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Woldt KM, Pratt RB, Statham MJ, Barthman-Thompson LM, Sustaita D. Comparative skeletal anatomy of salt marsh and western harvest mice in relation to locomotor ecology. J Anat 2024; 245:289-302. [PMID: 38613221 PMCID: PMC11259749 DOI: 10.1111/joa.14047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 02/29/2024] [Accepted: 03/27/2024] [Indexed: 04/14/2024] Open
Abstract
The salt marsh harvest mouse (Reithrodontomys raviventris) is an endangered species, endemic to the San Francisco Bay Estuary, that co-occurs with the more broadly distributed species, the western harvest mouse (Reithrodontomys megalotis). Despite their considerable external morphological similarities, the northern subspecies of salt marsh harvest mice have relatively longer and thicker tails than do western harvest mice, which may be related to their abilities to climb emergent marsh vegetation to avoid tidal inundation. We used micro-CT to compare post-cranial skeletal anatomy between the salt marsh and western harvest mouse, to examine whether the salt marsh harvest mouse's restriction to brackish marshes is associated with skeletal adaptations for scansorial locomotion. We found that salt marsh harvest mice exhibited a deeper 3rd caudal vertebra, a more caudally located longest tail vertebra, craniocaudally longer tail vertebrae, and a longer digit III proximal phalanx than western harvest mice. These phalangeal and vertebral characteristics are known to decrease body rotations during climbing, increase contact with substrates, and decrease fall susceptibility in arboreal mammals, suggesting that the salt marsh harvest mouse may be morphologically specialized for scansorial locomotion, adaptive for its dynamic wetland environment.
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Affiliation(s)
- Kelsey M Woldt
- Department of Biological Sciences, California State University, San Marcos, San Marcos, California, USA
- Rocks Biological Consulting, San Diego, California, USA
| | - R Brandon Pratt
- Department of Biology, California State University, Bakersfield, Bakersfield, California, USA
| | - Mark J Statham
- Veterinary Genetics Laboratory, University of California, Davis, Davis, California, USA
| | - Laureen M Barthman-Thompson
- California Department of Fish & Wildlife, Suisun Marsh Monitoring & Compliance Unit, Stockton, California, USA
| | - Diego Sustaita
- Department of Biological Sciences, California State University, San Marcos, San Marcos, California, USA
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2
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MacLean KFE, Langenderfer JE, Dickerson CR. A comparative probabilistic analysis of human and chimpanzee rotator cuff functional capacity. J Anat 2023; 243:431-447. [PMID: 37186281 PMCID: PMC10439372 DOI: 10.1111/joa.13882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 04/10/2023] [Accepted: 04/11/2023] [Indexed: 05/17/2023] Open
Abstract
Computational musculoskeletal modeling represents a valuable approach to examining biological systems in physical anthropology. Probabilistic modeling builds on computational musculoskeletal models by associating mathematical distributions of specific musculoskeletal features within known ranges of biological variability with functional outcomes. The purpose of this study was to determine if overlap in rotator cuff muscle force predictions would occur between species during the performance of an evolutionarily relevant horizontal bimanual arm suspension task. This necessitated creating novel probabilistic models of the human and chimpanzee glenohumeral joint through augmentation of previously published deterministic models. Glenohumeral musculoskeletal features of anthropological interest were probabilistically modeled to produce distributions of predicted human and chimpanzee rotator cuff muscle force that were representative of the specific anatomical manipulations. Musculoskeletal features modeled probabilistically included rotator cuff origins and deltoid insertion, glenoid inclination, and joint stability. Predicted human rotator cuff muscle force distributions were mostly limited to alternating between infraspinatus and teres minor, with both 100% and 0% muscle force predicted for both muscles. The chimpanzee model predicted low-to-moderate muscle force across all rotator cuff muscles. Rotator cuff muscle force predictions were most sensitive to changes of muscle origins and insertions. Results indicate that functional rotator cuff overlap is unlikely between chimpanzees and humans without greater modifications of the glenohumeral musculoskeletal phenotypes. The results also highlight the low efficacy of the human upper extremity in overhead, weight-bearing tasks, and propensity for rotator cuff injury.
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Skedros JG, Cronin JT, Dayton MR, Bloebaum RD, Bachus KN. Exploration of the synergistic role of cortical thickness asymmetry ("Trabecular Eccentricity" concept) in reducing fracture risk in the human femoral neck and a control bone (Artiodactyl Calcaneus). J Theor Biol 2023; 567:111495. [PMID: 37068584 DOI: 10.1016/j.jtbi.2023.111495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 03/24/2023] [Accepted: 04/10/2023] [Indexed: 04/19/2023]
Abstract
The mechanobiology of the human femoral neck is a focus of research for many reasons including studies that aim to curb age-related bone loss that contributes to a near-exponential rate of hip fractures. Many believe that the femoral neck is often loaded in rather simple bending, which causes net tension stress in the upper (superior) femoral neck and net compression stress in its inferior aspect ("T/C paradigm"). This T/C loading regime lacks in vivo proof. The "C/C paradigm" is a plausible alternative simplified load history that is characterized by a gradient of net compression across the entire femoral neck; action of the gluteus medius and external rotators of the hip are important in this context. It is unclear which paradigm is at play in natural loading due to lack of in vivo bone strain data and deficiencies in understanding mechanisms and manifestations of bone adaptation in tension vs. compression. For these reasons, studies of the femoral neck would benefit from being compared to a 'control bone' that has been proven, by strain data, to be habitually loaded in bending. The artiodactyl (sheep and deer) calcaneus model has been shown to be a very suitable control in this context. However, the application of this control in understanding the load history of the femoral neck has only been attempted in two prior studies, which did not examine the interplay between cortical and trabecular bone, or potential load-sharing influences of tendons and ligaments. Our first goal is to compare fracture risk factors of the femoral neck in both paradigms. Our second goal is to compare and contrast the deer calcaneus to the human femoral neck in terms of fracture risk factors in the T/C paradigm (the C/C paradigm is not applicable in the artiodactyl calcaneus due to its highly constrained loading). Our third goal explores interplay between dorsal/compression and plantar/tension regions of the deer calcaneus and the load-sharing roles of a nearby ligament and tendon, with insights for translation to the femoral neck. These goals were achieved by employing the analytical model of Fox and Keaveny (J. Theoretical Biology 2001, 2003) that estimates fracture risk factors of the femoral neck. This model focuses on biomechanical advantages of the asymmetric distribution of cortical bone in the direction of habitual loading. The cortical thickness asymmetry of the femoral neck (thin superior cortex, thick inferior cortex) reflects the superior-inferior placement of trabecular bone (i.e., "trabecular eccentricity," TE). TE helps the femoral neck adapt to typical stresses and strains through load-sharing between superior and inferior cortices. Our goals were evaluated in the context of TE. Results showed the C/C paradigm has lower risk factors for the superior cortex and for the overall femoral neck, which is clinically relevant. TE analyses of the deer calcaneus revealed important synergism in load-sharing between the plantar/tension cortex and adjacent ligament/tendon, which challenges conventional understanding of how this control bone achieves functional adaptation. Comparisons with the control bone also exposed important deficiencies in current understanding of human femoral neck loading and its potential histocompositional adaptations.
