a palmar distribution consistent with flexed McP joints used to grasp arboreal substrates. Both Pan species possess a disto-dorsal distribution of RBV/TV, compatible with multiple hand postures associated with a more varied locomotor regime. Further inter-ray comparisons reveal RBV/TV patterns consistent with varied knuckle-walking postures in Pan species in contrast to higher RBV/TV values toward the midline of the hand in Mc2 and Mc5 of Gorilla, consistent with habitual palm-back knuckle-walking. These patterns of trabecular bone distribution and structure reflect different behavioural signals that could be useful for determining the behaviours of fossil hominins.
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Affiliation(s)
- Christopher J. Dunmore
- Skeletal Biology Research CentreSchool of Anthropology and ConservationUniversity of KentCanterburyUK
| | - Tracy L. Kivell
- Skeletal Biology Research CentreSchool of Anthropology and ConservationUniversity of KentCanterburyUK
- Department of Human EvolutionMax Planck Institute for Evolutionary AnthropologyLeipzigGermany
| | - Ameline Bardo
- Skeletal Biology Research CentreSchool of Anthropology and ConservationUniversity of KentCanterburyUK
| | - Matthew M. Skinner
- Skeletal Biology Research CentreSchool of Anthropology and ConservationUniversity of KentCanterburyUK
- Department of Human EvolutionMax Planck Institute for Evolutionary AnthropologyLeipzigGermany
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Abstract
Studies of femoral trabecular structure have shown that the orientation and volume of bone are associated with variation in loading and could be informative about individual joint positioning during locomotion. In this study, we analyse for the first time trabecular bone patterns throughout the femoral head using a whole-epiphysis approach to investigate how potential trabecular variation in humans and great apes relates to differences in locomotor modes. Trabecular architecture was analysed using microCT scans of Pan troglodytes (n = 20), Gorilla gorilla (n = 14), Pongo sp. (n = 5) and Homo sapiens (n = 12) in medtool 4.1. Our results revealed differences in bone volume fraction (BV/TV) distribution patterns, as well as overall trabecular parameters of the femoral head between great apes and humans. Pan and Gorilla showed two regions of high BV/TV in the femoral head, consistent with hip posture and loading during two discrete locomotor modes: knuckle-walking and climbing. Most Pongo specimens also displayed two regions of high BV/TV, but these regions were less discrete and there was more variability across the sample. In contrast, Homo showed only one main region of high BV/TV in the femoral head and had the lowest BV/TV, as well as the most anisotropic trabeculae. The Homo trabecular structure is consistent with stereotypical loading with a more extended hip compared with great apes, which is characteristic of modern human bipedalism. Our results suggest that holistic evaluations of femoral head trabecular architecture can reveal previously undetected patterns linked to locomotor behaviour in extant apes and can provide further insight into hip joint loading in fossil hominins and other primates.
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Affiliation(s)
- Leoni Georgiou
- Skeletal Biology Research CentreSchool of Anthropology and ConservationUniversity of KentCanterburyUK
| | - Tracy L. Kivell
- Skeletal Biology Research CentreSchool of Anthropology and ConservationUniversity of KentCanterburyUK
- Department of Human EvolutionMax Planck Institute for Evolutionary AnthropologyLeipzigGermany
| | - Dieter H. Pahr
- Institute for Lightweight Design and Structural BiomechanicsVienna University of TechnologyViennaAustria
- Department of Anatomy and BiomechanicsKarl Landsteiner Private University of Health SciencesKrems an der DonauAustria
| | - Laura T. Buck
- Department of AnthropologyUniversity of CaliforniaDavisCAUSA
| | - Matthew M. Skinner
- Skeletal Biology Research CentreSchool of Anthropology and ConservationUniversity of KentCanterburyUK
- Department of Human EvolutionMax Planck Institute for Evolutionary AnthropologyLeipzigGermany
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24
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Synek A, Dunmore CJ, Kivell TL, Skinner MM, Pahr DH. Inverse remodelling algorithm identifies habitual manual activities of primates based on metacarpal bone architecture. Biomech Model Mechanobiol 2019; 18:399-410. [PMID: 30413983 PMCID: PMC6418057 DOI: 10.1007/s10237-018-1091-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 10/29/2018] [Indexed: 12/30/2022]
Abstract
Previously, a micro-finite element (micro-FE)-based inverse remodelling method was presented in the literature that reconstructs the loading history of a bone based on its architecture alone. Despite promising preliminary results, it remains unclear whether this method is sensitive enough to detect differences of bone loading related to pathologies or habitual activities. The goal of this study was to test the sensitivity of the inverse remodelling method by predicting joint loading histories of metacarpal bones of species with similar anatomy but clearly distinct habitual hand use. Three groups of habitual hand use were defined using the most representative primate species: manipulation (human), suspensory locomotion (orangutan), and knuckle-walking locomotion (bonobo, chimpanzee, gorilla). Nine to ten micro-computed tomography scans of each species ([Formula: see text] in total) were used to create micro-FE models of the metacarpal head region. The most probable joint loading history was predicted by optimally scaling six load cases representing joint postures ranging from [Formula: see text] (extension) to [Formula: see text] (flexion). Predicted mean joint load directions were significantly different between knuckle-walking and non-knuckle-walking groups ([Formula: see text]) and in line with expected primary hand postures. Mean joint load magnitudes tended to be larger in species using their hands for locomotion compared to species using them for manipulation. In conclusion, this study shows that the micro-FE-based inverse remodelling method is sensitive enough to detect differences of joint loading related to habitual manual activities of primates and might, therefore, be useful for palaeoanthropologists to reconstruct the behaviour of extinct species and for biomedical applications such as detecting pathological joint loading.
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Affiliation(s)
- Alexander Synek
- Institute of Lightweight Design and Structural Biomechanics, TU Wien, Getreidemarkt 9/BE, Vienna, Austria.
| | - Christopher J Dunmore
- Animal Postcranial Evolution Lab, Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, UK
| | - Tracy L Kivell
- Animal Postcranial Evolution Lab, Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, UK
- Department of Human Evolution, Max Plank Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Matthew M Skinner
- Animal Postcranial Evolution Lab, Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, UK
- Department of Human Evolution, Max Plank Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Dieter H Pahr
- Institute of Lightweight Design and Structural Biomechanics, TU Wien, Getreidemarkt 9/BE, Vienna, Austria
- Department of Anatomy and Biomechanics, Karl Landsteiner Private University of Health Sciences, Krems an der Donau, Austria
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25
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Ríos L, Kivell TL, Lalueza-Fox C, Estalrrich A, García-Tabernero A, Huguet R, Quintino Y, de la Rasilla M, Rosas A. Skeletal Anomalies in The Neandertal Family of El Sidrón (Spain) Support A Role of Inbreeding in Neandertal Extinction. Sci Rep 2019; 9:1697. [PMID: 30737446 PMCID: PMC6368597 DOI: 10.1038/s41598-019-38571-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Accepted: 12/31/2018] [Indexed: 12/12/2022] Open
Abstract
Neandertals disappeared from the fossil record around 40,000 bp, after a demographic history of small and isolated groups with high but variable levels of inbreeding, and episodes of interbreeding with other Paleolithic hominins. It is reasonable to expect that high levels of endogamy could be expressed in the skeleton of at least some Neandertal groups. Genetic studies indicate that the 13 individuals from the site of El Sidrón, Spain, dated around 49,000 bp, constituted a closely related kin group, making these Neandertals an appropriate case study for the observation of skeletal signs of inbreeding. We present the complete study of the 1674 identified skeletal specimens from El Sidrón. Altogether, 17 congenital anomalies were observed (narrowing of the internal nasal fossa, retained deciduous canine, clefts of the first cervical vertebra, unilateral hypoplasia of the second cervical vertebra, clefting of the twelfth thoracic vertebra, diminutive thoracic or lumbar rib, os centrale carpi and bipartite scaphoid, tripartite patella, left foot anomaly and cuboid-navicular coalition), with at least four individuals presenting congenital conditions (clefts of the first cervical vertebra). At 49,000 years ago, the Neandertals from El Sidrón, with genetic and skeletal evidence of inbreeding, could be representative of the beginning of the demographic collapse of this hominin phenotype.
