1
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Miller CK, DeSilva JM. A review of the distal femur in Australopithecus. Evol Anthropol 2024; 33:e22012. [PMID: 38009942 DOI: 10.1002/evan.22012] [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: 07/22/2023] [Revised: 11/08/2023] [Accepted: 11/09/2023] [Indexed: 11/29/2023]
Abstract
In 1938, the first distal femur of a fossil Australopithecus was discovered at Sterkfontein, South Africa. A decade later, another distal femur was discovered at the same locality. These two fossil femora were the subject of a foundational paper authored by Kingsbury Heiple and Owen Lovejoy in 1971. In this paper, the authors discussed functionally relevant anatomies of these two fossil femora and noted their strong affinity to the modern human condition. Here, we update this work by including eight more fossil Australopithecus distal femora, an expanded comparative dataset, as well as additional linear measurements. Just as Heiple and Lovejoy reported a half-century ago, we find strong overlap between modern humans and cercopithecoids, except for inferiorly flattened condyles and a high bicondylar angle, both of which characterize modern humans and Australopithecus and are directly related to striding bipedalism. All other measured aspects of the femora are by-products of these key morphological traits. Additional fossil material from the early Pliocene will help to inform the evolution of the hominin distal femur and its condition in the Pan-Homo common ancestor that preceded bipedal locomotion.
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Affiliation(s)
- Catherine K Miller
- Department of Anthropology, Dartmouth College, Hanover, New Hampshire, USA
- Ecology, Evolution, Ecosystems, and Society Graduate Program, Dartmouth College, Hanover, New Hampshire, USA
| | - Jeremy M DeSilva
- Department of Anthropology, Dartmouth College, Hanover, New Hampshire, USA
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa
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2
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Fannin LD, Joy MS, Dominy NJ, McGraw WS, DeSilva JM. Downclimbing and the evolution of ape forelimb morphologies. R Soc Open Sci 2023; 10:230145. [PMID: 37680499 PMCID: PMC10480693 DOI: 10.1098/rsos.230145] [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] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 08/15/2023] [Indexed: 09/09/2023]
Abstract
The forelimbs of hominoid primates (apes) are decidedly more flexible than those of monkeys, especially at the shoulder, elbow and wrist joints. It is tempting to link the greater mobility of these joints to the functional demands of vertical climbing and below-branch suspension, but field-based kinematic studies have found few differences between chimpanzees and monkeys when comparing forelimb excursion angles during vertical ascent (upclimbing). There is, however, a strong theoretical argument for focusing instead on vertical descent (downclimbing), which motivated us to quantify the effects of climbing directionality on the forelimb kinematics of wild chimpanzees (Pan troglodytes) and sooty mangabeys (Cercocebus atys). We found that the shoulders and elbows of chimpanzees and sooty mangabeys subtended larger joint angles during bouts of downclimbing, and that the magnitude of this difference was greatest among chimpanzees. Our results cast new light on the functional importance of downclimbing, while also burnishing functional hypotheses that emphasize the role of vertical climbing during the evolution of apes, including the human lineage.
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Affiliation(s)
- Luke D. Fannin
- Department of Anthropology, Dartmouth College, Hanover, NH 03755, USA
- Ecology, Evolution, Environment and Society, Dartmouth College, Hanover, NH 03755, USA
| | - Mary S. Joy
- Department of Anthropology, Dartmouth College, Hanover, NH 03755, USA
| | - Nathaniel J. Dominy
- Department of Anthropology, Dartmouth College, Hanover, NH 03755, USA
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755, USA
| | - W. Scott McGraw
- Department of Anthropology, The Ohio State University, Columbus, OH 43210, USA
| | - Jeremy M. DeSilva
- Department of Anthropology, Dartmouth College, Hanover, NH 03755, USA
- Ecology, Evolution, Environment and Society, Dartmouth College, Hanover, NH 03755, USA
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3
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Harper CM, Zipfel B, DeSilva JM, McNutt EJ, Thackeray F, Braga J. A new early hominin calcaneus from Kromdraai (South Africa). J Anat 2022; 241:500-517. [DOI: 10.1111/joa.13660] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 03/16/2022] [Accepted: 03/17/2022] [Indexed: 12/22/2022] Open
Affiliation(s)
- Christine M. Harper
- Department of Biomedical Sciences Cooper Medical School of Rowan University Camden New Jersey USA
| | - Bernhard Zipfel
- Evolutionary Studies Institute University of the Witwatersrand Johannesburg South Africa
| | - Jeremy M. DeSilva
- Department of Anthropology Dartmouth College Hanover New Hampshire USA
| | - Ellison J. McNutt
- Department of Biomedical Sciences Ohio University Heritage College of Osteopathic Medicine Athens Ohio USA
| | - Francis Thackeray
- Evolutionary Studies Institute University of the Witwatersrand Johannesburg South Africa
| | - José Braga
- Evolutionary Studies Institute University of the Witwatersrand Johannesburg South Africa
- Centre d'Anthropobiologie et de Génomique de Toulouse Université Paul Sabatier Toulouse III Toulouse France
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4
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Abstract
Bipedal locomotion is a hallmark of being human. Yet the body form from which bipedalism evolved remains unclear. Specifically, the positional behaviour (i.e. orthograde vs. pronograde) and the length of the lumbar spine (i.e. long and mobile vs. short and stiff) of the last common ancestor (LCA) of the African great apes and humans require further investigation. While fossil evidence would be the most conclusive, the paucity of hominid fossils from 5-10 million years ago makes this field of research challenging. In their absence, extant primate anatomy and behaviour may offer some insight into the ancestral body form from which bipedalism could most easily evolve. Here, we quantify the frequency of bipedalism in a large sample (N = 496) of zoo-housed hominoids and cercopithecines. Our results show that while each studied species of ape and monkey can move bipedally, hylobatids are significantly more bipedal and engage in bipedal locomotion more frequently and for greater distances than any other primate sampled. These data support hypotheses of an orthograde, long-backed and arboreal LCA, which is consistent with hominoid fossils from the middle-to-late Miocene. If true, knuckle-walking evolved in parallel in Pan and Gorilla, and the human body form, particularly the long lower back and orthograde posture, is conserved.
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Affiliation(s)
- Kyle H. Rosen
- Department of Anthropology, Dartmouth College, 6047 Silsby Hall, Hanover, NH, USA
| | - Caroline E. Jones
- Department of Psychology, University of Georgia, 125 Baldwin Street, Athens, GA, USA
| | - Jeremy M. DeSilva
- Department of Anthropology, Dartmouth College, 6047 Silsby Hall, Hanover, NH, USA
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5
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Everett MC, Elliott MC, Gaynor D, Hill AC, Syeda SM, Casana J, Zipfel B, DeSilva JM, Dominy NJ. Mechanical loading of primate fingers on vertical rock surfaces. S AFR J SCI 2021. [DOI: 10.17159/sajs.2021/10409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Mechanical loading of finger bones (phalanges) can induce angular curvature, which benefits arboreal primates by dissipating forces and economising the recruitment of muscles during climbing. The recent discovery of extremely curved phalanges in a hominin, Homo naledi, is puzzling, for it suggests life in an arboreal milieu, or, alternatively, habitual climbing on vertical rock surfaces. The importance of climbing rock walls is attested by several populations of baboons, one of which uses a 7-m vertical surface to enter and exit Dronkvlei Cave, De Hoop Nature Reserve, South Africa. This rock surface is an attractive model for estimating the probability of extreme mechanical loading on the phalanges of rock-climbing primates. Here we use three-dimensional photogrammetry to show that 82–91% of the climbable surface would generate high forces on the flexor tendon pulley system and severely load the phalanges of baboons and H. naledi. If such proportions are representative of vertical rock surfaces elsewhere, it may be sufficient to induce stress-mitigating curvature in the phalanges of primates.