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Affiliation(s)
- John G Skedros
- University of Utah, Department of Orthopaedics, Salt Lake City, UT, USA; Research Service, Veterans Affairs Medical Center, Salt Lake City, UT, USA.
| | - John T Cronin
- University of Utah, Department of Orthopaedics, Salt Lake City, UT, USA
| | - Michael R Dayton
- University of Colorado, Department of Orthopedics, Aurora, CO, USA
| | - Roy D Bloebaum
- University of Utah, Department of Orthopaedics, Salt Lake City, UT, USA; Research Service, Veterans Affairs Medical Center, Salt Lake City, UT, USA
| | - Kent N Bachus
- University of Utah, Department of Orthopaedics, Salt Lake City, UT, USA; Research Service, Veterans Affairs Medical Center, Salt Lake City, UT, USA
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4
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Stamos PA, Alemseged Z. Hominin locomotion and evolution in the Late Miocene to Late Pliocene. J Hum Evol 2023; 178:103332. [PMID: 36947894 DOI: 10.1016/j.jhevol.2023.103332] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 01/26/2023] [Accepted: 01/27/2023] [Indexed: 03/24/2023]
Abstract
In this review, we present on the evolution of the locomotor adaptation of hominins in the Late Miocene to Late Pliocene, with emphasis on some of the prominent advances and debates that have occurred over the past fifty years. We start with the challenging issue of defining hominin locomotor grades that are currently used liberally and offer our own working definitions of facultative, habitual, and obligate bipedalism. We then discuss the nature of the Pan-Homo last common ancestor and characterize the locomotor adaptation of Sahelanthropus, Orrorin, and Ardipithecus-often referred to as facultative bipeds-and examine the debates on the extent of bipedality and arboreality in these taxa. Moreover, the question of Middle Pliocene hominin locomotor diversity is addressed based on information derived from the 'Little Foot' specimen from Sterkfontein, footprints from Laetoli, and the Burtele Foot in Ethiopia. Our review suggests that the most convincing evidence for locomotor diversity comes from Burtele, whereas the evidence from Sterkfontein and Laetoli is unconvincing and equivocal, respectively. Finally, we address the decades old issue of the significance of arboreality in the otherwise habitual biped, Australopithecus, with emphasis on Australopithecus afarensis and its implications for the paleobiology of these creatures. We conclude that many of the apelike features encountered, mostly in the upper part of the Australopithecus skeleton, were retained for their significance in climbing. Approaches that have investigated character plasticity and those exploring internal bone structure have shown that the shoulder and limbs in Au. afarensis and Australopithecus africanus were involved in arboreal activities that are thought to be key for feeding, nesting, and predator avoidance. We conclude that many of the so-called retained ape-like features persisted due to stabilizing selection, that early hominins engaged in a considerable amount of arboreality even after Australopithecus had become a habitual biped, and arboreality only ceased to be an important component of hominin locomotor behavior after the emergence of Homo erectus.
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Affiliation(s)
- Peter A Stamos
- Department of Organismal Biology & Anatomy, The University of Chicago, Anatomy Bldg 201, 1027 E 57th Street, Chicago, IL 60637, USA
| | - Zeresenay Alemseged
- Department of Organismal Biology & Anatomy, The University of Chicago, Anatomy Bldg 201, 1027 E 57th Street, Chicago, IL 60637, USA.
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5
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Young M, Richard D, Grabowski M, Auerbach BM, de Bakker BS, Hagoort J, Muthuirulan P, Kharkar V, Kurki HK, Betti L, Birkenstock L, Lewton KL, Capellini TD. The developmental impacts of natural selection on human pelvic morphology. SCIENCE ADVANCES 2022; 8:eabq4884. [PMID: 35977020 PMCID: PMC9385149 DOI: 10.1126/sciadv.abq4884] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Accepted: 06/29/2022] [Indexed: 06/15/2023]
Abstract
Evolutionary responses to selection for bipedalism and childbirth have shaped the human pelvis, a structure that differs substantially from that in apes. Morphology related to these factors is present by birth, yet the developmental-genetic mechanisms governing pelvic shape remain largely unknown. Here, we pinpoint and characterize a key gestational window when human-specific pelvic morphology becomes recognizable, as the ilium and the entire pelvis acquire traits essential for human walking and birth. We next use functional genomics to molecularly characterize chondrocytes from different pelvic subelements during this window to reveal their developmental-genetic architectures. We then find notable evidence of ancient selection and genetic constraint on regulatory sequences involved in ilium expansion and growth, findings complemented by our phenotypic analyses showing that variation in iliac traits is reduced in humans compared to African apes. Our datasets provide important resources for musculoskeletal biology and begin to elucidate developmental mechanisms that shape human-specific morphology.
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Affiliation(s)
- Mariel Young
- Human Evolutionary Biology, Harvard University, Cambridge, MA, USA
| | - Daniel Richard
- Human Evolutionary Biology, Harvard University, Cambridge, MA, USA
| | - Mark Grabowski
- Research Centre in Evolutionary Anthropology and Palaeoecology, Liverpool John Moores University, Liverpool L3 3AF, UK
- Department of Biosciences, Centre for Ecological and Evolutionary Synthesis (CEES), University of Oslo, Oslo, Norway
| | - Benjamin M. Auerbach
- Department of Anthropology, The University of Tennessee, Knoxville, TN, USA
- Department of Ecology and Evolutionary Biology, The University of Tennessee, Knoxville, TN, USA
| | - Bernadette S. de Bakker
- Department of Obstetrics and Gynecology, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, Amsterdam, Netherlands
- Amsterdam Reproduction and Development Research Institute, Amsterdam, Netherlands
| | - Jaco Hagoort
- Department of Medical Biology, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, Amsterdam, Netherlands
| | | | - Vismaya Kharkar
- Human Evolutionary Biology, Harvard University, Cambridge, MA, USA
| | - Helen K. Kurki
- Department of Anthropology, University of Victoria, STN CSC, Victoria, BC V8W 2Y2, Canada
| | - Lia Betti
- School of Life and Health Sciences, University of Roehampton, London SW15 4JD, UK
| | | | - Kristi L. Lewton
- Department of Integrative Anatomical Sciences, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Terence D. Capellini
- Human Evolutionary Biology, Harvard University, Cambridge, MA, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
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6
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Komza K, Viola B, Netten T, Schroeder L. Morphological integration in the hominid midfoot. J Hum Evol 2022; 170:103231. [PMID: 35940157 DOI: 10.1016/j.jhevol.2022.103231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 06/27/2022] [Accepted: 06/29/2022] [Indexed: 10/15/2022]
Abstract
The calculation of morphological integration across living apes and humans may provide important insights into the potential influence of integration on evolutionary trajectories in the hominid lineage. Here, we quantify magnitudes of morphological integration among and within elements of the midfoot in great apes and humans to examine the link between locomotor differences and trait covariance. We test the hypothesis that the medial elements of the great ape foot are less morphologically integrated with one another compared to humans based on their abducted halluces, and aim to determine how adaptations for midfoot mobility/stiffness and locomotor specialization influence magnitudes of morphological integration. The study sample is composed of all cuneiforms, the navicular, the cuboid, and metatarsals 1-5 of Homo sapiens (n = 80), Pan troglodytes (n = 63), Gorilla gorilla (n = 39), and Pongo sp. (n = 41). Morphological integration was quantified using the integration coefficient of variation of interlandmark distances organized into sets of a priori-defined modules. Magnitudes of integration across these modules were then compared against sets of random traits from the whole midfoot. Results show that all nonhuman apes have less integrated medial elements, whereas humans have highly integrated medial elements, suggesting a link between hallucal abduction and reduced levels of morphological integration. However, we find considerable variation in magnitudes of morphological integration across metatarsals 2-5, the intermediate and lateral cuneiform, the cuboid, and navicular, emphasizing the influence of functional and nonfunctional factors in magnitudes of integration. Lastly, we find that humans and orangutans show the lowest overall magnitudes of integration in the midfoot, which may be related to their highly specialized functions, and suggest a link between strong diversifying selection and reduced magnitudes of morphological integration.