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Affiliation(s)
- L Ríos
- Department of Physical Anthropology, Aranzadi Zientzia Elkartea, Zorroagagaina 11, 20014, Donostia, Gipuzkoa, Basque Country, Spain.
| | - T L Kivell
- Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Marlowe Building, Canterbury, CT2 7NR, UK.,Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, Leipzig, 04103, Germany
| | - C Lalueza-Fox
- Institute of Evolutionary Biology (CSIC-Universitat Pompeu Fabra), Carrer Dr. Aiguader 88, 08003, Barcelona, Spain
| | - A Estalrrich
- Instituto Internacional de Investigaciones Prehistóricas de Cantabria IIIPC (Universidad de Cantabria, Santander, Gobierno de Cantabria), Avda. de los Castros 52, 39005, Santander, Cantabria, Spain
| | - A García-Tabernero
- Paleoanthropology Group, Department of Paleobiology. Museo Nacional de Ciencias Naturales (MNCN-CSIC), José Gutiérrez Abascal 2, 28006, Madrid, Spain
| | - R Huguet
- IPHES, Institut Catala de Paleoecologia Humana i Evolució Social, Campus Sescelades URV (Edifici W3), 43007, Tarragona, Spain.,Area de Prehistoria, Universitat Rovira i Virgili, Avda. Catalunya 35, 43002, Tarragona, Spain.,Unidad asociada al CSIC, Departamento de Paleobiología, Museo Nacional de Ciencias Naturales, Calle José Gutierrez Abascal 2, 28006, Madrid, Spain
| | - Y Quintino
- Laboratorio de Evolución Humana, Dpto. de Ciencias Históricas y Geografía, Universidad de Burgos, Edificio I+D+i, Plaza Misael Bañuelos s/n, 09001, Burgos, Spain
| | - M de la Rasilla
- Área de Prehistoria Departamento de Historia, Universidad de Oviedo, Calle Teniente Alfonso Martínez s/n, 33011, Oviedo, Spain
| | - A Rosas
- Paleoanthropology Group, Department of Paleobiology. Museo Nacional de Ciencias Naturales (MNCN-CSIC), José Gutiérrez Abascal 2, 28006, Madrid, Spain.
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26
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Key A, Merritt SR, Kivell TL. Hand grip diversity and frequency during the use of Lower Palaeolithic stone cutting-tools. J Hum Evol 2018; 125:137-158. [DOI: 10.1016/j.jhevol.2018.08.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Revised: 08/21/2018] [Accepted: 08/22/2018] [Indexed: 11/15/2022]
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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28
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Lu SC, Vereecke EE, Synek A, Pahr DH, Kivell TL. A novel experimental design for the measurement of metacarpal bone loading and deformation and fingertip force. PeerJ 2018; 6:e5480. [PMID: 30221084 PMCID: PMC6138040 DOI: 10.7717/peerj.5480] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2018] [Accepted: 07/30/2018] [Indexed: 12/15/2022] Open
Abstract
Background Musculoskeletal and finite element modelling are often used to predict joint loading and bone strength within the human hand, but there is a lack of in vitro evidence of the force and strain experienced by hand bones. Methods This study presents a novel experimental setup that allows the positioning of a cadaveric digit in a variety of postures with the measurement of force and strain experienced by the third metacarpal. The setup allows for the measurement of fingertip force as well. We tested this experimental setup using three cadaveric human third digits in which the flexor tendons were loaded in two tendon pathways: (1) parallel to the metacarpal bone shaft, with bowstringing; (2) a semi-physiological condition in which the tendons were positioned closer to the bone shaft. Results There is substantial variation in metacarpal net force, metacarpal strain and fingertip force between the two tendon pathways. The net force acting on the metacarpal bone is oriented palmarly in the parallel tendon condition, causing tension along the dorsum of the metacarpal shaft, while the force increases and is oriented dorsally in the semi-physiological condition, causing compression of the dorsal metacarpal shaft. Fingertip force is also greater in the semi-physiological condition, implying a more efficient grip function. Inter-individual variation is observed in the radioulnar orientation of the force experienced by the metacarpal bone, the fingertip force, and the strain patterns on the metacarpal shaft. Conclusion This study demonstrates a new method for measuring force and strain experienced by the metacarpal, and fingertip force in cadaveric digits that can, in turn, inform computation models. Inter-individual variation in loads experienced by the third digit suggest that there are differences in joint contact and/or internal bone structure across individuals that are important to consider in clinical and evolutionary contexts.
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Affiliation(s)
- Szu-Ching Lu
- Animal Postcranial Evolution Lab, Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, UK
| | - Evie E Vereecke
- Department of Development and Regeneration, University of Leuven, Kortrijk, Belgium
| | - Alexander Synek
- Institute of Lightweight Design and Structural Biomechanics, Vienna University of Technology, Vienna, Austria
| | - Dieter H Pahr
- Institute of Lightweight Design and Structural Biomechanics, Vienna University of Technology, Vienna, Austria.,Department of Anatomy and Biomechanics, Karl Landsteiner Private University of Health Sciences, Krems an der Donau, Austria
| | - Tracy L Kivell
- Animal Postcranial Evolution Lab, Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, UK.,Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
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29
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Tsegai ZJ, Skinner MM, Pahr DH, Hublin JJ, Kivell TL. Ontogeny and variability of trabecular bone in the chimpanzee humerus, femur and tibia. Am J Phys Anthropol 2018; 167:713-736. [DOI: 10.1002/ajpa.23696] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 06/22/2018] [Accepted: 07/23/2018] [Indexed: 12/26/2022]
Affiliation(s)
- Zewdi J. Tsegai
- Department of Human Evolution; Max Planck Institute for Evolutionary Anthropology; Leipzig Germany
| | - Matthew M. Skinner
- Skeletal Biology Research Center; School of Anthropology and Conservation, University of Kent; Canterbury United Kingdom
- Department of Human Evolution; Max Planck Institute for Evolutionary Anthropology; Leipzig Germany
| | - Dieter H. Pahr
- Institute for Lightweight Design and Structural Biomechanics; Vienna University of Technology; Wien Austria
| | - Jean-Jacques Hublin
- Department of Human Evolution; Max Planck Institute for Evolutionary Anthropology; Leipzig Germany
| | - Tracy L. Kivell
- Skeletal Biology Research Center; School of Anthropology and Conservation, University of Kent; Canterbury United Kingdom
- Department of Human Evolution; Max Planck Institute for Evolutionary Anthropology; Leipzig Germany
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30
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Kivell TL, Davenport R, Hublin JJ, Thackeray JF, Skinner MM. Trabecular architecture and joint loading of the proximal humerus in extant hominoids, Ateles, and Australopithecus africanus. Am J Phys Anthropol 2018; 167:348-365. [PMID: 30129074 DOI: 10.1002/ajpa.23635] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 05/30/2018] [Accepted: 06/01/2018] [Indexed: 01/15/2023]
Abstract
OBJECTIVES Several studies have investigated potential functional signals in the trabecular structure of the primate proximal humerus but with varied success. Here, we apply for the first time a "whole-epiphyses" approach to analysing trabecular bone in the humeral head with the aim of providing a more holistic interpretation of trabecular variation in relation to habitual locomotor or manipulative behaviors in several extant primates and Australopithecus africanus. MATERIALS AND METHODS We use a "whole-epiphysis" methodology in comparison to the traditional volume of interest (VOI) approach to investigate variation in trabecular structure and joint loading in the proximal humerus of extant hominoids, Ateles and A. africanus (StW 328). RESULTS There are important differences in the quantification of trabecular parameters using a "whole-epiphysis" versus a VOI-based approach. Variation in trabecular structure across knuckle-walking African apes, suspensory taxa, and modern humans was generally consistent with predictions of load magnitude and inferred joint posture during habitual behaviors. Higher relative trabecular bone volume and more isotropic trabeculae in StW 328 suggest A. africanus may have still used its forelimbs for arboreal locomotion. DISCUSSION A whole-epiphysis approach to analysing trabecular structure of the proximal humerus can help distinguish functional signals of joint loading across extant primates and can provide novel insight into habitual behaviors of fossil hominins.
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Affiliation(s)
- Tracy L Kivell
- School of Anthropology and Conservation, Skeletal Biology Research Centre, University of Kent, Canterbury, United Kingdom.,Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.,Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa
| | - Rebecca Davenport
- Department of Anthropology, University College London, London, United Kingdom
| | - Jean-Jacques Hublin
- Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - J Francis Thackeray
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa
| | - Matthew M Skinner
- School of Anthropology and Conservation, Skeletal Biology Research Centre, University of Kent, Canterbury, United Kingdom.,Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.,Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa
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31
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Stephens NB, Kivell TL, Pahr DH, Hublin JJ, Skinner MM. Trabecular bone patterning across the human hand. J Hum Evol 2018; 123:1-23. [PMID: 30072187 DOI: 10.1016/j.jhevol.2018.05.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Revised: 05/09/2018] [Accepted: 05/10/2018] [Indexed: 02/06/2023]
Abstract
Hand bone morphology is regularly used to link particular hominin species with behaviors relevant to cognitive/technological progress. Debates about the functional significance of differing hominin hand bone morphologies tend to rely on establishing phylogenetic relationships and/or inferring behavior from epigenetic variation arising from mechanical loading and adaptive bone modeling. Most research focuses on variation in cortical bone structure, but additional information about hand function may be provided through the analysis of internal trabecular structure. While primate hand bone trabecular structure is known to vary in ways that are consistent with expected joint loading differences during manipulation and locomotion, no study exists that has documented this variation across the numerous bones of the hand. We quantify the trabecular structure in 22 bones of the human hand (early/extant modern Homo sapiens) and compare structural variation between two groups associated with post-agricultural/industrial (post-Neolithic) and foraging/hunter-gatherer (forager) subsistence strategies. We (1) establish trabecular bone volume fraction (BV/TV), modulus (E), degree of anisotropy (DA), mean trabecular thickness (Tb.Th) and spacing (Tb.Sp); (2) visualize the average distribution of site-specific BV/TV for each bone; and (3) examine if the variation in trabecular structure is consistent with expected joint loading differences among the regions of the hand and between the groups. Results indicate similar distributions of trabecular bone in both groups, with those of the forager sample presenting higher BV/TV, E, and lower DA, suggesting greater and more variable loading during manipulation. We find indications of higher loading along the ulnar side of the forager sample hand, with high site-specific BV/TV distributions among the carpals that are suggestive of high loading while the wrist moves through the 'dart-thrower's' motion. These results support the use of trabecular structure to infer behavior and have direct implications for refining our understanding of human hand evolution and fossil hominin hand use.