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Affiliation(s)
- Michael C. Everett
- Department of Anthropology, Dartmouth College, Hanover, New Hampshire, USA
| | - Marina C. Elliott
- Department of Archaeology, Simon Fraser University, Burnaby, British Columbia, Canada
- Centre for the Exploration of the Deep Human Journey, University of the Witwatersrand, Johannesburg, South Africa
| | - David Gaynor
- Mammal Research Institute, University of Pretoria, Pretoria, South Africa
| | - Austin C. Hill
- Department of Anthropology, Dartmouth College, Hanover, New Hampshire, USA
- Department of Anthropology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Samar M. Syeda
- Department of Anthropology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Jesse Casana
- Department of Anthropology, Dartmouth College, Hanover, New Hampshire, USA
| | - Bernhard Zipfel
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa
| | - Jeremy M. DeSilva
- Department of Anthropology, Dartmouth College, Hanover, New Hampshire, USA
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa
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6
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DeSilva JM, Traniello JFA, Claxton AG, Fannin LD. When and Why Did Human Brains Decrease in Size? A New Change-Point Analysis and Insights From Brain Evolution in Ants. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.742639] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Human brain size nearly quadrupled in the six million years since Homo last shared a common ancestor with chimpanzees, but human brains are thought to have decreased in volume since the end of the last Ice Age. The timing and reason for this decrease is enigmatic. Here we use change-point analysis to estimate the timing of changes in the rate of hominin brain evolution. We find that hominin brains experienced positive rate changes at 2.1 and 1.5 million years ago, coincident with the early evolution of Homo and technological innovations evident in the archeological record. But we also find that human brain size reduction was surprisingly recent, occurring in the last 3,000 years. Our dating does not support hypotheses concerning brain size reduction as a by-product of body size reduction, a result of a shift to an agricultural diet, or a consequence of self-domestication. We suggest our analysis supports the hypothesis that the recent decrease in brain size may instead result from the externalization of knowledge and advantages of group-level decision-making due in part to the advent of social systems of distributed cognition and the storage and sharing of information. Humans live in social groups in which multiple brains contribute to the emergence of collective intelligence. Although difficult to study in the deep history of Homo, the impacts of group size, social organization, collective intelligence and other potential selective forces on brain evolution can be elucidated using ants as models. The remarkable ecological diversity of ants and their species richness encompasses forms convergent in aspects of human sociality, including large group size, agrarian life histories, division of labor, and collective cognition. Ants provide a wide range of social systems to generate and test hypotheses concerning brain size enlargement or reduction and aid in interpreting patterns of brain evolution identified in humans. Although humans and ants represent very different routes in social and cognitive evolution, the insights ants offer can broadly inform us of the selective forces that influence brain size.
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7
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Prabhat AM, Miller CK, Prang TC, Spear J, Williams SA, DeSilva JM. Homoplasy in the evolution of modern human-like joint proportions in Australopithecus afarensis. eLife 2021; 10:65897. [PMID: 33978569 PMCID: PMC8116054 DOI: 10.7554/elife.65897] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [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: 12/18/2020] [Accepted: 04/19/2021] [Indexed: 11/22/2022] Open
Abstract
The evolution of bipedalism and reduced reliance on arboreality in hominins resulted in larger lower limb joints relative to the joints of the upper limb. The pattern and timing of this transition, however, remains unresolved. Here, we find the limb joint proportions of Australopithecus afarensis, Homo erectus, and Homo naledi to resemble those of modern humans, whereas those of A. africanus, Australopithecus sediba, Paranthropus robustus, Paranthropus boisei, Homo habilis, and Homo floresiensis are more ape-like. The homology of limb joint proportions in A. afarensis and modern humans can only be explained by a series of evolutionary reversals irrespective of differing phylogenetic hypotheses. Thus, the independent evolution of modern human-like limb joint proportions in A. afarensis is a more parsimonious explanation. Overall, these results support an emerging perspective in hominin paleobiology that A. afarensis was the most terrestrially adapted australopith despite the importance of arboreality throughout much of early hominin evolution.
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Affiliation(s)
| | - Catherine K Miller
- Anthropology, Dartmouth College, Hanover, United States.,Ecology, Evolution, Ecosystems, and Society, Dartmouth College, Hanover, United States
| | - Thomas Cody Prang
- Department of Anthropology, Texas A&M University, College Station, United States
| | - Jeffrey Spear
- Center for the Study of Human Origins, Department of Anthropology, New York University, New York, United States.,New York Consortium in Evolutionary Primatology, New York, United States
| | - Scott A Williams
- Center for the Study of Human Origins, Department of Anthropology, New York University, New York, United States.,New York Consortium in Evolutionary Primatology, New York, United States
| | - Jeremy M DeSilva
- Anthropology, Dartmouth College, Hanover, United States.,Ecology, Evolution, Ecosystems, and Society, Dartmouth College, Hanover, United States
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8
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DeSilva JM, McNutt E, Zipfel B, Ward CV, Kimbel WH. Associated Australopithecusafarensis second and third metatarsals (A.L. 333-133) from Hadar, Ethiopia. J Hum Evol 2020; 146:102848. [PMID: 32717476 DOI: 10.1016/j.jhevol.2020.102848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 06/05/2020] [Accepted: 06/05/2020] [Indexed: 10/23/2022]
Affiliation(s)
- Jeremy M DeSilva
- Department of Anthropology, Dartmouth College, Hanover, NH, 03755, USA.