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Affiliation(s)
- Klara Komza
- Department of Anthropology, University of Toronto, Toronto, ON, M5S 2S2, Canada.
| | - Bence Viola
- Department of Anthropology, University of Toronto, Toronto, ON, M5S 2S2, Canada
| | - Teagan Netten
- Department of Anthropology, University of Toronto, Toronto, ON, M5S 2S2, Canada
| | - Lauren Schroeder
- Department of Anthropology, University of Toronto Mississauga, Mississauga, ON, L5L 1C6, Canada; Human Evolution Research Institute, Department of Anthropology, University of Cape Town, Rondebosch, 7701, South Africa
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7
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Marino FE, Sibson BE, Lieberman DE. The evolution of human fatigue resistance. J Comp Physiol B 2022; 192:411-422. [PMID: 35552490 PMCID: PMC9197885 DOI: 10.1007/s00360-022-01439-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 03/28/2022] [Accepted: 04/20/2022] [Indexed: 11/26/2022]
Abstract
Humans differ from African great apes in numerous respects, but the chief initial difference setting hominins on their unique evolutionary trajectory was habitual bipedalism. The two most widely supported selective forces for this adaptation are increased efficiency of locomotion and improved ability to feed in upright contexts. By 4 million years ago, hominins had evolved the ability to walk long distances but extreme selection for endurance capabilities likely occurred later in the genus Homo to help them forage, power scavenge and persistence hunt in hot, arid conditions. In this review we explore the hypothesis that to be effective long-distance walkers and especially runners, there would also have been a strong selective benefit among Homo to resist fatigue. Our hypothesis is that since fatigue is an important factor that limits the ability to perform endurance-based activities, fatigue resistance was likely an important target for selection during human evolution for improved endurance capabilities. We review the trade-offs between strength, power, and stamina in apes and Homo and discuss three biological systems that we hypothesize humans evolved adaptations for fatigue resistance: neurological, metabolic and thermoregulatory. We conclude that the evolution of endurance at the cost of strength and power likely also involved the evolution of mechanisms to resist fatigue.
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Affiliation(s)
- Frank E Marino
- School of Allied Health, Exercise and Sport Science, Charles Sturt University, Bathurst, NSW, 2795, Australia.
| | - Benjamin E Sibson
- Department of Human Evolutionary Biology, Harvard University, 11 Divinity Ave, Cambridge, MA, 02138, USA
| | - Daniel E Lieberman
- Department of Human Evolutionary Biology, Harvard University, 11 Divinity Ave, Cambridge, MA, 02138, USA
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8
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Calcar femorale variation in extant and fossil hominids: Implications for identifying bipedal locomotion in fossil hominins. J Hum Evol 2022; 167:103183. [DOI: 10.1016/j.jhevol.2022.103183] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 03/04/2022] [Accepted: 03/10/2022] [Indexed: 11/21/2022]
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9
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Cazenave M, Oettlé A, Pickering TR, Heaton JL, Nakatsukasa M, Francis Thackeray J, Hoffman J, Macchiarelli R. Trabecular organization of the proximal femur in Paranthropus robustus: Implications for the assessment of its hip joint loading conditions. J Hum Evol 2021; 153:102964. [PMID: 33713985 DOI: 10.1016/j.jhevol.2021.102964] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 01/28/2021] [Accepted: 01/28/2021] [Indexed: 11/19/2022]
Abstract
Reconstruction of the locomotor repertoire of the australopiths (Australopithecus and Paranthropus) has progressively integrated information from the mechanosensitive internal structure of the appendicular skeleton. Recent investigations showed that the arrangement of the trabecular network at the femoral head center is biomechanically compatible with the pattern of cortical bone distribution across the neck, both suggesting a full commitment to bipedalism in australopiths, but associated with a slightly altered gait kinematics compared to Homo involving more lateral deviation of the body center of mass over the stance limb. To provide a global picture in Paranthropus robustus of the trabecular architecture of the proximal femur across the head, neck and greater trochanter compartments, we applied techniques of virtual imaging to the variably preserved Early Pleistocene specimens SK 82, SK 97, SK 3121, SKW 19 and SWT1/LB-2 from the cave site of Swartkrans, South Africa. We also assessed the coherence between the structural signals from the center of the head and those from the trabecular network of the inferolateral portion of the head and the inferior margin of the neck, sampling the so-called vertical bundle, which in humans represents the principal compressive system of the joint. Our analyses show a functionally related trabecular organization in Pa. robustus that closely resembles the extant human condition, but which also includes some specificities in local textural arrangement. The network of the inferolateral portion of the head shows a humanlike degree of anisotropy and a bone volume fraction intermediate between the extant human and the African ape patterns. These results suggest slight differences in gait kinematics between Pa. robustus and extant humans. The neck portion of the vertical bundle revealed a less biomechanically sensitive signal. Future investigations on the australopith hip joint loading environment should more carefully investigate the trabecular structure of the trochanteric region and possible structural covariation between cortical bone distribution across the neck and site-specific trabecular properties of the arcuate bundle.
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Affiliation(s)
- Marine Cazenave
- Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, UK.
| | - Anna Oettlé
- Department of Anatomy and Histology, Sefako Makgatho Health Sciences University, Ga-Rankuwa, Pretoria, South Africa
| | - Travis Rayne Pickering
- Department of Anthropology, University of Wisconsin, Madison, USA; Evolutionary Studies Institute and School of Geosciences, University of the Witwatersrand, Johannesburg, South Africa; Plio-Pleistocene Palaeontology Section, Department of Vertebrates, Ditsong National Museum of Natural History (Transvaal Museum), Pretoria, South Africa
| | - Jason L Heaton
- Department of Biology, Birmingham-Southern College, Birmingham, USA; Evolutionary Studies Institute and School of Geosciences, University of the Witwatersrand, Johannesburg, South Africa; Plio-Pleistocene Palaeontology Section, Department of Vertebrates, Ditsong National Museum of Natural History (Transvaal Museum), Pretoria, South Africa
| | - Masato Nakatsukasa
- Laboratory of Physical Anthropology, Department of Zoology, Graduate School of Science, Kyoto University, Kyoto, Japan
| | - J Francis Thackeray
- Evolutionary Studies Institute and School of Geosciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Jakobus Hoffman
- South African Nuclear Energy Corporation SOC Ltd., Pelindaba, South Africa
| | - Roberto Macchiarelli
- Département Homme & Environnement, UMR 7194 CNRS, Muséum national d'Histoire naturelle, 75116, Paris, France; Unité de Formation Géosciences, Université de Poitiers, Poitiers, France
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10
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Spear JK, Williams SA. Mosaic patterns of homoplasy accompany the parallel evolution of suspensory adaptations in the forelimb of tree sloths (Folivora: Xenarthra). Zool J Linn Soc 2020. [DOI: 10.1093/zoolinnean/zlaa154] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Abstract
We examine how derived functional signal and phylogenetic inheritance interact in the forelimb of tree sloths, to understand the relative contribution of each in the evolution of a novel morphobehavioural suite. Molecular and craniodental data demonstrate that extant tree sloths evolved suspensory behaviours and associated morphologies from a non-suspensory ancestor independently of one another, making them a useful model system. We find that convergence in univariate traits is expressed mosaically, although the signal is largely functional. Three-dimensional analyses suggest there is greater conservatism of gross morphology in more proximal bones than in more distal elements. Convergence in some univariate scapular traits is independent of the gross morphology of the scapula itself, demonstrating that functionally relevant morphologies were mapped on to a more conserved scapular shape. Our results suggest that morphological homoplasy is expressed in a mosaic manner. The relationship between homoplasy and trait integration may be more nuanced than previously thought, even within a single adaptive system.
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Affiliation(s)
- Jeffrey K Spear
- Center for the Study of Human Origins & Department of Anthropology, New York University, New York, USA
- New York Consortium in Evolutionary Primatology, New York, USA
| | - Scott A Williams
- Center for the Study of Human Origins & Department of Anthropology, New York University, New York, USA
- New York Consortium in Evolutionary Primatology, New York, USA
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11
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A genotype:phenotype approach to testing taxonomic hypotheses in hominids. Naturwissenschaften 2020; 107:40. [PMID: 32870408 DOI: 10.1007/s00114-020-01696-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 04/20/2020] [Accepted: 08/19/2020] [Indexed: 10/23/2022]
Abstract
Paleontology has long relied on assumptions about the genetic and developmental influences on skeletal variation. The last few decades of developmental genetics have elucidated the genetic pathways involved in making teeth and patterning the dentition. Quantitative genetic analyses have refined this genotype:phenotype map even more, especially for primates. We now have the ability to define dental traits with a fair degree of fidelity to the underlying genetic architecture; for example, the molar module component (MMC) and the premolar-molar module (PMM) that have been defined through quantitative genetic analyses. We leverage an extensive dataset of extant and extinct hominoid dental variation to explore how these two genetically patterned phenotypes have evolved through time. We assess MMC and PMM to test the hypothesis that these two traits reveal a more biologically informed taxonomy at the genus and species levels than do more traditional measurements. Our results indicate that MMC values for hominids fall into two categories and that Homo is derived compared with earlier taxa. We find a more variable, species-level pattern for PMM. These results, in combination with previous research, demonstrate that MMC reflects the phenotypic output of a more evolutionarily stable, or phylogenetically congruent, genetic mechanism, and PMM is a reflection of a more evolutionarily labile mechanism. These results suggest that the human lineage since the split with chimpanzees may not represent as much genus-level variation as has been inferred from traits whose etiologies are not understood.