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Affiliation(s)
- Nicholas B Stephens
- Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103 Leipzig, Germany.
| | - Tracy L Kivell
- Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury CT2 7NZ, United Kingdom; Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103 Leipzig, Germany
| | - Dieter H Pahr
- Institute for Lightweight Design and Structural Biomechanics, Vienna University of Technology, Getreidemarkt 9, A-1060 Vienna, Austria
| | - Jean-Jacques Hublin
- Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103 Leipzig, Germany
| | - Matthew M Skinner
- Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury CT2 7NZ, United Kingdom; Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103 Leipzig, Germany
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32
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Neufuss J, Robbins MM, Baeumer J, Humle T, Kivell TL. Manual skills for food processing by mountain gorillas (Gorilla beringei beringei) in Bwindi Impenetrable National Park, Uganda. Biol J Linn Soc Lond 2018. [DOI: 10.1093/biolinnean/bly071] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Johanna Neufuss
- Animal Postcranial Evolution (APE) Laboratory, Skeletal Biology Research Centre, School of Anthropology & Conservation, University of Kent, Canterbury, UK
| | - 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, UK
| | - Tracy L Kivell
- Animal Postcranial Evolution (APE) Laboratory, Skeletal Biology Research Centre, School of Anthropology & Conservation, University of Kent, Canterbury, UK
- Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
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33
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Abstract
BACKGROUND In addition to external bone shape and cortical bone thickness and distribution, the distribution and orientation of internal trabecular bone across individuals and species has yielded important functional information on how bone adapts in response to load. In particular, trabecular bone analysis has played a key role in studies of human and nonhuman primate locomotion and has shown that species with different locomotor repertoires display distinct trabecular architecture in various regions of the skeleton. In this study, we analyse trabecular structure throughout the distal femur of extant hominoids and test for differences due to locomotor loading regime. METHODS Micro-computed tomography scans of Homo sapiens (n = 11), Pan troglodytes (n = 18), Gorilla gorilla (n = 14) and Pongo sp. (n = 7) were used to investigate trabecular structure throughout the distal epiphysis of the femur. We predicted that bone volume fraction (BV/TV) in the medial and lateral condyles in Homo would be distally concentrated and more anisotropic due to a habitual extended knee posture at the point of peak ground reaction force during bipedal locomotion, whereas great apes would show more posteriorly concentrated BV/TV and greater isotropy due to a flexed knee posture and more variable hindlimb use during locomotion. RESULTS Results indicate some significant differences between taxa, with the most prominent being higher BV/TV in the posterosuperior region of the condyles in Pan and higher BV/TV and anisotropy in the posteroinferior region in Homo. Furthermore, trabecular number, spacing and thickness differ significantly, mainly separating Gorilla from the other apes. DISCUSSION The trabecular architecture of the distal femur holds a functional signal linked to habitual behaviour; however, there was more similarity across taxa and greater intraspecific variability than expected. Specifically, there was a large degree of overlap in trabecular structure across the sample, and Homo was not as distinct as predicted. Nonetheless, this study offers a comparative sample of trabecular structure in the hominoid distal femur and can contribute to future studies of locomotion in extinct taxa.
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Affiliation(s)
- Leoni Georgiou
- Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent at Canterbury, Canterbury, Kent, UK
| | - Tracy L. Kivell
- Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent at Canterbury, Canterbury, Kent, UK
- Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Dieter H. Pahr
- Institute for Lightweight Design and Structural Biomechanics, Vienna University of Technology, Vienna, Austria
- Department of Anatomy and Biomechanics, Karl Landsteiner Private University of Health Sciences, Krems an der Donau, Austria
| | - Matthew M. Skinner
- Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent at Canterbury, Canterbury, Kent, UK
- Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
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Williams-Hatala EM, Hatala KG, Gordon M, Key A, Kasper M, Kivell TL. The manual pressures of stone tool behaviors and their implications for the evolution of the human hand. J Hum Evol 2018; 119:14-26. [DOI: 10.1016/j.jhevol.2018.02.008] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Revised: 02/15/2018] [Accepted: 02/16/2018] [Indexed: 11/26/2022]
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Groucutt HS, Grün R, Zalmout IAS, Drake NA, Armitage SJ, Candy I, Clark-Wilson R, Louys J, Breeze PS, Duval M, Buck LT, Kivell TL, Pomeroy E, Stephens NB, Stock JT, Stewart M, Price GJ, Kinsley L, Sung WW, Alsharekh A, Al-Omari A, Zahir M, Memesh AM, Abdulshakoor AJ, Al-Masari AM, Bahameem AA, Al Murayyi KMS, Zahrani B, Scerri ELM, Petraglia MD. Homo sapiens in Arabia by 85,000 years ago. Nat Ecol Evol 2018; 2:800-809. [PMID: 29632352 PMCID: PMC5935238 DOI: 10.1038/s41559-018-0518-2] [Citation(s) in RCA: 115] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Accepted: 02/26/2018] [Indexed: 02/07/2023]
Abstract
Understanding the timing and character of the expansion of Homo sapiens out of Africa is critical for inferring the colonization and admixture processes that underpin global population history. It has been argued that dispersal out of Africa had an early phase, particularly ~130-90 thousand years ago (ka), that reached only the East Mediterranean Levant, and a later phase, ~60-50 ka, that extended across the diverse environments of Eurasia to Sahul. However, recent findings from East Asia and Sahul challenge this model. Here we show that H. sapiens was in the Arabian Peninsula before 85 ka. We describe the Al Wusta-1 (AW-1) intermediate phalanx from the site of Al Wusta in the Nefud desert, Saudi Arabia. AW-1 is the oldest directly dated fossil of our species outside Africa and the Levant. The palaeoenvironmental context of Al Wusta demonstrates that H. sapiens using Middle Palaeolithic stone tools dispersed into Arabia during a phase of increased precipitation driven by orbital forcing, in association with a primarily African fauna. A Bayesian model incorporating independent chronometric age estimates indicates a chronology for Al Wusta of ~95-86 ka, which we correlate with a humid episode in the later part of Marine Isotope Stage 5 known from various regional records. Al Wusta shows that early dispersals were more spatially and temporally extensive than previously thought. Early H. sapiens dispersals out of Africa were not limited to winter rainfall-fed Levantine Mediterranean woodlands immediately adjacent to Africa, but extended deep into the semi-arid grasslands of Arabia, facilitated by periods of enhanced monsoonal rainfall.
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Affiliation(s)
- Huw S Groucutt
- School of Archaeology, Research Laboratory for Archaeology and the History of Art, University of Oxford, Oxford, UK.