| | - Ellison McNutt
- Keck School of Medicine, University of Southern California, Los Angeles, CA, 90033, USA
| | - Bernhard Zipfel
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa
| | - Carol V Ward
- Integrative Anatomy Program, Department of Pathology and Anatomical Sciences, School of Medicine, University of Missouri, Columbia, MO, 65212, USA
| | - William H Kimbel
- Institute of Human Origins and School of Human Evolution and Social Change, Arizona State University, Tempe, AZ, 85287, USA
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9
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McNutt EJ, DeSilva JM. Evidence for an elongated Achilles tendon in Australopithecus. Anat Rec (Hoboken) 2020; 303:2382-2391. [PMID: 32134211 DOI: 10.1002/ar.24387] [Citation(s) in RCA: 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] [Received: 01/14/2019] [Revised: 01/04/2020] [Accepted: 01/07/2020] [Indexed: 11/11/2022]
Abstract
Modern humans have the longest Achilles tendon (AT) of all the living primates. It has been proposed that this anatomy increases locomotor efficiency and that its elongation may have played a crucial role in the origin and early evolution of the genus Homo. Unfortunately, determining the length of the AT in extinct hominins has been difficult as tendons do not fossilize. Several methods have been proposed for estimating the length of the AT from calcaneal morphology, but the results have been inconclusive. This study tested the relationship between the area of the superior calcaneal facet and AT length in extant primates. The superior facet is instructive because it anchors the retrocalcaneal bursa, a soft tissue structure which helps to reduce friction between the AT and the calcaneus. Calcanei from 145 extant anthropoid primates from 12 genera were photographed in posterior view and the relative superior facet size quantified. AT lengths were obtained from published sources. The relative area of the superior facet is predictive of AT length in primates (R2 = 0.83; p < .001) and differs significantly between the great apes and humans (p < 0.001). When applied to fossil Australopithecus calcanei, our results suggest that australopiths possessed a longer, more human-like, AT than previously thought. These findings have important implications for the locomotor capabilities of Australopithecus, including their capacity for endurance running and climbing.
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Affiliation(s)
- Ellison J McNutt
- Department of Integrative Anatomical Sciences, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Jeremy M DeSilva
- Department of Anthropology, Dartmouth College, Hanover, New Hampshire, USA
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10
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Friedl L, Claxton AG, Walker CS, Churchill SE, Holliday TW, Hawks J, Berger LR, DeSilva JM, Marchi D. Femoral neck and shaft structure in Homo naledi from the Dinaledi Chamber (Rising Star System, South Africa). J Hum Evol 2019; 133:61-77. [PMID: 31358184 DOI: 10.1016/j.jhevol.2019.06.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [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: 12/22/2018] [Revised: 06/04/2019] [Accepted: 06/05/2019] [Indexed: 01/27/2023]
Abstract
The abundant femoral assemblage of Homo naledi found in the Dinaledi Chamber provides a unique opportunity to test hypotheses regarding the taxonomy, locomotion, and loading patterns of this species. Here we describe neck and shaft cross-sectional structure of all the femoral fossils recovered in the Dinaledi Chamber and compare them to a broad sample of fossil hominins, recent humans, and extant apes. Cross-sectional geometric (CSG) properties from the femoral neck (base of neck and midneck) and diaphysis (subtrochanteric region and midshaft) were obtained through CT scans for H. naledi and through CT scans or from the literature for the comparative sample. The comparison of CSG properties of H. naledi and the comparative samples shows that H. naledi femoral neck is quite derived with low superoinferior cortical thickness ratio and high relative cortical area. The neck appears superoinferiorly elongated because of two bony pilasters on its superior surface. Homo naledi femoral shaft shows a relatively thick cortex compared to the other hominins. The subtrochanteric region of the diaphysis is mediolaterally elongated resembling early hominins while the midshaft is anteroposteriorly elongated, indicating high mobility levels. In term of diaphyseal robusticity, the H. naledi femur is more gracile that other hominins and most apes. Homo naledi shows a unique combination of characteristics in its femur that undoubtedly indicate a species committed to terrestrial bipedalism but with a unique loading pattern of the femur possibly consequence of the unique postcranial anatomy of the species.
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Affiliation(s)
- Lukas Friedl
- Department of Anthropology, University of West Bohemia, Plzeň, Czech Republic
| | - Alex G Claxton
- Department of Anthropology, Dartmouth College, 409 Silsby, HB 6047, Hanover, USA
| | - Christopher S Walker
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, 1060 William Moore Drive, Raleigh, NC, 27607, USA; 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, 04 Bio Sci Bldg, Durham, NC, 27708, USA
| | - Steven E Churchill
- Department of Evolutionary Anthropology, Duke University, 04 Bio Sci Bldg, Durham, NC, 27708, USA; Evolutionary Studies Institute and Centre for Excellence in PalaeoSciences, University of the Witwatersrand, Private Bag 3, Wits, 2050, South Africa
| | - Trenton W Holliday
- Department of Anthropology, Tulane University, 417 Dinwiddie Hall, New Orleans, LA, 70118, USA; Evolutionary Studies Institute and Centre for Excellence in PalaeoSciences, University of the Witwatersrand, Private Bag 3, Wits, 2050, South Africa
| | - John Hawks
- Department of Anthropology, University of Wisconsin, 5325 Sewell Social Science Building, Madison, WI, 53706, USA; Evolutionary Studies Institute and Centre for Excellence in PalaeoSciences, University of the Witwatersrand, Private Bag 3, Wits, 2050, South Africa
| | - Lee R Berger
- Evolutionary Studies Institute and Centre for Excellence in PalaeoSciences, University of the Witwatersrand, Private Bag 3, Wits, 2050, South Africa
| | - Jeremy M DeSilva
- Department of Anthropology, Dartmouth College, 409 Silsby, HB 6047, Hanover, USA; Evolutionary Studies Institute and Centre for Excellence in PalaeoSciences, University of the Witwatersrand, Private Bag 3, Wits, 2050, South Africa
| | - Damiano Marchi
- Department of Biology, University of Pisa, vis Derna 1, Pisa, 56126, Italy; Evolutionary Studies Institute and Centre for Excellence in PalaeoSciences, University of the Witwatersrand, Private Bag 3, Wits, 2050, South Africa.
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11
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Walker CS, Cofran ZD, Grabowski M, Marchi D, Cook RW, Churchill SE, Tommy KA, Throckmorton Z, Ross AH, Hawks J, Yapuncich GS, Van Arsdale AP, Rentzeperis FI, Berger LR, DeSilva JM. Morphology of the Homo naledi femora from Lesedi. Am J Phys Anthropol 2019; 170:5-23. [PMID: 31228254 DOI: 10.1002/ajpa.23877] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 05/26/2019] [Accepted: 05/27/2019] [Indexed: 11/07/2022]
Abstract
OBJECTIVES The femoral remains recovered from the Lesedi Chamber are among the most complete South African fossil hominin femora discovered to date and offer new and valuable insights into the anatomy and variation of the bone in Homo naledi. While the femur is one of the best represented postcranial elements in the H. naledi assemblage from the Dinaledi Chamber, the fragmentary and commingled nature of the Dinaledi femoral remains has impeded the assessment of this element in its complete state. MATERIALS AND METHODS Here we analyze and provide descriptions of three new relatively well-preserved femoral specimens of H. naledi from the Lesedi Chamber: U.W. 102a-001, U.W. 102a-003, and U.W. 102a-004. These femora are quantitatively and qualitatively compared to multiple extinct hominin femoral specimens, extant hominid taxa, and, where possible, each other. RESULTS The Lesedi femora are morphologically similar to the Dinaledi femora for all overlapping regions, with differences limited to few traits of presently unknown significance. The Lesedi distal femur and mid-diaphysis preserve anatomy previously unidentified or unconfirmed in the species, including an anteroposteriorly expanded midshaft and anteriorly expanded patellar surface. The hypothesis that the Lesedi femoral sample may represent two individuals is supported. DISCUSSION The Lesedi femora increase the range of variation of femoral morphology in H. naledi. Newly described features of the diaphysis and distal femur are either taxonomically uninformative or Homo-like. Overall, these three new femora are consistent with previous functional interpretations of the H. naledi lower limb as belonging to a species adapted for long distance walking and, possibly, running.