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12
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Machnicki AL, Reno PL. Great apes and humans evolved from a long-backed ancestor. J Hum Evol 2020; 144:102791. [DOI: 10.1016/j.jhevol.2020.102791] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 03/20/2020] [Accepted: 03/23/2020] [Indexed: 12/20/2022]
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13
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Cortical bone distribution in the femoral neck of Paranthropus robustus. J Hum Evol 2019; 135:102666. [DOI: 10.1016/j.jhevol.2019.102666] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2018] [Revised: 08/20/2019] [Accepted: 08/20/2019] [Indexed: 02/07/2023]
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14
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The hominid ilium is shaped by a synapomorphic growth mechanism that is unique within primates. Proc Natl Acad Sci U S A 2019; 116:13915-13920. [PMID: 31235562 DOI: 10.1073/pnas.1905242116] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The human ilium is significantly shorter and broader than those of all other primates. In addition, it exhibits an anterior inferior iliac spine (AIIS) that emerges via a secondary center of ossification, which is unique to hominids (i.e., all taxa related to the human clade following their phyletic separation from the African apes). Here, we track the ontogeny of human and other primate ossa coxae. The human pattern is unique, from anlage to adulthood, and fusion of its AIIS is the capstone event in a repositioning of the anterior gluteals that maximizes control of pelvic drop during upright walking. It is therefore a hominid synapomorphy that can be used to assess the presence and age of bipedal locomotion in extinct taxa.
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15
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Monson TA, Boisserie J, Brasil MF, Clay SM, Dvoretzky R, Ravindramurthy S, Schmitt CA, Souron A, Takenaka R, Ungar PS, Yoo S, Zhou M, Zuercher ME, Hlusko LJ. Evidence of strong stabilizing effects on the evolution of boreoeutherian (Mammalia) dental proportions. Ecol Evol 2019; 9:7597-7612. [PMID: 31346425 PMCID: PMC6635932 DOI: 10.1002/ece3.5309] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 04/25/2019] [Accepted: 04/28/2019] [Indexed: 11/28/2022] Open
Abstract
The dentition is an extremely important organ in mammals with variation in timing and sequence of eruption, crown morphology, and tooth size enabling a range of behavioral, dietary, and functional adaptations across the class. Within this suite of variable mammalian dental phenotypes, relative sizes of teeth reflect variation in the underlying genetic and developmental mechanisms. Two ratios of postcanine tooth lengths capture the relative size of premolars to molars (premolar-molar module, PMM), and among the three molars (molar module component, MMC), and are known to be heritable, independent of body size, and to vary significantly across primates. Here, we explore how these dental traits vary across mammals more broadly, focusing on terrestrial taxa in the clade of Boreoeutheria (Euarchontoglires and Laurasiatheria). We measured the postcanine teeth of N = 1,523 boreoeutherian mammals spanning six orders, 14 families, 36 genera, and 49 species to test hypotheses about associations between dental proportions and phylogenetic relatedness, diet, and life history in mammals. Boreoeutherian postcanine dental proportions sampled in this study carry conserved phylogenetic signal and are not associated with variation in diet. The incorporation of paleontological data provides further evidence that dental proportions may be slower to change than is dietary specialization. These results have implications for our understanding of dental variation and dietary adaptation in mammals.
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Affiliation(s)
- Tesla A. Monson
- Department of Integrative BiologyUniversity of CaliforniaBerkeleyCalifornia
- Human Evolution Research CenterUniversity of CaliforniaBerkeleyCalifornia
- Museum of Vertebrate ZoologyUniversity of CaliforniaBerkeleyCalifornia
- Anthropologisches Institut und MuseumUniversität ZürichZürichSwitzerland
| | | | - Marianne F. Brasil
- Department of Integrative BiologyUniversity of CaliforniaBerkeleyCalifornia
- Human Evolution Research CenterUniversity of CaliforniaBerkeleyCalifornia
| | - Selene M. Clay
- Department of Integrative BiologyUniversity of CaliforniaBerkeleyCalifornia
- Department of Human GeneticsUniversity of ChicagoChicagoIllinois
| | - Rena Dvoretzky
- Department of Integrative BiologyUniversity of CaliforniaBerkeleyCalifornia
| | | | | | | | - Risa Takenaka
- Department of Integrative BiologyUniversity of CaliforniaBerkeleyCalifornia
- Museum of Vertebrate ZoologyUniversity of CaliforniaBerkeleyCalifornia
| | - Peter S. Ungar
- Department of AnthropologyUniversity of ArkansasFayettevilleArkansas
| | - Sunwoo Yoo
- Department of Integrative BiologyUniversity of CaliforniaBerkeleyCalifornia
| | - Michael Zhou
- Department of Integrative BiologyUniversity of CaliforniaBerkeleyCalifornia
| | | | - Leslea J. Hlusko
- Department of Integrative BiologyUniversity of CaliforniaBerkeleyCalifornia
- Human Evolution Research CenterUniversity of CaliforniaBerkeleyCalifornia
- Museum of Vertebrate ZoologyUniversity of CaliforniaBerkeleyCalifornia
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16
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Simpson SW, Levin NE, Quade J, Rogers MJ, Semaw S. Ardipithecus ramidus postcrania from the Gona Project area, Afar Regional State, Ethiopia. J Hum Evol 2019; 129:1-45. [DOI: 10.1016/j.jhevol.2018.12.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 11/26/2018] [Accepted: 12/05/2018] [Indexed: 11/30/2022]
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17
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Billet G, Bardin J. Serial Homology and Correlated Characters in Morphological Phylogenetics: Modeling the Evolution of Dental Crests in Placentals. Syst Biol 2018; 68:267-280. [DOI: 10.1093/sysbio/syy071] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 10/22/2018] [Indexed: 01/24/2023] Open
Affiliation(s)
- Guillaume Billet
- CR2P, UMR 7207, Muséum national d’Histoire naturelle, CNRS, Sorbonne Université, 8 rue Buffon 75005 Paris, France
| | - Jérémie Bardin
- CR2P, UMR 7207, Sorbonne Université, MNHN, CNRS, T.46-56, E.5, case 104, 4 place Jussieu, 75252 Paris cedex 05, France
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18
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Simpson SW, Latimer B, Lovejoy CO. Why Do Knuckle-Walking African Apes Knuckle-Walk? Anat Rec (Hoboken) 2018; 301:496-514. [DOI: 10.1002/ar.23743] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Revised: 10/18/2017] [Accepted: 10/30/2017] [Indexed: 12/19/2022]
Affiliation(s)
- Scott W. Simpson
- Department of Anatomy; Case Western Reserve University School of Medicine; Cleveland Ohio
- Laboratory of Physical Anthropology; Cleveland Museum of Natural History; Cleveland Ohio
| | - Bruce Latimer
- Department of Orthodontics; Case Western Reserve University School of Dental Medicine; Cleveland Ohio
- Laboratory of Physical Anthropology; Cleveland Museum of Natural History; Cleveland Ohio
| | - C. Owen Lovejoy
- Department of Anthropology; Kent State University; Kent Ohio
- Laboratory of Physical Anthropology; Cleveland Museum of Natural History; Cleveland Ohio
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19
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Morimoto N, Nakatsukasa M, Ponce de León MS, Zollikofer CPE. Femoral ontogeny in humans and great apes and its implications for their last common ancestor. Sci Rep 2018; 8:1930. [PMID: 29386644 PMCID: PMC5792642 DOI: 10.1038/s41598-018-20410-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Accepted: 01/18/2018] [Indexed: 11/09/2022] Open
Abstract
Inferring the morphology of the last common ancestor of humans, chimpanzees and gorillas is a matter of ongoing debate. Recent findings and reassessment of fossil hominins leads to the hypothesis that the last common ancestor was not extant African ape-like. However, an African great-ape-like ancestor with knuckle walking features still remains plausible and the most parsimonious scenario. Here we address this question via an evolutionary developmental approach, comparing taxon-specific patterns of shape change of the femoral diaphysis from birth to adulthood in great apes, humans, and macaques. While chimpanzees and gorillas exhibit similar locomotor behaviors, our data provide evidence for distinct ontogenetic trajectories, indicating independent evolutionary histories of femoral ontogeny. Our data further indicate that anthropoid primates share a basic pattern of femoral diaphyseal ontogeny that reflects shared developmental constraints. Humans escaped from these constraints via differential elongation of femur.