- Department of Archaeology, Max Planck Institute for the Science of Human History, Jena, Germany.
| | - Rainer Grün
- Australian Research Centre for Human Evolution (ARCHE), Environmental Futures Research Institute, Griffith University, Nathan, Queensland, Australia
- Research School of Earth Sciences, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Iyad A S Zalmout
- Saudi Geological Survey, Sedimentary Rocks and Palaeontology Department, Jeddah, Saudi Arabia
| | - Nick A Drake
- Department of Archaeology, Max Planck Institute for the Science of Human History, Jena, Germany
- Department of Geography, King's College London, London, UK
| | - Simon J Armitage
- Department of Geography, Royal Holloway, University of London, London, UK
- SFF Centre for Early Sapiens Behaviour (SapienCE), University of Bergen, Bergen, Norway
| | - Ian Candy
- Department of Geography, Royal Holloway, University of London, London, UK
| | | | - Julien Louys
- Australian Research Centre for Human Evolution (ARCHE), Environmental Futures Research Institute, Griffith University, Nathan, Queensland, Australia
| | - Paul S Breeze
- Department of Geography, King's College London, London, UK
| | - Mathieu Duval
- Australian Research Centre for Human Evolution (ARCHE), Environmental Futures Research Institute, Griffith University, Nathan, Queensland, Australia
- Geochronology, Centro Nacional de Investigación sobre la Evolución (CENIEH), Burgos, Spain
| | - Laura T Buck
- PAVE Research Group, Department of Archaeology, University of Cambridge, Cambridge, UK
- Earth Sciences Department, Natural History Museum, London, UK
| | - Tracy L Kivell
- Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, UK
- Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Emma Pomeroy
- PAVE Research Group, Department of Archaeology, University of Cambridge, Cambridge, UK
- School of Natural Sciences and Psychology, Liverpool John Moores University, Liverpool, UK
| | - Nicholas B Stephens
- Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Jay T Stock
- PAVE Research Group, Department of Archaeology, University of Cambridge, Cambridge, UK
- Department of Anthropology, University of Western Ontario, London, Ontario, Canada
| | - Mathew Stewart
- Palaeontology, Geobiology and Earth Archives Research Centre, School of Biological, Earth and Environmental Science, University of New South Wales, Sydney, New South Wales, Australia
| | - Gilbert J Price
- School of Earth and Environmental Sciences, The University of Queensland, St Lucia, Queensland, Australia
| | - Leslie Kinsley
- Research School of Earth Sciences, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Wing Wai Sung
- Department of Life Sciences, Natural History Museum, London, UK
| | | | - Abdulaziz Al-Omari
- Saudi Commission for Tourism and National Heritage, Riyadh, Saudi Arabia
| | - Muhammad Zahir
- Department of Archaeology, Hazara University, Mansehra, Pakistan
| | - Abdullah M Memesh
- Saudi Geological Survey, Sedimentary Rocks and Palaeontology Department, Jeddah, Saudi Arabia
| | - Ammar J Abdulshakoor
- Saudi Geological Survey, Sedimentary Rocks and Palaeontology Department, Jeddah, Saudi Arabia
| | - Abdu M Al-Masari
- Saudi Geological Survey, Sedimentary Rocks and Palaeontology Department, Jeddah, Saudi Arabia
| | - Ahmed A Bahameem
- Saudi Geological Survey, Sedimentary Rocks and Palaeontology Department, Jeddah, Saudi Arabia
| | | | - Badr Zahrani
- Saudi Commission for Tourism and National Heritage, Riyadh, Saudi Arabia
| | - Eleanor L M Scerri
- School of Archaeology, Research Laboratory for Archaeology and the History of Art, University of Oxford, Oxford, UK
- Department of Archaeology, Max Planck Institute for the Science of Human History, Jena, Germany
| | - Michael D Petraglia
- Department of Archaeology, Max Planck Institute for the Science of Human History, Jena, Germany.
- Human Origins Program, National Museum of Natural History, Smithsonian Institution, Washington DC, USA.
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Tsegai ZJ, Skinner MM, Pahr DH, Hublin J, Kivell TL. Systemic patterns of trabecular bone across the human and chimpanzee skeleton. J Anat 2018; 232:641-656. [PMID: 29344941 PMCID: PMC5835784 DOI: 10.1111/joa.12776] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/07/2017] [Indexed: 12/18/2022] Open
Abstract
Aspects of trabecular bone architecture are thought to reflect regional loading of the skeleton, and thus differ between primate taxa with different locomotor and postural modes. However, there are several systemic factors that affect bone structure that could contribute to, or be the primary factor determining, interspecific differences in bone structure. These systemic factors include differences in genetic regulation, sensitivity to loading, hormone levels, diet, and activity levels. Improved understanding of inter-/intraspecific variability, and variability across the skeleton of an individual, is required to interpret properly potential functional signals present within trabecular structure. Using a whole-region method of analysis, we investigated trabecular structure throughout the skeleton of humans and chimpanzees. Trabecular bone volume fraction (BV/TV), degree of anisotropy (DA) and trabecular thickness (Tb.Th) were quantified from high resolution micro-computed tomographic scans of the humeral and femoral head, third metacarpal and third metatarsal head, distal tibia, talus and first thoracic vertebra. We found that BV/TV is, in most anatomical sites, significantly higher in chimpanzees than in humans, suggesting a systemic difference in trabecular structure unrelated to local loading regime. Differences in BV/TV between the forelimb and hindlimb did not clearly reflect differences in locomotor loading in the study taxa. There were no clear systemic differences between the taxa in DA and, as such, this parameter might reflect function and relate to differences in joint loading. This systemic approach reveals both the pattern of variability across the skeleton and between taxa, and helps identify those features of trabecular structure that may relate to joint function.
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Affiliation(s)
- Zewdi J. Tsegai
- Department of Human EvolutionMax Planck Institute for Evolutionary AnthropologyLeipzigGermany
| | - Matthew M. Skinner
- Department of Human EvolutionMax Planck Institute for Evolutionary AnthropologyLeipzigGermany
- Skeletal Biology Research CentreSchool of Anthropology and ConservationUniversity of KentCanterburyUK
| | - Dieter H. Pahr
- Institute of Lightweight Design and Structural BiomechanicsVienna University of TechnologyViennaAustria
| | - Jean‐Jacques Hublin
- Department of Human EvolutionMax Planck Institute for Evolutionary AnthropologyLeipzigGermany
| | - Tracy L. Kivell
- Department of Human EvolutionMax Planck Institute for Evolutionary AnthropologyLeipzigGermany
- Skeletal Biology Research CentreSchool of Anthropology and ConservationUniversity of KentCanterburyUK
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Abstract
Evolution of the human hand has undergone a transition from use during locomotion to use primarily for manipulation. Previous comparative morphological and biomechanical studies have focused on potential changes in manipulative abilities during human hand evolution, but few have focused on functional signals for arboreal locomotion. Here, we provide this comparative context though the first analysis of hand loading in captive bonobos during arboreal locomotion. We quantify pressure experienced by the fingers, palm and thumb in bonobos during vertical locomotion, suspension and arboreal knuckle-walking. Results show that pressure experienced by the fingers is significantly higher during knuckle-walking compared with similar pressures experienced by the fingers and palm during suspensory and vertical locomotion. Peak pressure is most often experienced at or around the third digit in all locomotor modes. Pressure quantified for the thumb is either very low or absent, despite the thumb making contact with the substrate during all suspensory and vertical locomotor trials. Unlike chimpanzees, the bonobos do not show a rolling pattern of digit contact with the substrate during arboreal knuckle-walking but, instead, digits 3 and 4 typically touch down first and digit 5 almost always made contact with the substrate. These results have implications for interpreting extant and fossilised hand morphology; we expect bonobo (and chimpanzee) bony morphology to primarily reflect the biomechanical loading of knuckle-walking, while functional signals for arboreal locomotion in fossil hominins are most likely to appear in the fingers, particularly digit 3, and least likely to appear in the morphology of the thumb.
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Affiliation(s)
- Diana S. Samuel
- Animal Postcranial Evolution (APE) Lab, Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury CT2 7NR, UK
| | - Sandra Nauwelaerts
- Laboratory for Functional morphology, Department of Biology, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium
- Centre for Research and Conservation (CRC), Koningin Astridplein 20-26, 2018 Antwerp, Belgium
| | - Jeroen M. G. Stevens
- Centre for Research and Conservation (CRC), Koningin Astridplein 20-26, 2018 Antwerp, Belgium
- Behavioral Ecology and Ecophysiology group, Department of Biology, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - Tracy L. Kivell
- Animal Postcranial Evolution (APE) Lab, Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury CT2 7NR, UK
- Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, Leipzig 04103, Germany
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Kivell TL, Rosas A, Estalrrich A, Huguet R, García-Tabernero A, Ríos L, de la Rasilla M. New Neandertal wrist bones from El Sidrón, Spain (1994-2009). J Hum Evol 2017; 114:45-75. [PMID: 29447761 DOI: 10.1016/j.jhevol.2017.09.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Revised: 09/12/2017] [Accepted: 09/13/2017] [Indexed: 01/07/2023]
Abstract
Twenty-nine carpal bones of Homo neanderthalensis have been recovered from the site of El Sidrón (Asturias, Spain) during excavations between 1994 and 2009, alongside ∼2500 other Neandertal skeletal elements dated to ∼49,000 years ago. All bones of the wrist are represented, including adult scaphoids (n = 6), lunates (n = 2), triquetra (n = 4), pisiforms (n = 2), trapezia (n = 2), trapezoids (n = 5), capitates (n = 5), and hamates (n = 2), as well as one fragmentary and possibly juvenile scaphoid. Several of these carpals appear to belong to the complete right wrist of a single individual. Here we provide qualitative and quantitative morphological descriptions of these carpals, within a comparative context of other European and Near Eastern Neandertals, early and recent Homo sapiens, and other fossil hominins, including Homo antecessor, Homo naledi, and australopiths. Overall, the El Sidrón carpals show characteristics that typically distinguish Neandertals from H. sapiens, such as a relatively flat first metacarpal facet on the trapezium and a more laterally oriented second metacarpal facet on the capitate. However, there are some distinctive features of the El Sidrón carpals compared with most other Neandertals. For example, the tubercle of the trapezium is small with limited projection, while the scaphoid tubercle and hamate hamulus are among the largest seen in other Neandertals. Furthermore, three of the six adult scaphoids show a distinctive os-centrale portion, while another is a bipartite scaphoid with a truncated tubercle. The high frequency of rare carpal morphologies supports other evidence of a close genetic relationship among the Neandertals found at El Sidrón.