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Affiliation(s)
- Christopher S Walker
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina.,Department of Evolutionary Anthropology, Duke University, Durham, North Carolina.,Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa
| | - Zachary D Cofran
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa.,Anthropology Department, Vassar College, Poughkeepsie, New York
| | - Mark Grabowski
- Research Centre in Evolutionary Anthropology and Palaeoecology, School of Natural Sciences and Psychology, Liverpool John Moores University, Liverpool, UK
| | - Damiano Marchi
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa.,Department of Biology, University of Pisa, Pisa, Italy
| | - Rebecca W Cook
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina.,Department of Evolutionary Anthropology, Duke University, Durham, North Carolina
| | - Steven E Churchill
- Department of Evolutionary Anthropology, Duke University, Durham, North Carolina.,Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa
| | - Kimberleigh A Tommy
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa.,Human Variation and Identification Research Unit, School of Anatomical Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Zachary Throckmorton
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa.,Department of Anatomy, Arkansas College of Osteopathic Medicine, Fort Smith, Arkansas
| | - Ann H Ross
- Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina
| | - John Hawks
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa.,Department of Anthropology, University of Wisconsin, Madison, Wisconsin
| | - Gabriel S Yapuncich
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina.,Department of Evolutionary Anthropology, Duke University, Durham, North Carolina
| | | | | | - Lee R Berger
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa
| | - Jeremy M DeSilva
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa.,Department of Anthropology, Dartmouth College, Hanover, New Hampshire
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12
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McNutt EJ, Zipfel B, DeSilva JM. The evolution of the human foot. Evol Anthropol 2018; 27:197-217. [DOI: 10.1002/evan.21713] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2017] [Revised: 04/20/2018] [Accepted: 05/30/2018] [Indexed: 11/07/2022]
Affiliation(s)
- Ellison J. McNutt
- Department of Anthropology; Dartmouth College; Hanover New Hampshire
- Ecology, Evolution, Ecosystems, and Society; Dartmouth College; Hanover New Hampshire
| | - Bernhard Zipfel
- Evolutionary Studies Institute and School of Geosciences; University of the Witwatersrand; Johannesburg South Africa
| | - Jeremy M. DeSilva
- Department of Anthropology; Dartmouth College; Hanover New Hampshire
- Evolutionary Studies Institute and School of Geosciences; University of the Witwatersrand; Johannesburg South Africa
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13
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Boyle EK, McNutt EJ, Sasaki T, Suwa G, Zipfel B, DeSilva JM. A quantification of calcaneal lateral plantar process position with implications for bipedal locomotion in Australopithecus. J Hum Evol 2018; 123:24-34. [PMID: 30075872 DOI: 10.1016/j.jhevol.2018.05.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [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: 09/01/2017] [Revised: 05/23/2018] [Accepted: 05/24/2018] [Indexed: 11/25/2022]
Abstract
The evolution of bipedalism in the hominin lineage has shaped the posterior human calcaneus into a large, robust structure considered to be adaptive for dissipating peak compressive forces and energy during heel-strike. A unique anatomy thought to contribute to the human calcaneus and its function is the lateral plantar process (LPP). While it has long been known that humans possess a plantarly positioned LPP and apes possess a more dorsally positioned homologous structure, the relative position of the LPP and intraspecific variation of this structure have never been quantified. Here, we present a method for quantifying relative LPP position and find that, while variable, humans have a significantly more plantar position of the LPP than that found in the apes. Among extinct hominins, while the position of the LPP in Australopithecus afarensis falls within the human distribution, the LPP is more dorsally positioned in Australopithecus sediba and barely within the modern human range of variation. Results from a resampling procedure suggest that these differences can reflect either individual variation of a foot structure/function largely shared among Australopithecus species, or functionally distinct morphologies that reflect locomotor diversity in Plio-Pleistocene hominins. An implication of the latter possibility is that calcaneal changes adaptive for heel-striking bipedalism may have evolved independently in two different hominin lineages.
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Affiliation(s)
- Eve K Boyle
- Center for the Advanced Study of Human Paleobiology, Department of Anthropology, The George Washington University, 800 22nd St. NW, Suite 6000, Washington, DC 20052, USA.
| | - Ellison J McNutt
- Department of Anthropology, Dartmouth College, Hanover, NH 03755, USA; Ecology, Evolution, Ecosystems, and Society, Dartmouth College, Hanover, NH 03755, USA
| | - Tomohiko Sasaki
- The University Museum, The University of Tokyo, Tokyo, Japan
| | - Gen Suwa
- The University Museum, The University of Tokyo, Tokyo, Japan
| | - Bernhard Zipfel
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa; School of Geosciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Jeremy M DeSilva
- Department of Anthropology, Dartmouth College, Hanover, NH 03755, USA; Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa
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14
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DeSilva JM, Gill CM, Prang TC, Bredella MA, Alemseged Z. A nearly complete foot from Dikika, Ethiopia and its implications for the ontogeny and function of Australopithecus afarensis. Sci Adv 2018; 4:eaar7723. [PMID: 29978043 PMCID: PMC6031372 DOI: 10.1126/sciadv.aar7723] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 05/22/2018] [Indexed: 05/21/2023]
Abstract
The functional and evolutionary implications of primitive retentions in early hominin feet have been under debate since the discovery of Australopithecus afarensis. Ontogeny can provide insight into adult phenotypes, but juvenile early hominin foot fossils are exceptionally rare. We analyze a nearly complete, 3.32-million-year-old juvenile foot of A. afarensis (DIK-1-1f). We show that juvenile A. afarensis individuals already had many of the bipedal features found in adult specimens. However, they also had medial cuneiform traits associated with increased hallucal mobility and a more gracile calcaneal tuber, which is unexpected on the basis of known adult morphologies. Selection for traits functionally associated with juvenile pedal grasping may provide a new perspective on their retention in the more terrestrial adult A. afarensis.
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Affiliation(s)
- Jeremy M. DeSilva
- Department of Anthropology, Dartmouth College, Hanover, NH 03755, USA
- Corresponding author. (J.M.D.); (Z.A.)
| | - Corey M. Gill
- Department of Anthropology, Boston University, Boston, MA 02215, USA
- Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
- Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Thomas C. Prang
- Center for the Study of Human Origins, Department of Anthropology, New York University, New York, NY 10003, USA
- New York Consortium in Evolutionary Anthropology, New York, NY, USA
| | - Miriam A. Bredella
- Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - Zeresenay Alemseged
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL 60637, USA
- Corresponding author. (J.M.D.); (Z.A.)