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Affiliation(s)
- Naoki Morimoto
- Laboratory of Physical Anthropology, Graduate School of Science, Kyoto University, Kyoto, Japan.
| | - Masato Nakatsukasa
- Laboratory of Physical Anthropology, Graduate School of Science, Kyoto University, Kyoto, Japan
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20
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Betti L. Human Variation in Pelvic Shape and the Effects of Climate and Past Population History. Anat Rec (Hoboken) 2017; 300:687-697. [PMID: 28297180 DOI: 10.1002/ar.23542] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 08/30/2016] [Accepted: 10/20/2016] [Indexed: 12/13/2022]
Abstract
The human pelvis is often described as an evolutionary compromise (obstetrical dilemma) between the requirements of efficient bipedal locomotion and safe parturition of a highly encephalized neonate, that has led to a tight fit between the birth canal and the head and body of the foetus. Strong evolutionary constraints on the shape of the pelvis can be expected under this scenario. On the other hand, several studies have found a significant level of pelvic variation within and between human populations, a fact that seems to contradict such expectations. The advantages of a narrow pelvis for locomotion have recently been challenged, suggesting that the tight cephalo-pelvic fit might not stem from the hypothesized obstetrical dilemma. Moreover, the human pelvis appears to be under lower constraints and to have relatively higher evolvability than other closely related primates. These recent findings substantially change the way in which we interpret variation in the human pelvis, and help make sense of the high diversity in pelvic shape observed within and among modern populations. A lower magnitude of covariance between functionally important regions ensured that a wide range of morphological variation was available within populations, enabling natural selection to generate pelvic variation between populations living in different environments. Neutral processes such as genetic drift and differential migration also contributed to shaping modern pelvic diversity during and after the expansion of humans into and across the various continents. Anat Rec, 300:687-697, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Lia Betti
- Centre for Research in Evolutionary, Social and Inter-Disciplinary Anthropology, Department of Life Sciences, University of Roehampton, London, SW15 4JD, UK
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21
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Churchill SE, Vansickle C. Pelvic Morphology in Homo erectus
and Early Homo. Anat Rec (Hoboken) 2017; 300:964-977. [DOI: 10.1002/ar.23576] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 01/20/2017] [Accepted: 02/03/2017] [Indexed: 01/06/2023]
Affiliation(s)
- Steven Emilio Churchill
- Department of Evolutionary Anthropology; Duke University; Durham North Carolina
- Evolutionary Studies Institute and Centre for Excellence in Palaeosciences, University of the Witwatersrand; Wits South Africa
| | - Caroline Vansickle
- Department of Anthropology; Bryn Mawr College; Bryn Mawr Pennsylvania
- Evolutionary Studies Institute and Centre for Excellence in Palaeosciences, University of the Witwatersrand; Wits South Africa
- Department of Anthropology; University of Wisconsin-Madison; Wisconsin
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22
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Lewton KL, Scott JE. Ischial Form as an Indicator of Bipedal Kinematics in Early Hominins: A Test Using Extant Anthropoids. Anat Rec (Hoboken) 2017; 300:845-858. [DOI: 10.1002/ar.23543] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Revised: 09/12/2016] [Accepted: 10/09/2016] [Indexed: 11/11/2022]
Affiliation(s)
- Kristi L. Lewton
- Department of Cell and Neurobiology, Keck School of Medicine; University of Southern California; Los Angeles California
- Department of Biological Sciences; University of Southern California; Los Angeles California
| | - Jeremiah E. Scott
- Department of Anthropology; Southern Illinois University; Carbondale Illinois
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23
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Rein TR, Harrison T, Carlson KJ, Harvati K. Adaptation to suspensory locomotion in Australopithecus sediba. J Hum Evol 2017; 104:1-12. [DOI: 10.1016/j.jhevol.2016.12.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Revised: 12/22/2016] [Accepted: 12/23/2016] [Indexed: 10/20/2022]
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24
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Selby MS, Lovejoy CO. Evolution of the hominoid scapula and its implications for earliest hominid locomotion. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2017; 162:682-700. [PMID: 28128440 DOI: 10.1002/ajpa.23158] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Revised: 11/06/2016] [Accepted: 12/08/2016] [Indexed: 11/06/2022]
Abstract
OBJECTIVES The higher primate scapula has been subject to many explanations of the putative "adaptive value" of its individual traits. However, the shift from the bone's position in above branch quadrupeds to its more posterolateral position in recent hominoids obviously required fundamental changes to its general form. We hypothesize that most features argued to be individually adaptive are more likely secondary consequences of changes in its fundamental bauplan, a view more consistent with modern developmental biology. MATERIALS AND METHODS We tested this hypothesis with scapular metrics and angles from a broad anthropoid sample. RESULTS Our results support our hypothesis. Contrary to earlier predictions, vertebral border length differs little relative to body size in anthropoids, inferior angle position primarily reflects mediolateral scapular breadth, and supraspinous and infraspinous fossa sizes largely reflect scapular spine orientation. Suspensory taxa have cranially oriented glenoids, whereas slow clamberers and humans do not. Australopithecus most closely resembles the latter. DISCUSSION Most scapular features can be explained by only two primary changes: (1) reduction in mediolateral breadth and (2) change in the glenoid position relative to the vertebral border with increased reliance on suspension, which led to a more cranially angled scapular spine. Virtually all other scapular traits appear to be byproducts of these two changes. Based on fossil morphology, hominids1 were derived from a last common ancestor primarily adapted for clambering and not for suspension. Scapular form in early hominids such as Australopithecus is therefore primitive and largely reflects the genus's general clambering heritage.
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Affiliation(s)
- Michael S Selby
- Department of Biomedical Sciences, Georgia Campus - Philadelphia College of Osteopathic Medicine, Suwanee, Georgia, 30024-2937
| | - C Owen Lovejoy
- Department of Anthropology, School of Biomedical Sciences, Kent State University, Kent, Ohio, 44242-0001
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25
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Abstract
The strikingly high incidence of obstructed labor due to the disproportion of fetal size and the mother's pelvic dimensions has puzzled evolutionary scientists for decades. Here we propose that these high rates are a direct consequence of the distinct characteristics of human obstetric selection. Neonatal size relative to the birth-relevant maternal dimensions is highly variable and positively associated with reproductive success until it reaches a critical value, beyond which natural delivery becomes impossible. As a consequence, the symmetric phenotype distribution cannot match the highly asymmetric, cliff-edged fitness distribution well: The optimal phenotype distribution that maximizes population mean fitness entails a fraction of individuals falling beyond the "fitness edge" (i.e., those with fetopelvic disproportion). Using a simple mathematical model, we show that weak directional selection for a large neonate, a narrow pelvic canal, or both is sufficient to account for the considerable incidence of fetopelvic disproportion. Based on this model, we predict that the regular use of Caesarean sections throughout the last decades has led to an evolutionary increase of fetopelvic disproportion rates by 10 to 20%.