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Affiliation(s)
- Tracy L Kivell
- Animal Postcranial Evolution (APE) Lab, Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, UK; Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.
| | - Antonio Rosas
- Paleoanthropology Group, Department of Paleobiology, Museo Nacional de Ciencias Naturales (MNCN)-Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
| | - Almudena Estalrrich
- Paleoanthropology Group, Department of Paleobiology, Museo Nacional de Ciencias Naturales (MNCN)-Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain; Department of Paleoanthropology, Senckenberg Research Institute and Natural History Museum Frankfurt, Frankfurt am Main, Germany
| | - Rosa Huguet
- Institut Català de Paleoecologia Humana i Evolució Social-Unidad Asociada al CSIC, Tarragona, Spain
| | - Antonio García-Tabernero
- Paleoanthropology Group, Department of Paleobiology, Museo Nacional de Ciencias Naturales (MNCN)-Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
| | - Luis Ríos
- Paleoanthropology Group, Department of Paleobiology, Museo Nacional de Ciencias Naturales (MNCN)-Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
| | - Marco de la Rasilla
- Área de Prehistoria Departamento de Historia, Universidad de Oviedo, Oviedo, Spain
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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). Am J Phys Anthropol 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] [What about the content of this article? (0)] [Affiliation(s)] [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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40
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Tsegai ZJ, Skinner MM, Gee AH, Pahr DH, Treece GM, Hublin JJ, Kivell TL. Trabecular and cortical bone structure of the talus and distal tibia in Pan and Homo. Am J Phys Anthropol 2017; 163:784-805. [PMID: 28542704 DOI: 10.1002/ajpa.23249] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Revised: 04/20/2017] [Accepted: 05/03/2017] [Indexed: 02/01/2023]
Abstract
OBJECTIVES Internal bone structure, both cortical and trabecular bone, remodels in response to loading and may provide important information regarding behavior. The foot is well suited to analysis of internal bone structure because it experiences the initial substrate reaction forces, due to its proximity to the substrate. Moreover, as humans and apes differ in loading of the foot, this region is relevant to questions concerning arboreal locomotion and bipedality in the hominoid fossil record. MATERIALS AND METHODS We apply a whole-bone/epiphysis approach to analyze trabecular and cortical bone in the distal tibia and talus of Pan troglodytes and Homo sapiens. We quantify bone volume fraction (BV/TV), degree of anisotropy (DA), trabecular thickness (Tb.Th), bone surface to volume ratio (BS/BV), and cortical thickness and investigate the distribution of BV/TV and cortical thickness throughout the bone/epiphysis. RESULTS We find that Pan has a greater BV/TV, a lower BS/BV and thicker cortices than Homo in both the talus and distal tibia. The trabecular structure of the talus is more divergent than the tibia, having thicker, less uniformly aligned trabeculae in Pan compared to Homo. Differences in dorsiflexion at the talocrural joint and in degree of mobility at the talonavicular joint are reflected in the distribution of cortical and trabecular bone. DISCUSSION Overall, quantified trabecular parameters represent overall differences in bone strength between the two species, however, DA may be directly related to joint loading. Cortical and trabecular bone distributions correlate with habitual joint positions adopted by each species, and thus have potential for interpreting joint position in fossil hominoids.
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Affiliation(s)
- Zewdi J Tsegai
- Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Matthew M Skinner
- Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.,Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, United Kingdom
| | - Andrew H Gee
- Department of Engineering, University of Cambridge, Cambridge, United Kingdom
| | - Dieter H Pahr
- Institute for Lightweight Design and Structural Biomechanics, Vienna University of Technology, Wien, Austria
| | - Graham M Treece
- Department of Engineering, University of Cambridge, Cambridge, United Kingdom
| | - Jean-Jacques Hublin
- Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Tracy L Kivell
- Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.,Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, United Kingdom
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Hawks J, Elliott M, Schmid P, Churchill SE, Ruiter DJD, Roberts EM, Hilbert-Wolf H, Garvin HM, Williams SA, Delezene LK, Feuerriegel EM, Randolph-Quinney P, Kivell TL, Laird MF, Tawane G, DeSilva JM, Bailey SE, Brophy JK, Meyer MR, Skinner MM, Tocheri MW, VanSickle C, Walker CS, Campbell TL, Kuhn B, Kruger A, Tucker S, Gurtov A, Hlophe N, Hunter R, Morris H, Peixotto B, Ramalepa M, Rooyen DV, Tsikoane M, Boshoff P, Dirks PH, Berger LR. New fossil remains of Homo naledi from the Lesedi Chamber, South Africa. eLife 2017; 6. [PMID: 28483039 PMCID: PMC5423776 DOI: 10.7554/elife.24232] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 04/18/2017] [Indexed: 01/06/2023] Open
Abstract
The Rising Star cave system has produced abundant fossil hominin remains within the Dinaledi Chamber, representing a minimum of 15 individuals attributed to Homo naledi. Further exploration led to the discovery of hominin material, now comprising 131 hominin specimens, within a second chamber, the Lesedi Chamber. The Lesedi Chamber is far separated from the Dinaledi Chamber within the Rising Star cave system, and represents a second depositional context for hominin remains. In each of three collection areas within the Lesedi Chamber, diagnostic skeletal material allows a clear attribution to H. naledi. Both adult and immature material is present. The hominin remains represent at least three individuals based upon duplication of elements, but more individuals are likely present based upon the spatial context. The most significant specimen is the near-complete cranium of a large individual, designated LES1, with an endocranial volume of approximately 610 ml and associated postcranial remains. The Lesedi Chamber skeletal sample extends our knowledge of the morphology and variation of H. naledi, and evidence of H. naledi from both recovery localities shows a consistent pattern of differentiation from other hominin species.