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15
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DeSilva JM. Comment on “The growth pattern of Neandertals, reconstructed from a juvenile skeleton from El Sidrón (Spain)”. Science 2018; 359:359/6380/eaar3611. [DOI: 10.1126/science.aar3611] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Accepted: 01/17/2018] [Indexed: 11/02/2022]
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16
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Abstract
The pelvis is an anatomically complex and functionally informative bone that contributes directly to both human locomotion and obstetrics. Because of the pelvis' important role in obstetrics, it is one of the most sexually dimorphic bony elements of the human body. The complex intersection of pelvic dimorphism, locomotion, and obstetrics has been reenergized by exciting new research, and many papers in this special issue of the pelvis help provide clarity on the relationship between pelvic form (especially female) and locomotor function. Compared to the pelvis of our ape relatives, the human pelvis is uniquely shaped; it is superoinferiorly short and stout, and mediolaterally wide-critical adaptations for bipedalism that are already present in some form very early in the history of the hominin lineage. In this issue, 13 original research papers address the anatomy, development, variation, and function of the modern human pelvis, with implications for understanding the selection pressures that shaped and continue to shape this bone. This rich collection of scholarship moves our understanding of the pelvis forward, while raising dozens of new questions that we hope will serve as inspiration for colleagues and students (both current and future) puzzled by this fascinatingly complex bone. Anat Rec, 300:628-632, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Jeremy M DeSilva
- Department of Anthropology, Dartmouth College, Hanover, New Hampshire, 03755
| | - Karen R Rosenberg
- Department of Anthropology, University of Delaware, Newark, Delaware, 19716
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17
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Abstract
No bone in the human postcranial skeleton differs more dramatically from its match in an ape skeleton than the pelvis. Humans have evolved a specialized pelvis, well-adapted for the rigors of bipedal locomotion. Precisely how this happened has been the subject of great interest and contention in the paleoanthropological literature. In part, this is because of the fragility of the pelvis and its resulting rarity in the human fossil record. However, new discoveries from Miocene hominoids and Plio-Pleistocene hominins have reenergized debates about human pelvic evolution and shed new light on the competing roles of bipedal locomotion and obstetrics in shaping pelvic anatomy. In this issue, 13 papers address the evolution of the human pelvis. Here, we summarize these new contributions to our understanding of pelvic evolution, and share our own thoughts on the progress the field has made, and the questions that still remain. Anat Rec, 300:789-797, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Karen R Rosenberg
- Department of Anthropology, University of Delaware, Newark, Delaware
| | - Jeremy M DeSilva
- Department of Anthropology, Dartmouth College, Hanover, New Hampshire
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18
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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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19
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DeSilva JM, Laudicina NM, Rosenberg KR, Trevathan WR. Neonatal Shoulder Width Suggests a Semirotational, Oblique Birth Mechanism inAustralopithecus afarensis. Anat Rec (Hoboken) 2017; 300:890-899. [DOI: 10.1002/ar.23573] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Accepted: 12/20/2016] [Indexed: 11/08/2022]
Affiliation(s)
- Jeremy M. DeSilva
- Department of Anthropology; Dartmouth College; Hanover New Hampshire 03755
| | | | - Karen R. Rosenberg
- Department of Anthropology; University of Delaware; Newark Delaware 19716
| | - Wenda R. Trevathan
- Department of Anthropology; New Mexico State University; Las Cruces New Mexico 88003
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20
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Claxton AG, Hammond AS, Romano J, Oleinik E, DeSilva JM. Virtual reconstruction of the Australopithecus africanus pelvis Sts 65 with implications for obstetrics and locomotion. J Hum Evol 2016; 99:10-24. [DOI: 10.1016/j.jhevol.2016.06.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Revised: 03/05/2016] [Accepted: 06/03/2016] [Indexed: 11/28/2022]
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21
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Gill SV, Keimig S, Kelty-Stephen D, Hung YC, DeSilva JM. The relationship between foot arch measurements and walking parameters in children. BMC Pediatr 2016; 16:15. [PMID: 26803747 PMCID: PMC4724397 DOI: 10.1186/s12887-016-0554-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 01/20/2016] [Indexed: 11/19/2022] Open
Abstract
Background Walking mechanics are influenced by body morphology. Foot arch height is one aspect of body morphology central to walking. However, generalizations about the relationship between arch height and walking are limited due to previous methodologies used for measuring the arch and the populations that have been studied. To gain the knowledge needed to support healthy gait in children and adults, we need to understand this relationship in unimpaired, typically developing children and adults using dynamic measures. The purpose of the current study was to examine the relationship between arch height and gait in a sample of healthy children and adults using dynamic measures. Methods Data were collected from 638 participants (n = 254 children and n = 384 adults) at the Museum of Science, Boston (MOS) and from 18 4- to 8-year-olds at the Motor Development and Motor Control Laboratories. Digital footprints were used to calculate two arch indices: the Chippaux-Smirak (CSI) and the Keimig Indices (KI). The height of the navicular bone was measured. Gait parameters were captured with a mechanized gait carpet at the MOS and three-dimensional motion analyses and in-ground force plates in the Motor Development and Motor Control Laboratories. Results Linear regression analyses on data from the MOS confirmed that as age increases, step length increases. With a linear mixed effect regression model, we found that individuals who took longer steps had higher arches as measured by the KI. However, this relationship was no longer significant when only adults were included in the model. A model restricted to children found that amongst this sample, those with higher CSI and higher KI values take longer relative step lengths. Data from the Motor Development and Motor Control Laboratories showed that both CSI and KI added to the prediction; children with lower anterior ground reaction forces had higher CSI and higher KI values. Arch height indices were correlated with navicular height. Conclusions These results suggest that more than one measure of the arch may be needed elucidate the relationship between arch height and gait. Electronic supplementary material The online version of this article (doi:10.1186/s12887-016-0554-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Simone V Gill
- Department of Occupational Therapy, Boston University, 635 Commonwealth Avenue, Boston, MA, 02215, USA. .,Boston University Program in Rehabilitation Sciences, 635 Commonwealth Avenue, Boston, MA, 02215, USA. .,Department of Medicine, Boston University Medical Center, 635 Commonwealth Avenue, Boston, MA, 02215, USA.
| | - Sara Keimig
- Department of Anthropology, Boston University, 635 Commonwealth Avenue, Boston, MA, 02215, USA
| | | | - Ya-Ching Hung
- Department of Family, Nutrition, and Exercise Sciences, Queens College, New York, USA
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22
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Gill CM, Bredella MA, DeSilva JM. Skeletal development of hallucal tarsometatarsal joint curvature and angulation in extant apes and modern humans. J Hum Evol 2015; 88:137-145. [DOI: 10.1016/j.jhevol.2015.07.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2014] [Revised: 06/01/2015] [Accepted: 07/13/2015] [Indexed: 11/26/2022]
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23
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Harcourt-Smith WEH, Throckmorton Z, Congdon KA, Zipfel B, Deane AS, Drapeau MSM, Churchill SE, Berger LR, DeSilva JM. The foot of Homo naledi. Nat Commun 2015; 6:8432. [PMID: 26439101 PMCID: PMC4600720 DOI: 10.1038/ncomms9432] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [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: 11/21/2022] Open
Abstract
Modern humans are characterized by a highly specialized foot that reflects our obligate bipedalism. Our understanding of hominin foot evolution is, although, hindered by a paucity of well-associated remains. Here we describe the foot of Homo naledi from Dinaledi Chamber, South Africa, using 107 pedal elements, including one nearly-complete adult foot. The H. naledi foot is predominantly modern human-like in morphology and inferred function, with an adducted hallux, an elongated tarsus, and derived ankle and calcaneocuboid joints. In combination, these features indicate a foot well adapted for striding bipedalism. However, the H. naledi foot differs from modern humans in having more curved proximal pedal phalanges, and features suggestive of a reduced medial longitudinal arch. Within the context of primitive features found elsewhere in the skeleton, these findings suggest a unique locomotor repertoire for H. naledi, thus providing further evidence of locomotor diversity within both the hominin clade and the genus Homo. Hominin fossils reveal high diversity in the types of terrestrial bipedalism. Here, the authors show that the foot of Homo naledi from South Africa is predominantly human-like in morphology and inferred function and is well adapted for striding bipedalism.