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26
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Selby MS, Simpson SW, Lovejoy CO. The Functional Anatomy of the Carpometacarpal Complex in Anthropoids and Its Implications for the Evolution of the Hominoid Hand. Anat Rec (Hoboken) 2016; 299:583-600. [PMID: 26916787 DOI: 10.1002/ar.23333] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Revised: 11/01/2015] [Accepted: 01/12/2016] [Indexed: 11/09/2022]
Abstract
Previously, we described several features of the carpometacarpal joints in extant large-bodied apes that are likely adaptations to the functional demands of vertical climbing and suspension. We observed that all hominids, including modern humans and the 4.4-million-year-old hominid Ardipithecus ramidus, lacked these features. Here, we assess the uniqueness of these features in a large sample of monkey, ape, and human hands. These new data provide additional insights into the functional adaptations and evolution of the anthropoid hand. Our survey highlights a series of anatomical adaptations that restrict motion between the second and third metacarpals (MC2 and MC3) and their associated carpals in extant apes, achieved via joint reorganization and novel energy dissipation mechanisms. Their hamate-MC4 and -MC5 joint surface morphologies suggest limited mobility, at least in Pan. Gibbons and spider monkeys have several characters (angled MC3, complex capitate-MC3 joint topography, variably present capitate-MC3 ligaments) that suggest functional convergence in response to suspensory locomotion. Baboons have carpometacarpal morphology suggesting flexion/extension at these joints beyond that observed in most other Old World monkeys, probably as an energy dissipating mechanism minimizing collision forces during terrestrial locomotion. All hominids lack these specializations of the extant great apes, suggesting that vertical climbing was never a central feature of our ancestral locomotor repertoire. Furthermore, the reinforced carpometacarpus of vertically climbing African apes was likely appropriated for knuckle-walking in concert with other novel potential energy dissipating mechanisms. The most parsimonious explanation of the structural similarity of these carpometacarpal specializations in great apes is that they evolved independently.
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Affiliation(s)
- Michael S Selby
- Department of Biomedical Sciences, Georgia Campus-Philadelphia College of Osteopathic Medicine, Suwanee, Georgia
| | - Scott W Simpson
- Department of Anatomy, Case Western Reserve University School of Medicine, Cleveland, Ohio
- Laboratory of Physical Anthropology, Cleveland Museum of Natural History, 1 Wade Oval Drive, Cleveland, Ohio
| | - C Owen Lovejoy
- Laboratory of Physical Anthropology, Cleveland Museum of Natural History, 1 Wade Oval Drive, Cleveland, Ohio
- Department of Anthropology, School of Biomedical Sciences, Kent State University, Kent, Ohio
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27
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Waxenbaum EB, Stock MK. Variation in the human bicondylar angle. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2016; 160:334-40. [DOI: 10.1002/ajpa.22972] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2015] [Revised: 01/11/2016] [Accepted: 02/12/2016] [Indexed: 11/08/2022]
Affiliation(s)
- Erin B. Waxenbaum
- Department of Anthropology; Northwestern University; Evanston IL 60208
| | - Michala K. Stock
- Department of Anthropology; University of Florida; Gainesville FL 32610
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28
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Tallman M. Shape Ontogeny of the Distal Femur in the Hominidae with Implications for the Evolution of Bipedality. PLoS One 2016; 11:e0148371. [PMID: 26886416 PMCID: PMC4757424 DOI: 10.1371/journal.pone.0148371] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Accepted: 01/18/2016] [Indexed: 01/31/2023] Open
Abstract
Heterochrony has been invoked to explain differences in the morphology of modern humans as compared to other great apes. The distal femur is one area where heterochrony has been hypothesized to explain morphological differentiation among Plio-Pleistocene hominins. This hypothesis is evaluated here using geometric morphometric data to describe the ontogenetic shape trajectories of extant hominine distal femora and place Plio-Pleistocene hominins within that context. Results of multivariate statistical analyses showed that in both Homo and Gorilla, the shape of the distal femur changes significantly over the course of development, whereas that of Pan changes very little. Development of the distal femur of Homo is characterized by an elongation of the condyles, and a greater degree of enlargement of the medial condyle relative to the lateral condyle, whereas Gorilla are characterized by a greater degree of enlargement of the lateral condyle, relative to the medial. Early Homo and Australopithecus africanus fossils fell on the modern human ontogenetic shape trajectory and were most similar to either adult or adolescent modern humans while specimens of Australopithecus afarensis were more similar to Gorilla/Pan. These results indicate that shape differences among the distal femora of Plio-Pleistocene hominins and humans cannot be accounted for by heterochrony alone; heterochrony could explain a transition from the distal femoral shape of early Homo/A. africanus to modern Homo, but not a transition from A. afarensis to Homo. That change could be the result of genetic or epigenetic factors.
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Affiliation(s)
- Melissa Tallman
- Department of Biomedical Sciences, Grand Valley State University, Allendale, MI, United States of America
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29
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Nadell JA, Shaw CN. Phenotypic plasticity and constraint along the upper and lower limb diaphyses ofHomo sapiens. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2015; 159:410-22. [DOI: 10.1002/ajpa.22889] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Revised: 10/16/2015] [Accepted: 10/18/2015] [Indexed: 11/10/2022]
Affiliation(s)
| | - Colin N. Shaw
- Department of Archaeology and Anthropology; University of Cambridge; Cambridge UK
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30
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Drapeau MSM. Metacarpal torsion in apes, humans, and early Australopithecus: implications for manipulatory abilities. PeerJ 2015; 3:e1311. [PMID: 26500820 PMCID: PMC4614803 DOI: 10.7717/peerj.1311] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 09/19/2015] [Indexed: 12/03/2022] Open
Abstract
Human hands, when compared to that of apes, have a series of adaptations to facilitate manipulation. Numerous studies have shown that Australopithecus afarensis and Au. africanus display some of these adaptations, such as a longer thumb relative to the other fingers, asymmetric heads on the second and fifth metacarpals, and orientation of the second metacarpal joints with the trapezium and capitate away from the sagittal plane, while lacking others such as a very mobile fifth metacarpal, a styloid process on the third, and a flatter metacarpo-trapezium articulation, suggesting some adaptation to manipulation but more limited than in humans. This paper explores variation in metacarpal torsion, a trait said to enhance manipulation, in humans, apes, early australopithecines and specimens from Swartkrans. This study shows that humans are different from large apes in torsion of the third and fourth metacarpals. Humans are also characterized by wedge-shaped bases of the third and fourth metacarpals, making the metacarpal-base row very arched mediolaterally and placing the ulnar-most metacarpals in a position that facilitate opposition to the thumb in power or cradle grips. The third and fourth metacarpals of Au. afarensis are very human-like, suggesting that the medial palm was already well adapted for these kinds of grips in that taxon. Au. africanus present a less clear human-like morphology, suggesting, perhaps, that the medial palm was less suited to human-like manipulation in that taxa than in Au. afarensis. Overall, this study supports previous studies on Au. afarensis and Au. africanus that these taxa had derived hand morphology with some adaptation to human-like power and precision grips and support the hypothesis that dexterous hands largely predated Homo.
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31
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Sylvester AD. Femoral condyle curvature is correlated with knee walking kinematics in ungulates. Anat Rec (Hoboken) 2015; 298:2039-50. [PMID: 26414648 DOI: 10.1002/ar.23274] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Revised: 07/09/2015] [Accepted: 08/04/2015] [Indexed: 11/10/2022]
Abstract
The knee has been the focus of many studies linking mammalian postcranial form with locomotor behaviors and animal ecology. A more difficult task has been linking joint morphology with joint kinematics during locomotor tasks. Joint curvature represents one opportunity to link postcranial morphology with walking kinematics because joint curvature develops in response to mechanical loading. As an initial examination of mammalian knee joint curvature, the curvature of the medial femoral condyle was measured on femora representing 11 ungulate species. The position of a region of low curvature was measured using a metric termed the "angle to low curvature". This low-curvature region is important because it provides the greatest contact area between femoral and tibial condyles. Kinematic knee angles during walking were derived from the literature and kinematic knee angles across the gait cycle were correlated with angle to low curvature values. The highest correlation between kinematic knee angle and the angle to low curvature metric occurred at 20% of the walking gait cycle. This early portion of the walking gait cycle is associated with a peak in the vertical ground reaction force for some mammals. The chondral modeling theory predicts that frequent and heavy loading of particular regions of a joint surface during ontogeny will result in these regions being flatter than the surrounding joint surface. The locations of flatter regions of the femoral condyles of ungulates, and their association with knee angles used during the early stance phase of walking provides support for the chondral modeling theory.