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Affiliation(s)
- John Hawks
- Evolutionary Studies Institute, University of the Witwatersrand, Wits, South Africa.,Department of Anthropology, University of Wisconsin, Madison, United States
| | - Marina Elliott
- Evolutionary Studies Institute, University of the Witwatersrand, Wits, South Africa
| | - Peter Schmid
- Evolutionary Studies Institute, University of the Witwatersrand, Wits, South Africa.,Anthropological Institute and Museum, University of Zürich, Winterthurerstr, Zürich, Switzerland
| | - Steven E Churchill
- Evolutionary Studies Institute, University of the Witwatersrand, Wits, South Africa.,Department of Evolutionary Anthropology, Duke University, Durham, United States
| | - Darryl J de Ruiter
- Evolutionary Studies Institute, University of the Witwatersrand, Wits, South Africa.,Department of Anthropology, Texas A&M University, College Station, United States
| | - Eric M Roberts
- Geosciences, College of Science and Engineering, James Cook University, Townsville, Australia
| | - Hannah Hilbert-Wolf
- Geosciences, College of Science and Engineering, James Cook University, Townsville, Australia
| | - Heather M Garvin
- Evolutionary Studies Institute, University of the Witwatersrand, Wits, South Africa.,Department of Anthropology/Archaeology, Mercyhurst University, Erie, United States.,Department of Applied Forensic Sciences, Mercyhurst University, Erie, United States
| | - Scott A Williams
- Evolutionary Studies Institute, University of the Witwatersrand, Wits, South Africa.,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
| | - Lucas K Delezene
- Evolutionary Studies Institute, University of the Witwatersrand, Wits, South Africa.,Department of Anthropology, University of Arkansas, Fayetteville, United States
| | - Elen M Feuerriegel
- Evolutionary Studies Institute, University of the Witwatersrand, Wits, South Africa.,Department of Anthropology, University of Washington, Seattle, United States
| | - Patrick Randolph-Quinney
- Evolutionary Studies Institute, University of the Witwatersrand, Wits, South Africa.,School of Anatomical Sciences, University of the Witwatersrand Medical School, Johannesburg, South Africa.,School of Forensic and Applied Sciences, University of Central Lancashire, Preston, United Kingdom
| | - Tracy L Kivell
- Evolutionary Studies Institute, University of the Witwatersrand, Wits, South Africa.,School of Anthropology and Conservation, University of Kent, Canterbury, United Kingdom.,Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Myra F Laird
- Evolutionary Studies Institute, University of the Witwatersrand, Wits, South Africa.,Department of Organismal Biology and Anatomy, University of Chicago, Chicago, United States
| | - Gaokgatlhe Tawane
- Evolutionary Studies Institute, University of the Witwatersrand, Wits, South Africa
| | - Jeremy M DeSilva
- Evolutionary Studies Institute, University of the Witwatersrand, Wits, South Africa.,Department of Anthropology, Dartmouth College, Hanover, United States
| | - Shara E Bailey
- 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
| | - Juliet K Brophy
- Evolutionary Studies Institute, University of the Witwatersrand, Wits, South Africa.,Department of Geography and Anthropology, Louisiana State University, Baton Rouge, United States
| | - Marc R Meyer
- Department of Anthropology, Chaffey College, Rancho Cucamonga, United States
| | - Matthew M Skinner
- Evolutionary Studies Institute, University of the Witwatersrand, Wits, South Africa.,School of Anthropology and Conservation, University of Kent, Canterbury, United Kingdom.,Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Matthew W Tocheri
- Department of Anthropology, Lakehead University, Thunder Bay, Canada.,Human Origins Program, Department of Anthropology, National Museum of Natural History, Smithsonian Institution, Washington, United States
| | - Caroline VanSickle
- Evolutionary Studies Institute, University of the Witwatersrand, Wits, South Africa.,Department of Anthropology, University of Wisconsin, Madison, United States.,Department of Anthropology, Bryn Mawr College, Bryn Mawr, United States
| | - Christopher S Walker
- Evolutionary Studies Institute, University of the Witwatersrand, Wits, South Africa.,Department of Evolutionary Anthropology, Duke University, Durham, United States.,Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, United States
| | - Timothy L Campbell
- Department of Anthropology, Texas A&M University, College Station, United States
| | - Brian Kuhn
- Department of Geology, University of Johannesburg, Johannesburg, South Africa
| | - Ashley Kruger
- Evolutionary Studies Institute, University of the Witwatersrand, Wits, South Africa.,School of Geosciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Steven Tucker
- Evolutionary Studies Institute, University of the Witwatersrand, Wits, South Africa
| | - Alia Gurtov
- Evolutionary Studies Institute, University of the Witwatersrand, Wits, South Africa.,Department of Anthropology, University of Wisconsin, Madison, United States
| | - Nompumelelo Hlophe
- Evolutionary Studies Institute, University of the Witwatersrand, Wits, South Africa
| | - Rick Hunter
- Evolutionary Studies Institute, University of the Witwatersrand, Wits, South Africa
| | - Hannah Morris
- Evolutionary Studies Institute, University of the Witwatersrand, Wits, South Africa.,Department of Forestry and Natural Resources, University of Georgia, Athens, United States
| | - Becca Peixotto
- Evolutionary Studies Institute, University of the Witwatersrand, Wits, South Africa.,Department of Anthropology, American University, Washington, United States
| | - Maropeng Ramalepa
- Evolutionary Studies Institute, University of the Witwatersrand, Wits, South Africa
| | - Dirk van Rooyen
- Evolutionary Studies Institute, University of the Witwatersrand, Wits, South Africa
| | - Mathabela Tsikoane
- Evolutionary Studies Institute, University of the Witwatersrand, Wits, South Africa
| | - Pedro Boshoff
- Evolutionary Studies Institute, University of the Witwatersrand, Wits, South Africa
| | - Paul Hgm Dirks
- Geosciences, College of Science and Engineering, James Cook University, Townsville, Australia
| | - Lee R Berger
- Evolutionary Studies Institute, University of the Witwatersrand, Wits, South Africa
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42
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Neufuss J, Humle T, Cremaschi A, Kivell TL. Nut-cracking behaviour in wild-born, rehabilitated bonobos (Pan paniscus): a comprehensive study of hand-preference, hand grips and efficiency. Am J Primatol 2016; 79:1-16. [DOI: 10.1002/ajp.22589] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 08/01/2016] [Accepted: 08/01/2016] [Indexed: 11/11/2022]
Affiliation(s)
- Johanna Neufuss
- Animal Postcranial Evolution Laboratory, Skeletal Biology Research Centre, School of Anthropology and Conservation; University of Kent; Canterbury UK
| | - Tatyana Humle
- Durrell Institute of Conservation and Ecology, School of Anthropology and Conservation; University of Kent; Canterbury UK
| | - Andrea Cremaschi
- School of Mathematics, Statistics and Actuarial Science; University of Kent; UK
| | - Tracy L. Kivell
- Animal Postcranial Evolution Laboratory, Skeletal Biology Research Centre, School of Anthropology and Conservation; University of Kent; Canterbury UK
- Department of Human Evolution; Max Planck Institute for Evolutionary Anthropology; Leipzig Germany
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43
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Stephens NB, Kivell TL, Gross T, Pahr DH, Lazenby RA, Hublin JJ, Hershkovitz I, Skinner MM. Trabecular architecture in the thumb of Pan and Homo: implications for investigating hand use, loading, and hand preference in the fossil record. Am J Phys Anthropol 2016; 161:603-619. [PMID: 27500902 DOI: 10.1002/ajpa.23061] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Revised: 06/14/2016] [Accepted: 07/24/2016] [Indexed: 12/31/2022]
Abstract
OBJECTIVES Humans display an 85-95% cross-cultural right-hand bias in skilled tasks, which is considered a derived behavior because such a high frequency is not reported in wild non-human primates. Handedness is generally considered to be an evolutionary byproduct of selection for manual dexterity and augmented visuo-cognitive capabilities within the context of complex stone tool manufacture/use. Testing this hypothesis requires an understanding of when appreciable levels of right dominant behavior entered the fossil record. Because bone remodels in vivo, skeletal asymmetries are thought to reflect greater mechanical loading on the dominant side, but incomplete preservation of external morphology and ambiguities about past loading environments complicate interpretations. We test if internal trabecular bone is capable of providing additional information by analyzing the thumb of Homo sapiens and Pan. MATERIALS AND METHODS We assess trabecular structure at the distal head and proximal base of paired (left/right) first metacarpals using micro-CT scans of Homo sapiens (n = 14) and Pan (n = 9). Throughout each epiphysis we quantify average and local bone volume fraction (BV/TV), degree of anisotropy (DA), and elastic modulus (E) to address bone volume patterning and directional asymmetry. RESULTS We find a right directional asymmetry in H. sapiens consistent with population-level handedness, but also report a left directional asymmetry in Pan that may be the result of postural and/or locomotor loading. CONCLUSION We conclude that trabecular bone is capable of detecting right/left directional asymmetry, but suggest coupling studies of internal structure with analyses of other skeletal elements and cortical bone prior to applications in the fossil record.