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Affiliation(s)
- W E H Harcourt-Smith
- Department of Anthropology, Lehman College CUNY, 250 Bedford Park Boulevard W, Bronx, New York 10468, USA.,Division of Paleontology, American Museum of Natural History, CPW @ W. 79th Street, New York, New York 10024, USA.,Department of Anthropology, City University of New York Graduate Center, 365 5th Avenue, New York, New York 10016, USA.,Evolutionary Studies Institute and Centre for Excellence in Palaeosciences, University of the Witwatersrand, Private Bag 3, Wits, Johannesburg 2050, South Africa
| | - Z Throckmorton
- Evolutionary Studies Institute and Centre for Excellence in Palaeosciences, University of the Witwatersrand, Private Bag 3, Wits, Johannesburg 2050, South Africa.,Department of Anatomy, DeBusk College of Osteopathic Medicine, Lincoln Memorial University, Harrogate, Tennessee 37724, USA
| | - K A Congdon
- Evolutionary Studies Institute and Centre for Excellence in Palaeosciences, University of the Witwatersrand, Private Bag 3, Wits, Johannesburg 2050, South Africa.,Department of Biology, Southern Utah University, 351W Center Street, Cedar City, Utah 84720, USA
| | - B Zipfel
- Evolutionary Studies Institute and Centre for Excellence in Palaeosciences, University of the Witwatersrand, Private Bag 3, Wits, Johannesburg 2050, South Africa
| | - A S Deane
- Evolutionary Studies Institute and Centre for Excellence in Palaeosciences, University of the Witwatersrand, Private Bag 3, Wits, Johannesburg 2050, South Africa.,Department of Anatomy and Neurobiology, University of Kentucky College of Medicine, MN 224 UK Medical Center, Lexington, Kemtucky 40536, USA
| | - M S M Drapeau
- Evolutionary Studies Institute and Centre for Excellence in Palaeosciences, University of the Witwatersrand, Private Bag 3, Wits, Johannesburg 2050, South Africa.,Department of Anthropology, Université de Montréal, C.P. 6128, Succ. Centre-ville, Montréal, Quebec H3C 3J7, Canada
| | - S E Churchill
- Evolutionary Studies Institute and Centre for Excellence in Palaeosciences, University of the Witwatersrand, Private Bag 3, Wits, Johannesburg 2050, South Africa.,Department of Evolutionary Anthropology, Duke University, 104 Biological Sciences Building, Box 90383, Durham, North Carolina 27708, USA
| | - L R Berger
- Evolutionary Studies Institute and Centre for Excellence in Palaeosciences, University of the Witwatersrand, Private Bag 3, Wits, Johannesburg 2050, South Africa
| | - J M DeSilva
- Evolutionary Studies Institute and Centre for Excellence in Palaeosciences, University of the Witwatersrand, Private Bag 3, Wits, Johannesburg 2050, South Africa.,Department of Anthropology, Dartmouth College, Hanover, New Hampshire 03775, USA.,Department of Anthropology, Boston University, 232 Bay State Road, Boston, Massachusetts 02215, USA
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24
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Gill SV, Vessali M, Pratt JA, Watts S, Pratt JS, Raghavan P, DeSilva JM. The Importance of Interdisciplinary Research Training and Community Dissemination. Clin Transl Sci 2015; 8:611-4. [PMID: 26508528 DOI: 10.1111/cts.12330] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [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: 11/28/2022] Open
Abstract
Funding agencies and institutions are creating initiatives to encourage interdisciplinary research that can be more easily translated into community initiatives to enhance health. Therefore, the current research environment calls for interdisciplinary education and skills to create sustained partnerships with community institutions. However, formalized opportunities in both of these areas are limited for students embarking on research careers. The purpose of this paper is to underscore the historical and current importance of providing interdisciplinary training and community dissemination for research students. We also suggest an approach to begin to address the existing gap. Specifically, we suggest embedding a 10-week summer rotation into existing research curricula with the goals of: (1) providing students with a hands-on interdisciplinary research experience, (2) facilitating dialogue between research students and community settings to disseminate science to the public, and (3) sparking collaborations among researchers who seek to create a way to sustain summer program rotations with grant funding.
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Affiliation(s)
- Simone V Gill
- Department of Occupational Therapy, Boston University, Boston, Massachusetts, USA
| | - Misha Vessali
- Department of Occupational Therapy, Boston University, Boston, Massachusetts, USA
| | - Jacob A Pratt
- Department of Occupational Therapy, Boston University, Boston, Massachusetts, USA
| | - Samantha Watts
- Department of Occupational Therapy, Boston University, Boston, Massachusetts, USA
| | - Janey S Pratt
- Department of Surgery, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Preeti Raghavan
- Rehabilitation Medicine, NYU Langone Medical Center, New York, New York, USA
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25
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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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Cofran Z, DeSilva JM. A neonatal perspective on Homo erectus brain growth. J Hum Evol 2015; 81:41-7. [DOI: 10.1016/j.jhevol.2015.02.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Revised: 02/15/2015] [Accepted: 02/17/2015] [Indexed: 10/23/2022]
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Gill CM, Taneja AK, Bredella MA, Torriani M, DeSilva JM. Osteogenic relationship between the lateral plantar process and the peroneal tubercle in the human calcaneus. J Anat 2013; 224:173-9. [PMID: 24188397 DOI: 10.1111/joa.12135] [Citation(s) in RCA: 5] [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] [Accepted: 10/09/2013] [Indexed: 12/17/2022] Open
Abstract
The osteogenic relationship between the lateral plantar process and the peroneal tubercle has been an uncertainty for researchers over several decades. While some argue there to be no developmental relationship between these two calcaneal structures, others have suggested that there is an inverse relationship, the lateral plantar process forming from a part of the peroneal tubercle. However, no previous studies have offered quantitative measurements to test these hypotheses. In this study, we measured the size of the peroneal tubercle, retrotrochlear eminence, and the size and area of the lateral plantar process in 73 subjects using magnetic resonance imaging (MRI). Navicular height was measured using weight-bearing radiographs as a measurement of longitudinal arch in 35 of these subjects. Age, body mass, and body mass index (BMI) were also recorded for all subjects. We determined that there was a significant positive correlation between the lateral plantar process and size of the peroneal tubercle, body mass, and BMI. Thus, assertions that there is an inverse relationship between the size of the lateral plantar process and the peroneal tubercle are here unfounded. We also determined there to be a positive correlation between the peroneal tubercle and both the size of the retrotrochlear eminence and the height of the navicular. In conclusion, we relate these novel findings to hominin fossil calcanei and discuss the evolutionary and biomechanical implications.