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Affiliation(s)
- Adam D Sylvester
- Center for Functional Anatomy and Evolution, Johns Hopkins University School of Medicine, 1830 E. Monument Street, Baltimore, Maryland
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32
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Grabowski M, Roseman CC. Complex and changing patterns of natural selection explain the evolution of the human hip. J Hum Evol 2015; 85:94-110. [DOI: 10.1016/j.jhevol.2015.05.008] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2013] [Revised: 05/12/2015] [Accepted: 05/13/2015] [Indexed: 12/22/2022]
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33
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Tulli MJ, Carrizo LV, Samuels JX. Morphological Variation of the Forelimb and Claw in Neotropical Sigmodontine Rodents (Rodentia: Cricetidae). J MAMM EVOL 2015. [DOI: 10.1007/s10914-015-9300-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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34
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von Cramon-Taubadel N, Lycett SJ. A comparison of catarrhine genetic distances with pelvic and cranial morphology: implications for determining hominin phylogeny. J Hum Evol 2014; 77:179-86. [PMID: 25439629 DOI: 10.1016/j.jhevol.2014.06.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Revised: 02/28/2014] [Accepted: 06/12/2014] [Indexed: 11/15/2022]
Abstract
Inferring the evolutionary history of the hominins is necessarily reliant on comparative analyses of fossilized skeletal anatomy. However, the reliability of different primate skeletal regions for recovering phylogenetic relationships is currently poorly understood. Historically, postcranial variation has largely been conceived of as reflecting locomotory and postural adaptation. The shape of the os coxae is central to such discussions given the divergent morphology displayed by the bipedal hominin pelvis relative to other primate taxa. While previous cladistic studies have suggested that postcranial and cranial datasets do not differ in terms of their propensity for homoplasy, methodological issues such as the numbers of characters and their quantification make it difficult to evaluate these findings. Here, we circumvent these problems by constructing morphological distance matrices based on cranial, mandibular and os coxae three-dimensional shape. Statistical comparisons of these morphological distance matrices against a single genetic distance matrix for 11 catarrhine taxa show that cranial and os coxae shape reflect genetic relationships better than the mandible when humans are included, and that the cranium and os coxae do not differ statistically in terms of their genetic correlations. When humans were excluded from the analyses, all three anatomical regions were equally strongly correlated with genetic distance. Moreover, a second analysis focusing solely on os coxae variation of 16 taxa demonstrated that os coxae shape correctly recovers catarrhine taxonomic relationships at the sub-family level, even when humans are included. Taken together, our results suggest that there is no a priori reason to favor cranial shape data over os coxae morphology when inferring the genetic relationships of extant or extinct primate taxa. Morphological similarities between humans and other primates differ depending on the skeletal element, suggesting that combining skeletal elements into a single analysis may provide more accurate reconstructions of genetic relationships.
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Affiliation(s)
| | - Stephen J Lycett
- Department of Anthropology, University at Buffalo, SUNY, New York 14261-0005, USA
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35
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Abstract
Environmental temperature can have a surprising impact on extremity growth in homeotherms, but the underlying mechanisms have remained elusive for over a century. Limbs of animals raised at warm ambient temperature are significantly and permanently longer than those of littermates housed at cooler temperature. These remarkably consistent lab results closely resemble the ecogeographical tenet described by Allen's "extremity size rule," that appendage length correlates with temperature and latitude. This phenotypic growth plasticity could have adaptive significance for thermal physiology. Shortened extremities help retain body heat in cold environments by decreasing surface area for potential heat loss. Homeotherms have evolved complex mechanisms to maintain tightly regulated internal temperatures in challenging environments, including "facultative extremity heterothermy" in which limb temperatures can parallel ambient. Environmental modulation of tissue temperature can have direct and immediate consequences on cell proliferation, metabolism, matrix production, and mineralization in cartilage. Temperature can also indirectly influence cartilage growth by modulating circulating levels and delivery routes of essential hormones and paracrine regulators. Using an integrated approach, this article synthesizes classic studies with new data that shed light on the basis and significance of this enigmatic growth phenomenon and its relevance for treating human bone elongation disorders. Discussion centers on the vasculature as a gateway to understanding the complex interconnection between direct (local) and indirect (systemic) mechanisms of temperature-enhanced bone lengthening. Recent advances in imaging modalities that enable the dynamic study of cartilage growth plates in vivo will be key to elucidating fundamental physiological mechanisms of long bone growth regulation.
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Affiliation(s)
- Maria A Serrat
- Department of Anatomy and Pathology, Joan C. Edwards School of Medicine, Marshall University, Huntington, West Virginia
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Lovejoy CO. Ardipithecusand Early Human Evolution in Light of Twenty-First-Century Developmental Biology. JOURNAL OF ANTHROPOLOGICAL RESEARCH 2014. [DOI: 10.3998/jar.0521004.0070.301] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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37
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Kraft TS, Venkataraman VV, Dominy NJ. A natural history of human tree climbing. J Hum Evol 2014; 71:105-18. [DOI: 10.1016/j.jhevol.2014.02.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Revised: 07/22/2013] [Accepted: 02/03/2014] [Indexed: 12/18/2022]
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Foster AD, Raichlen DA, Pontzer H. Muscle force production during bent-knee, bent-hip walking in humans. J Hum Evol 2013; 65:294-302. [DOI: 10.1016/j.jhevol.2013.06.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2012] [Revised: 06/24/2013] [Accepted: 06/26/2013] [Indexed: 11/16/2022]
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Daegling DJ, Judex S, Ozcivici E, Ravosa MJ, Taylor AB, Grine FE, Teaford MF, Ungar PS. Viewpoints: Feeding mechanics, diet, and dietary adaptations in early hominins. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2013; 151:356-71. [DOI: 10.1002/ajpa.22281] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Accepted: 03/24/2013] [Indexed: 11/09/2022]
Affiliation(s)
- David J. Daegling
- Department of Anthropology; University of Florida; Gainesville; FL; 32605
| | - Stefan Judex
- Department of Biomedical Engineering; Stony Brook University; Stony Brook; NY; 11794-5281
| | - Engin Ozcivici
- Department of Mechanical Engineering; Izmir Institute of Technology; Urla; Izmir; 35430; Turkey
| | | | | | | | - Mark F. Teaford
- Department of Physical Therapy; High Point University; High Point; NC; 27262-3598
| | - Peter S. Ungar
- Department of Anthropology; University of Arkansas; Fayetteville; AR; 72701
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Venkataraman VV, Kraft TS, Desilva JM, Dominy NJ. Phenotypic Plasticity of Climbing-Related Traits in the Ankle Joint of Great Apes and Rainforest Hunter-Gatherers. Hum Biol 2013; 85:309-28. [DOI: 10.3378/027.085.0315] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/02/2013] [Indexed: 11/05/2022]
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Reno PL, Horton WE, Lovejoy CO. Metapodial or phalanx? An evolutionary and developmental perspective on the homology of the first ray's proximal segment. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2013; 320:276-85. [PMID: 23640850 DOI: 10.1002/jez.b.22506] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Revised: 03/29/2013] [Accepted: 04/01/2013] [Indexed: 12/30/2022]
Abstract
The first mammalian metapodial (MP1) has periodically been argued to actually be a phalanx, because the first ray has one less element than the four posterior rays, and because the MP1 growth plate is proximal like those of all phalanges, rather than distal as in metapodials 2-5. However, growth plates are formed at both ends in non-therian tetrapod metapodials, and phylogenetic analysis demonstrates that growth plate loss is a therian synapomorphy that postdates the establishment of the mammalian phalangeal formula. These data, along with results of developmental and morphological studies, suggest that the MP1 is not a phalanx. The singular, proximal growth plates in MPs 2-5 are likely to be an adaptation to dynamic erect quadrupedal gait which was characterized by conversion of the posterior metapodials into rigid struts with the carpus/tarsus. While the adaptive significance of the reversed ossification of MP1 is less clear, we present three functional/developmental hypotheses.