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Affiliation(s)
- Nicholas B Stephens
- 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.,Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, CT2 7NR, United Kingdom
| | - Thomas Gross
- Institute of Lightweight Design and Structural Biomechanics, Vienna University of Technology, A-1060 Vienna, Getreidemarkt 9/BE, Vienna, Austria
| | - Dieter H Pahr
- Institute of Lightweight Design and Structural Biomechanics, Vienna University of Technology, A-1060 Vienna, Getreidemarkt 9/BE, Vienna, Austria
| | - Richard A Lazenby
- Department of Anthropology, University of Northern British Columbia, 3333 University Way, Prince George, BC, Canada, V2N 4Z9
| | - Jean-Jacques Hublin
- Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, Leipzig, 04103, Germany
| | - Israel Hershkovitz
- Department of Anatomy and Anthropology, Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Matthew M Skinner
- Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, Leipzig, 04103, Germany.,Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, CT2 7NR, United Kingdom
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44
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Schoonaert K, D'Août K, Samuel D, Talloen W, Nauwelaerts S, Kivell TL, Aerts P. Gait characteristics and spatio-temporal variables of climbing in bonobos (Pan paniscus). Am J Primatol 2016; 78:1165-1177. [DOI: 10.1002/ajp.22571] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Revised: 05/29/2016] [Accepted: 05/29/2016] [Indexed: 11/11/2022]
Affiliation(s)
- Kirsten Schoonaert
- Laboratory for Functional Morphology; Department of Biology; University of Antwerp; Wilrijk Belgium
| | - Kristiaan D'Août
- Laboratory for Functional Morphology; Department of Biology; University of Antwerp; Wilrijk Belgium
- Institute of Ageing and Chronic Disease; Faculty of Health and Life Sciences; University of Liverpool; Liverpool United Kingdom
- Centre for Research and Conservation (CRC); Antwerp Belgium
| | - Diana Samuel
- Animal Postcranial Evolution (APE) Lab; Skeletal Biology Research Centre; School of Anthropology and Conservation; University of Kent; Canterbury United Kingdom
| | - Willem Talloen
- Janssen Pharmaceutica NV of Johnson & Johnson; Turnhoutseweg; Beerse Belgium
| | - Sandra Nauwelaerts
- Laboratory for Functional Morphology; Department of Biology; University of Antwerp; Wilrijk Belgium
- Centre for Research and Conservation (CRC); Antwerp Belgium
| | - Tracy L. Kivell
- Animal Postcranial Evolution (APE) Lab; Skeletal Biology Research Centre; School of Anthropology and Conservation; University of Kent; Canterbury United Kingdom
| | - Peter Aerts
- Laboratory for Functional Morphology; Department of Biology; University of Antwerp; Wilrijk Belgium
- Laboratory for Biomechanics and Motor Control of Human Movement; Department of Movement and Sports Sciences; University of Ghent; Gent Belgium
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45
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Behringer V, Stevens JMG, Kivell TL, Neufuss J, Boesch C, Hohmann G. Within arm's reach: Measuring forearm length to assess growth patterns in captive bonobos and chimpanzees. Am J Phys Anthropol 2016; 161:37-43. [DOI: 10.1002/ajpa.23004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Revised: 02/02/2016] [Accepted: 04/13/2016] [Indexed: 11/07/2022]
Affiliation(s)
- Verena Behringer
- Department of Primatology; Max Planck Institute for Evolutionary Anthropology; Leipzig Germany
| | - Jeroen M. G. Stevens
- Royal Zoological Society of Antwerp; Centre for Research and Conservation; K. Astridplein Antwerp Belgium
| | - Tracy L. Kivell
- Skeletal Biology Research Centre, Animal Postcranial Evolutionary Lab, School of Anthropology and Conservation, University of Kent; Marlowe Building Canterbury Kent UK
- Department of Human Evolution; Max Planck Institute for Evolutionary Anthropology; Leipzig Germany
| | - Johanna Neufuss
- Skeletal Biology Research Centre, Animal Postcranial Evolutionary Lab, School of Anthropology and Conservation, University of Kent; Marlowe Building Canterbury Kent UK
| | - Christophe Boesch
- Department of Primatology; Max Planck Institute for Evolutionary Anthropology; Leipzig Germany
| | - Gottfried Hohmann
- Department of Primatology; Max Planck Institute for Evolutionary Anthropology; Leipzig Germany
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46
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Kivell TL. A review of trabecular bone functional adaptation: what have we learned from trabecular analyses in extant hominoids and what can we apply to fossils? J Anat 2016; 228:569-94. [PMID: 26879841 DOI: 10.1111/joa.12446] [Citation(s) in RCA: 113] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/04/2016] [Indexed: 12/31/2022] Open
Abstract
Many of the unresolved debates in palaeoanthropology regarding evolution of particular locomotor or manipulative behaviours are founded in differing opinions about the functional significance of the preserved external fossil morphology. However, the plasticity of internal bone morphology, and particularly trabecular bone, allowing it to respond to mechanical loading during life means that it can reveal greater insight into how a bone or joint was used during an individual's lifetime. Analyses of trabecular bone have been commonplace for several decades in a human clinical context. In contrast, the study of trabecular bone as a method for reconstructing joint position, joint loading and ultimately behaviour in extant and fossil non-human primates is comparatively new. Since the initial 2D studies in the late 1970s and 3D analyses in the 1990 s, the utility of trabecular bone to reconstruct behaviour in primates has grown to incorporate experimental studies, expanded taxonomic samples and skeletal elements, and improved methodologies. However, this work, in conjunction with research on humans and non-primate mammals, has also revealed the substantial complexity inherent in making functional inferences from variation in trabecular architecture. This review addresses the current understanding of trabecular bone functional adaptation, how it has been applied to hominoids, as well as other primates and, ultimately, how this can be used to better interpret fossil hominoid and hominin morphology. Because the fossil record constrains us to interpreting function largely from bony morphology alone, and typically from isolated bones, analyses of trabecular structure, ideally in conjunction with that of cortical structure and external morphology, can offer the best resource for reconstructing behaviour in the past.
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Affiliation(s)
- Tracy L Kivell
- Animal Postcranial Evolution Laboratory, Skeletal Biological Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, UK.,Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
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47
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48
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Abstract
For several decades, it was largely assumed that stone tool use and production were abilities limited to the genus Homo. However, growing palaeontological and archaeological evidence, comparative extant primate studies, as well as results from methodological advancements in biomechanics and morphological analyses, have been gradually accumulating and now provide strong support for more advanced manual manipulative abilities and tool-related behaviours in pre-Homo hominins than has been traditionally recognized. Here, I review the fossil evidence related to early hominin dexterity, including the recent discoveries of relatively complete early hominin hand skeletons, and new methodologies that are providing a more holistic interpretation of hand function, and insight into how our early ancestors may have balanced the functional requirements of both arboreal locomotion and tool-related behaviours.
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Affiliation(s)
- Tracy L Kivell
- Animal Postcranial Evolution (APE) Lab, Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Marlowe Building, Canterbury, Kent CT2 7NR, UK Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, Leipzig 04103, Germany
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49
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Kivell TL, Deane AS, Tocheri MW, Orr CM, Schmid P, Hawks J, Berger LR, Churchill SE. The hand of Homo naledi. Nat Commun 2015; 6:8431. [PMID: 26441219 PMCID: PMC4597335 DOI: 10.1038/ncomms9431] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 08/20/2015] [Indexed: 11/09/2022] Open
Abstract
A nearly complete right hand of an adult hominin was recovered from the Rising Star cave system, South Africa. Based on associated hominin material, the bones of this hand are attributed to Homo naledi. This hand reveals a long, robust thumb and derived wrist morphology that is shared with Neandertals and modern humans, and considered adaptive for intensified manual manipulation. However, the finger bones are longer and more curved than in most australopiths, indicating frequent use of the hand during life for strong grasping during locomotor climbing and suspension. These markedly curved digits in combination with an otherwise human-like wrist and palm indicate a significant degree of climbing, despite the derived nature of many aspects of the hand and other regions of the postcranial skeleton in H. naledi. It is unclear to what extent early hominins were adapted to arboreal climbing. Here, the authors show that the nearly complete hand of H. naledi from South Africa has markedly curved digits and otherwise human-like wrist and palm, which indicates the retention of a significant degree of climbing.
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Affiliation(s)
- Tracy L Kivell
- Animal Postcranial Evolution Lab, Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Marlowe Building, Canterbury CT2 7NR, UK.,Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, Leipzig 04103, Germany.,Evolutionary Studies Institute and Centre for Excellence in PalaeoSciences, University of the Witwatersrand, Private Bag 3, Wits 2050, South Africa
| | - Andrew S Deane
- Evolutionary Studies Institute and Centre for Excellence in PalaeoSciences, University of the Witwatersrand, Private Bag 3, Wits 2050, South Africa.,Department of Anatomy and Neurobiology, College of Medicine, University of Kentucky, MN 224 UK Medical Centre, Lexington, Kentucky 40536-0098, USA
| | - Matthew W Tocheri
- Department of Anthropology, Lakehead University, Thunder Bay Ontario, Canada P7K 1L8.,Human Origins Program, Department of Anthropology, National Museum of Natural History, Smithsonian Institution, Washington DC 20560, USA
| | - Caley M Orr
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
| | - Peter Schmid
- Evolutionary Studies Institute and Centre for Excellence in PalaeoSciences, University of the Witwatersrand, Private Bag 3, Wits 2050, South Africa.,Anthropological Institute and Museum, University of Zuerich, Winterthurerstrasse 190, Zuerich CH-8057, Switzerland
| | - John Hawks
- Evolutionary Studies Institute and Centre for Excellence in PalaeoSciences, University of the Witwatersrand, Private Bag 3, Wits 2050, South Africa.,Department of Anthropology, University of Wisconsin-Madison, Madison, Wisconsin 53593, USA
| | - Lee R Berger
- Evolutionary Studies Institute and Centre for Excellence in PalaeoSciences, University of the Witwatersrand, Private Bag 3, Wits 2050, South Africa
| | - Steven E Churchill
- Evolutionary Studies Institute and Centre for Excellence in PalaeoSciences, University of the Witwatersrand, Private Bag 3, Wits 2050, South Africa.,Department of Evolutionary Anthropology, Duke University, Box 90383, Durham, North Carolina 27708-9976, USA
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50
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Berger LR, Hawks J, de Ruiter DJ, Churchill SE, Schmid P, Delezene LK, Kivell TL, Garvin HM, Williams SA, DeSilva JM, Skinner MM, Musiba CM, Cameron N, Holliday TW, Harcourt-Smith W, Ackermann RR, Bastir M, Bogin B, Bolter D, Brophy J, Cofran ZD, Congdon KA, Deane AS, Dembo M, Drapeau M, Elliott MC, Feuerriegel EM, Garcia-Martinez D, Green DJ, Gurtov A, Irish JD, Kruger A, Laird MF, Marchi D, Meyer MR, Nalla S, Negash EW, Orr CM, Radovcic D, Schroeder L, Scott JE, Throckmorton Z, Tocheri MW, VanSickle C, Walker CS, Wei P, Zipfel B. Homo naledi, a new species of the genus Homo from the Dinaledi Chamber, South Africa. eLife 2015; 4:e09560. [PMID: 26354291 PMCID: PMC4559886 DOI: 10.7554/elife.09560] [Citation(s) in RCA: 198] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 08/04/2015] [Indexed: 11/13/2022] Open
Abstract
Homo naledi is a previously-unknown species of extinct hominin discovered within the Dinaledi Chamber of the Rising Star cave system, Cradle of Humankind, South Africa. This species is characterized by body mass and stature similar to small-bodied human populations but a small endocranial volume similar to australopiths. Cranial morphology of H. naledi is unique, but most similar to early Homo species including Homo erectus, Homo habilis or Homo rudolfensis. While primitive, the dentition is generally small and simple in occlusal morphology. H. naledi has humanlike manipulatory adaptations of the hand and wrist. It also exhibits a humanlike foot and lower limb. These humanlike aspects are contrasted in the postcrania with a more primitive or australopith-like trunk, shoulder, pelvis and proximal femur. Representing at least 15 individuals with most skeletal elements repeated multiple times, this is the largest assemblage of a single species of hominins yet discovered in Africa.