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Affiliation(s)
- Corey M Gill
- Department of Musculoskeletal Imaging and Intervention, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA; Department of Anthropology, Boston University, Boston, MA, USA
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Wells JCK, DeSilva JM, Stock JT. The obstetric dilemma: an ancient game of Russian roulette, or a variable dilemma sensitive to ecology? Am J Phys Anthropol 2012; 149 Suppl 55:40-71. [PMID: 23138755 DOI: 10.1002/ajpa.22160] [Citation(s) in RCA: 154] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The difficult birth process of humans, often described as the "obstetric dilemma," is commonly assumed to reflect antagonistic selective pressures favoring neonatal encephalization and maternal bipedal locomotion. However, cephalo-pelvic disproportion is not exclusive to humans, and is present in some primate species of smaller body size. The fossil record indicates mosaic evolution of the obstetric dilemma, involving a number of different evolutionary processes, and it appears to have shifted in magnitude between Australopithecus, Pleistocene Homo, and recent human populations. Most attention to date has focused on its generic nature, rather than on its variability between populations. We re-evaluate the nature of the human obstetric dilemma using updated hominin and primate literature, and then consider the contribution of phenotypic plasticity to variability in its magnitude. Both maternal pelvic dimensions and fetal growth patterns are sensitive to ecological factors such as diet and the thermal environment. Neonatal head girth has low plasticity, whereas neonatal mass and maternal stature have higher plasticity. Secular trends in body size may therefore exacerbate or decrease the obstetric dilemma. The emergence of agriculture may have exacerbated the dilemma, by decreasing maternal stature and increasing neonatal growth and adiposity due to dietary shifts. Paleodemographic comparisons between foragers and agriculturalists suggest that foragers have considerably lower rates of perinatal mortality. In contemporary populations, maternal stature remains strongly associated with perinatal mortality in many populations. Long-term improvements in nutrition across future generations may relieve the dilemma, but in the meantime, variability in its magnitude is likely to persist.
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Affiliation(s)
- Jonathan C K Wells
- Childhood Nutrition Research Centre, UCL Institute of Child Health, London WC1N 1EH, UK.
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DeSilva JM, Proctor DJ, Zipfel B. A complete second metatarsal (StW 89) from Sterkfontein Member 4, South Africa. J Hum Evol 2012; 63:487-96. [DOI: 10.1016/j.jhevol.2012.05.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2011] [Revised: 05/15/2012] [Accepted: 05/15/2012] [Indexed: 11/26/2022]
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DeSilva JM, Devlin MJ. A comparative study of the trabecular bony architecture of the talus in humans, non-human primates, and Australopithecus. J Hum Evol 2012; 63:536-51. [PMID: 22840715 DOI: 10.1016/j.jhevol.2012.06.006] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2012] [Revised: 06/26/2012] [Accepted: 06/26/2012] [Indexed: 11/24/2022]
Abstract
This study tested the hypothesis that talar trabecular microarchitecture reflects the loading patterns in the primate ankle joint, to determine whether talar trabecular morphology might be useful for inferring locomotor behavior in fossil hominins. Trabecular microarchitecture was quantified in the anteromedial, anterolateral, posteromedial, and posterolateral quadrants of the talar body in humans and non-human primates using micro-computed tomography. Trabecular bone parameters, including bone volume fraction, trabecular number and thickness, and degree of anisotropy differed between primates, but not in a manner entirely consistent with hypotheses derived from locomotor kinematics. Humans have highly organized trabecular struts across the entirety of the talus, consistent with the compressive loads incurred during bipedal walking. Chimpanzees possess a high bone volume fraction, consisting of plate-like trabecular struts. Orangutan tali are filled with a high number of thin, connected trabeculae, particularly in the anterior portion of the talus. Gorillas and baboons have strikingly similar internal architecture of the talus. Intraspecific analyses revealed no regional differences in trabecular architecture unique to bipedal humans. Of the 22 statistically significant regional differences in the human talus, all can also be found in other primates. Trabecular thickness, number, spacing, and connectivity density had the same regional relationship in the talus of humans, chimpanzees, gorillas, and baboons, suggesting a deeply conserved architecture in the primate talus. Australopithecus tali are human-like in most respects, differing most notably in having more oriented struts in the posteromedial quadrant of the body compared with the posterolateral quadrant. Though this result could mean that australopiths loaded their ankles in a unique manner during bipedal gait, the regional variation in degree of anisotropy was similar in humans, chimpanzees, and gorillas. These results collectively suggest that the microarchitecture of the talus does not simply reflect the loading environment, limiting its utility in reconstructing locomotion in fossil primates.
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Affiliation(s)
- Jeremy M DeSilva
- Department of Anthropology, Boston University, Boston, MA 02215, USA.
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Abstract
A well-preserved and articulated partial foot and ankle of Australopithecus sediba, including an associated complete adult distal tibia, talus, and calcaneus, have been discovered at the Malapa site, South Africa, and reported in direct association with the female paratype Malapa Hominin 2. These fossils reveal a mosaic of primitive and derived features that are distinct from those seen in other hominins. The ankle (talocrural) joint is mostly humanlike in form and inferred function, and there is some evidence for a humanlike arch and Achilles tendon. However, Au. sediba is apelike in possessing a more gracile calcaneal body and a more robust medial malleolus than expected. These observations suggest, if present models of foot function are correct, that Au. sediba may have practiced a unique form of bipedalism and some degree of arboreality. Given the combination of features in the Au. sediba foot, as well as comparisons between Au. sediba and older hominins, homoplasy is implied in the acquisition of bipedal adaptations in the hominin foot.
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Affiliation(s)
- Bernhard Zipfel
- Institute for Human Evolution, University of the Witwatersrand, Post Office Wits, 2050 Wits, South Africa.