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Affiliation(s)
- Philip L Reno
- Department of Anthropology, The Pennsylvania State University, University Park, Pennsylvania, USA.
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43
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Sayers K, Raghanti MA, Lovejoy CO. Human Evolution and the Chimpanzee Referential Doctrine. ANNUAL REVIEW OF ANTHROPOLOGY 2012. [DOI: 10.1146/annurev-anthro-092611-145815] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Chimpanzees are our closest living genomic relatives, but they lack the bipedal locomotion, markedly enlarged brains, and advanced communication skills of humans. This has led many to view them as “primitive” and to presume that their behavior and anatomy are also primitive. If true, they could serve as models of our last common ancestor (LCA), i.e., a territorially aggressive knuckle walker, reliant on vertical climbing and below-branch suspension to access the high canopy as a ripe-fruit frugivore. Ardipithecus now provides abundant information that the LCA differed substantially from chimpanzees (as well as bonobos and gorillas), both anatomically and behaviorally, and exhibited many characters that are more similar to those of modern humans than to any living ape. This major extension of the hominoid fossil record contravenes strict referential modeling based on the extant chimpanzee and greatly improves our ability to reconstruct the LCA more accurately, but only when viewed within the broader context of evolutionary ecology.
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Affiliation(s)
- Ken Sayers
- Language Research Center, Georgia State University, Decatur, Georgia 30034
| | - Mary Ann Raghanti
- Department of Anthropology and Division of Biomedical Sciences, Kent State University, Kent, Ohio 44242;,
| | - C. Owen Lovejoy
- Department of Anthropology and Division of Biomedical Sciences, Kent State University, Kent, Ohio 44242;,
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Sylvester AD, Pfisterer T. Quantifying lateral femoral condyle ellipticalness in chimpanzees, gorillas, and humans. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2012; 149:458-67. [DOI: 10.1002/ajpa.22144] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2011] [Accepted: 08/20/2012] [Indexed: 11/09/2022]
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More than just a bump: cam-type femoroacetabular impingement and the evolution of the femoral neck. Hip Int 2011; 21:1-8. [PMID: 21279972 DOI: 10.5301/hip.2011.6288] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/27/2010] [Indexed: 02/04/2023]
Abstract
Recent orthopaedic literature has implicated femoroacetabular impingement, the pathologic abutment of structural aberrancies in the proximal femur and acetabular rim, as an important cause of groin pain in young individuals and a potential factor in early idiopathic osteoarthritis. The etiology and risk factors for developing cam-type morphology are still unknown. The osseous anatomy of the proximal femur in humans is the culmination of nearly 400 million years of evolution. Coxa recta and coxa rotunda are the two predominant morphologies in modern animals. While the former, characterized by a straight head-neck junction, is often present in cursorial creatures, the latter, [corrected] distinguished by high offset at this junction, is exemplified in most humans. Based on the ontology and phylogeny of the proximal femur, coxa rotunda probably developed from a more primitive coxa recta. We believe that cam-type morphology is neither a redevelopment of coxa recta nor a malformation such as slipped capital epiphysis. The aspherical osteocartilaginous bump is associated with an extended physis and has been noted to appear during mid-adolescence. While this protuberance may contribute to future pathology, the authors feel that increased loading of the hip, not impingement activities, during late childhood and early adolescence predispose patients to develop this morphology.
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46
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Roseman CC, Weaver TD, Stringer CB. Do modern humans and Neandertals have different patterns of cranial integration? J Hum Evol 2011; 60:684-93. [DOI: 10.1016/j.jhevol.2010.04.010] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2009] [Revised: 03/01/2010] [Accepted: 08/09/2010] [Indexed: 11/29/2022]
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47
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Bonneau N, Simonis C, Seringe R, Tardieu C. Study of femoral torsion during prenatal growth: interpretations associated with the effects of intrauterine pressure. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2011; 145:438-45. [PMID: 21541926 DOI: 10.1002/ajpa.21521] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2010] [Accepted: 01/31/2011] [Indexed: 01/25/2023]
Abstract
The developing fetus is protected from external environmental influences by maternal tissues. However, these structures have a limited elasticity, such that the fetus must grow in a confined space, constraining its size at the end of pregnancy. Can these constraints modify the morphology of the fetal skeleton? The intensity of these constraints increases between 5 months and birth, making it the most appropriate period to address this question. A sample of 89 fetal femora was analyzed, and results provide evidence that during this period, the torsion of the femoral shaft (quantified by means of a new three-dimensional method) increases gradually. Two explanations were considered: this increase could signal effects of constraints induced by the intrauterine cavity, developmental patterning, or some combination of these two. Different arguments tend to support the biomechanical explanation, rather than a programming pattern formation. Indeed, the identification of the femur as a first degree lever, created by the hyperflexion of the fetal lower limbs on the pelvis, could explain the increase in femoral shaft torsion during prenatal life. A comparison with femora of infants is in accordance with this mechanical interpretation, which is possible through bone modeling/remodeling. Although genetic and epigenetic mechanisms may regulate timing of fetal development, our data suggest that at birth, the fetal skeleton also has an intrauterine mechanical history through adaptive bone plasticity.
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Affiliation(s)
- Noémie Bonneau
- UMR CNRS-Muséum National d'Histoire Naturelle, Paris, France.
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48
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Abel R, Macho GA. Ontogenetic changes in the internal and external morphology of the ilium in modern humans. J Anat 2011; 218:324-35. [PMID: 21323915 PMCID: PMC3058218 DOI: 10.1111/j.1469-7580.2011.01342.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/07/2011] [Indexed: 11/29/2022] Open
Abstract
Trabecular architecture forms an important structural component of bone and, depending on the loading conditions encountered during life, is organised in a systematic, bone- and species-specific manner. However, recent studies suggested that gross trabecular arrangement (e.g. density distribution), like overall bone shape, is predetermined and/or affected by factors other than loading and perhaps less plastic than commonly assumed. To explore this issue further, the present cross-sectional ontogenetic study investigated morphological changes in external bone shape in relation to changes in trabecular bundle orientation and anisotropy. Radiographs of 73 modern human ilia were assessed using radiographic and Geometric Morphometric techniques. The study confirmed the apparently strong predetermination of trabecular bundle development, i.e. prior to external loading, although loading clearly also had an effect on overall morphology. For example, the sacro-pubic bundle, which follows the path of load transmission from the auricular surface to the acetabulum, is well defined and shows relatively high levels of anisotropy from early stages of development; the situation for the ischio-iliac strut is similar. However, while the sacro-pubic strut retains a constant relationship with the external landmarks defining the joint surfaces, the ischio-iliac bundle changes its relationship with the external landmarks and becomes aligned with the iliac tubercle only during late adolescence/early adulthood. It is tentatively proposed that the rearrangement of the ischio-iliac strut may reflect a change in locomotor pattern and/or a shift in positional behavior with increasing mass after growth of external bone dimensions has slowed/ceased.
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Affiliation(s)
- Richard Abel
- Imperial College London, Charing Cross Campus, London, UK
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49
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Grabowski MW, Polk JD, Roseman CC. DIVERGENT PATTERNS OF INTEGRATION AND REDUCED CONSTRAINT IN THE HUMAN HIP AND THE ORIGINS OF BIPEDALISM. Evolution 2011; 65:1336-56. [DOI: 10.1111/j.1558-5646.2011.01226.x] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Mark W. Grabowski
- Department of Anthropology, University of Illinois at Urbana‐Champaign, Urbana, Illinois 61801
- E‐mail:
| | - John D. Polk
- Department of Anthropology, University of Illinois at Urbana‐Champaign, Urbana, Illinois 61801
| | - Charles C. Roseman
- Department of Anthropology, University of Illinois at Urbana‐Champaign, Urbana, Illinois 61801
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50
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Wallace IJ. Evolution in real time. Evol Anthropol 2010. [DOI: 10.1002/evan.20271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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