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Affiliation(s)
- Lee R Berger
- Evolutionary Studies Institute and Centre of Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
- School of Geosciences, University of the Witwatersrand, Johannesburg, South Africa
| | - John Hawks
- Evolutionary Studies Institute and Centre of Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
- Department of Anthropology, University of Wisconsin-Madison, Madison, United States
| | - Darryl J de Ruiter
- Evolutionary Studies Institute and Centre of Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
- Department of Anthropology, Texas A&M University, College Station, United States
| | - Steven E Churchill
- Evolutionary Studies Institute and Centre of Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
- Department of Evolutionary Anthropology, Duke University, Durham, United States
| | - Peter Schmid
- Evolutionary Studies Institute and Centre of Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
- Anthropological Institute and Museum, University of Zurich, Zurich, Switzerland
| | - Lucas K Delezene
- Evolutionary Studies Institute and Centre of Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
- Department of Anthropology, University of Arkansas, Fayetteville, United States
| | - Tracy L Kivell
- Evolutionary Studies Institute and Centre of Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
- School of Anthropology and Conservation, University of Kent, Canterbury, United Kingdom
- Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Heather M Garvin
- Evolutionary Studies Institute and Centre of Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
- Department of Anthropology/Archaeology and Department of Applied Forensic Sciences, Mercyhurst University, Erie, United States
| | - Scott A Williams
- Evolutionary Studies Institute and Centre of Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
- 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
- Evolutionary Studies Institute and Centre of Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
- Department of Anthropology, Dartmouth College, Hanover, United States
| | - Matthew M Skinner
- Evolutionary Studies Institute and Centre of Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
- School of Anthropology and Conservation, University of Kent, Canterbury, United Kingdom
- Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Charles M Musiba
- Evolutionary Studies Institute and Centre of Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
- Department of Anthropology, University of Colorado Denver, Denver, United States
| | - Noel Cameron
- Evolutionary Studies Institute and Centre of Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, United Kingdom
| | - Trenton W Holliday
- Evolutionary Studies Institute and Centre of Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
- Department of Anthropology, Tulane University, New Orleans, United States
| | - William Harcourt-Smith
- Evolutionary Studies Institute and Centre of Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
- Department of Anthropology, Lehman College, Bronx, United States
- Division of Paleontology, American Museum of Natural History, New York, United States
| | - Rebecca R Ackermann
- Department of Archaeology, University of Cape Town, Rondebosch, South Africa
| | - Markus Bastir
- Evolutionary Studies Institute and Centre of Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
- Paleoanthropology Group, Museo Nacional de Ciencias Naturales, Madrid, Spain
| | - Barry Bogin
- Evolutionary Studies Institute and Centre of Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, United Kingdom
| | - Debra Bolter
- Evolutionary Studies Institute and Centre of Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
- Department of Anthropology, Modesto Junior College, Modesto, United States
| | - Juliet Brophy
- Evolutionary Studies Institute and Centre of Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
- Department of Geography and Anthropology, Louisiana State University, Baton Rouge, United States
| | - Zachary D Cofran
- Evolutionary Studies Institute and Centre of Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
- School of Humanities and Social Sciences, Nazarbayev University, Astana, Kazakhstan
| | - Kimberly A Congdon
- Evolutionary Studies Institute and Centre of Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
- Department of Pathology and Anatomical Sciences, University of Missouri, Columbia, United States
| | - Andrew S Deane
- Evolutionary Studies Institute and Centre of Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
- Department of Anatomy and Neurobiology, University of Kentucky College of Medicine, Lexington, United States
| | - Mana Dembo
- Evolutionary Studies Institute and Centre of Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
- Human Evolutionary Studies Program and Department of Archaeology, Simon Fraser University, Burnaby, Canada
| | - Michelle Drapeau
- Department d'Anthropologie, Université de Montréal, Montréal, Canada
| | - Marina C Elliott
- Evolutionary Studies Institute and Centre of Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
- Human Evolutionary Studies Program and Department of Archaeology, Simon Fraser University, Burnaby, Canada
| | - Elen M Feuerriegel
- Evolutionary Studies Institute and Centre of Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
- School of Archaeology and Anthropology, Australian National University, Canberra, Australia
| | - Daniel Garcia-Martinez
- Evolutionary Studies Institute and Centre of Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
- Paleoanthropology Group, Museo Nacional de Ciencias Naturales, Madrid, Spain
- Faculty of Sciences, Biology Department, Universidad Autònoma de Madrid, Madrid, Spain
| | - David J Green
- Evolutionary Studies Institute and Centre of Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
- Department of Anatomy, Midwestern University, Downers Grove, United States
| | - Alia Gurtov
- Evolutionary Studies Institute and Centre of Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
- Department of Anthropology, University of Wisconsin-Madison, Madison, United States
| | - Joel D Irish
- Evolutionary Studies Institute and Centre of Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
- Research Centre in Evolutionary Anthropology and Palaeoecology, Liverpool John Moores University, Liverpool, United Kingdom
| | - Ashley Kruger
- Evolutionary Studies Institute and Centre of Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Myra F Laird
- Evolutionary Studies Institute and Centre of Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
- 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
| | - Damiano Marchi
- Evolutionary Studies Institute and Centre of Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
- Department of Biology, University of Pisa, Pisa, Italy
| | - Marc R Meyer
- Evolutionary Studies Institute and Centre of Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
- Department of Anthropology, Chaffey College, Rancho Cucamonga, United States
| | - Shahed Nalla
- Evolutionary Studies Institute and Centre of Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
- Department of Human Anatomy and Physiology, University of Johannesburg, Johannesburg, South Africa
| | - Enquye W Negash
- Evolutionary Studies Institute and Centre of Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
- Center for the Advanced Study of Human Paleobiology, George Washington University, Washington, United States
| | - Caley M Orr
- Evolutionary Studies Institute and Centre of Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, United States
| | - Davorka Radovcic
- Evolutionary Studies Institute and Centre of Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
- Department of Geology and Paleontology, Croatian Natural History Museum, Zagreb, Croatia
| | - Lauren Schroeder
- Evolutionary Studies Institute and Centre of Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
- Department of Archaeology, University of Cape Town, Rondebosch, South Africa
| | - Jill E Scott
- Evolutionary Studies Institute and Centre of Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
- Department of Anthropology, University of Iowa, Iowa City, United States
| | - Zachary Throckmorton
- Evolutionary Studies Institute and Centre of Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
- Department of Anatomy, DeBusk College of Osteopathic Medicine, Lincoln Memorial University, Harrogate, United States
| | - Matthew W Tocheri
- Human Origins Program, Department of Anthropology, National Museum of Natural History, Smithsonian Institution, Washington, United States
- Department of Anthropology, Lakehead University, Thunder Bay, Canada
| | - Caroline VanSickle
- Evolutionary Studies Institute and Centre of Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
- Department of Anthropology, University of Wisconsin-Madison, Madison, United States
- Department of Gender and Women's Studies, University of Wisconsin-Madison, Madison, United States
| | - Christopher S Walker
- Evolutionary Studies Institute and Centre of Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
- Department of Evolutionary Anthropology, Duke University, Durham, United States
| | - Pianpian Wei
- Evolutionary Studies Institute and Centre of Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
- Department of Paleoanthropology, Institute of Vertebrate Paleontology and Paleoanthropology, Beijing, China
| | - Bernhard Zipfel
- Evolutionary Studies Institute and Centre of Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa
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