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DeSilva JM, Throckmorton ZJ. Lucy's flat feet: the relationship between the ankle and rearfoot arching in early hominins. PLoS One 2010; 5:e14432. [PMID: 21203433 PMCID: PMC3010983 DOI: 10.1371/journal.pone.0014432] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [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: 07/23/2010] [Accepted: 12/01/2010] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND In the Plio-Pleistocene, the hominin foot evolved from a grasping appendage to a stiff, propulsive lever. Central to this transition was the development of the longitudinal arch, a structure that helps store elastic energy and stiffen the foot during bipedal locomotion. Direct evidence for arch evolution, however, has been somewhat elusive given the failure of soft-tissue to fossilize. Paleoanthropologists have relied on footprints and bony correlates of arch development, though little consensus has emerged as to when the arch evolved. METHODOLOGY/PRINCIPAL FINDINGS Here, we present evidence from radiographs of modern humans (n = 261) that the set of the distal tibia in the sagittal plane, henceforth referred to as the tibial arch angle, is related to rearfoot arching. Non-human primates have a posteriorly directed tibial arch angle, while most humans have an anteriorly directed tibial arch angle. Those humans with a posteriorly directed tibial arch angle (8%) have significantly lower talocalcaneal and talar declination angles, both measures of an asymptomatic flatfoot. Application of these results to the hominin fossil record reveals that a well developed rearfoot arch had evolved in Australopithecus afarensis. However, as in humans today, Australopithecus populations exhibited individual variation in foot morphology and arch development, and "Lucy" (A.L. 288-1), a 3.18 Myr-old female Australopithecus, likely possessed asymptomatic flat feet. Additional distal tibiae from the Plio-Pleistocene show variation in tibial arch angles, including two early Homo tibiae that also have slightly posteriorly directed tibial arch angles. CONCLUSIONS/SIGNIFICANCE This study finds that the rearfoot arch was present in the genus Australopithecus. However, the female Australopithecus afarensis "Lucy" has an ankle morphology consistent with non-pathological flat-footedness. This study suggests that, as in humans today, there was variation in arch development in Plio-Pleistocene hominins.
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Affiliation(s)
- Jeremy M DeSilva
- Department of Anthropology, Boston University, Boston, Massachusetts, United States of America.
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DeSilva JM, Zipfel B, Van Arsdale AP, Tocheri MW. The Olduvai Hominid 8 foot: Adult or subadult? J Hum Evol 2010; 58:418-23. [DOI: 10.1016/j.jhevol.2010.03.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2009] [Revised: 03/05/2010] [Accepted: 03/08/2010] [Indexed: 10/19/2022]
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Abstract
The midtarsal break was first described in this journal nearly 75 years ago to explain the ability of non-human primates to lift their heel independently of the rest of the foot. Since the initial description of the midtarsal break, the calcaneocuboid joint has been assumed to be the anatomical source of this motion. Recently, however, it has been suggested that the midtarsal break may occur at the cuboid-metatarsal joint, rather than at the calcaneocuboid joint. Data compiled from X-rays, dissections, manual manipulation of living primate feet, video of captive catarrhines, and osteological specimens concur that the midtarsal break is a complex motion caused by dorsiflexion at both joints with the cuboid-metatarsal joint contributing roughly 2/3 of total midfoot dorsiflexion, and the calcaneocuboid joint only about 1/3 of total midfoot dorsiflexion. The convexity of the proximal articular surface of the fourth and fifth metatarsals and corresponding concave cuboid facets provide skeletal correlates for the presence of midfoot dorsiflexion at the cuboid-metatarsal joint. Study of hominin metatarsals from Australopithecus afarensis, A. africanus, Homo erectus, and the metatarsals and a cuboid from the OH 8 foot show little capacity for dorsiflexion at the cuboid-metatarsal joint. These results suggest that hominins may have already evolved a stable midfoot region well adapted for the push-off phase of bipedalism by at least 3.2 million years ago. These data illuminate the evolution of the longitudinal arch and show further evidence of constraints on the arboreal capacity in early hominins.
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DeSilva JM, Morgan ME, Barry JC, Pilbeam D. A hominoid distal tibia from the Miocene of Pakistan. J Hum Evol 2009; 58:147-54. [PMID: 20036414 DOI: 10.1016/j.jhevol.2009.11.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2009] [Revised: 10/27/2009] [Accepted: 11/04/2009] [Indexed: 11/16/2022]
Abstract
A distal tibia, YGSP 1656, from the early Late Miocene portion of the Chinji Formation in Pakistan is described. The fossil is 11.4 million years old and is one of only six postcranial elements now assigned to Sivapithecus indicus. Aspects of the articular surface are cercopithecoid-like, suggesting some pronograde locomotor activities. However, YGSP 1656 possesses an anteroposteriorly compressed metaphysis and a mediolaterally thick medial malleolus, ape-like features functionally related to orthograde body postures and vertical climbing. YGSP 1656 lacks specializations found in the ankle of terrestrial cercopithecoids and thus Sivapithecus may have been primarily arboreal. Nevertheless, the morphology of this tibia is unique, consistent with other interpretations of Sivapithecus postcranial functional morphology that suggest the locomotion of this ape lacks a modern analog. Based on the limited postcranial remains from S. indicus, we hypothesize that this taxon exhibited substantial body size dimorphism.
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Affiliation(s)
- Jeremy M DeSilva
- Department of Anthropology, Boston University, Boston, MA 02215, USA.
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Fajardo RJ, Cory E, Patel ND, Nazarian A, Laib A, Manoharan RK, Schmitz JE, DeSilva JM, MacLatchy LM, Snyder BD, Bouxsein ML. Specimen size and porosity can introduce error into microCT-based tissue mineral density measurements. Bone 2009; 44:176-84. [PMID: 18822398 PMCID: PMC4286574 DOI: 10.1016/j.bone.2008.08.118] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2008] [Revised: 08/13/2008] [Accepted: 08/19/2008] [Indexed: 12/17/2022]
Abstract
The accurate measurement of tissue mineral density, rho(m), in specimens of unequal size or quantities of bone mineral using polychromatic microCT systems is important, since studies often compare samples with a range of sizes and bone densities. We assessed the influence of object size on microCT measurements of rho(m) using (1) hydroxyapatite rods (HA), (2) precision-manufactured aluminum foams (AL) simulating trabecular bone structure, and (3) bovine cortical bone cubes (BCt). Two beam-hardening correction (BHC) algorithms, determined using a 200 and 1200 mg/cm(3) HA wedge phantom, were used to calculate rho(m) of the HA and BCt. The 200 mg/cm(3) and an aluminum BHC algorithm were used to calculate the linear attenuation coefficients of the AL foams. Equivalent rho(m) measurements of 500, 1000, and 1500 mg HA/cm(3) rods decreased (r(2)>0.96, p<0.05 for all) as HA rod diameter increased in the 200 mg/cm(3) BHC data. Errors averaged 8.2% across these samples and reached as high as 29.5%. Regression analyses suggested no size effects in the 1200 mg/cm(3) BHC data but differences between successive sizes still reached as high as 13%. The linear attenuation coefficients of the AL foams increased up to approximately 6% with increasing volume fractions (r(2)>0.81, p<0.05 for all) but the strength of the size-related error was also BHC dependent. Equivalent rho(m) values were inversely correlated with BCt cube size (r(2)>0.92, p<0.05). Use of the 1200 mg/cm(3) BHC ameliorated the size-related artifact compared to the 200 mg/cm(3) BHC but errors with this BHC were still significant and ranged between 5% and 12%. These results demonstrate that object size, structure, and BHC algorithm can influence microCT measurements of rho(m). Measurements of rho(m) of specimens of unequal size or quantities of bone mineral must be interpreted with caution unless appropriate steps are taken to minimize these potential artifacts.
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Affiliation(s)
- Roberto J Fajardo
- Orthopedic Biomechanics Laboratory, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA.
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