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Bleuze MM. Changes in limb bone diaphyseal structure in chimpanzees during development. AMERICAN JOURNAL OF BIOLOGICAL ANTHROPOLOGY 2024; 184:e24942. [PMID: 38602254 DOI: 10.1002/ajpa.24942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 02/24/2024] [Accepted: 04/02/2024] [Indexed: 04/12/2024]
Abstract
OBJECTIVES This study tests if femoral and humeral cross-sectional geometry (CSG) and cross-sectional properties (CSPs) in an ontogenetic series of wild-caught chimpanzees (Pan troglodytes ssp.) reflect locomotor behavior during development. The goal is to clarify the relationship between limb bone structure and locomotor behavior during ontogeny in Pan. MATERIALS AND METHODS The latex cast method was used to reconstruct cross sections at the midshaft femur and mid-distal humerus. Second moments of area (SMAs) (Ix, Iy, Imax, Imin), which are proportional to bending rigidity about a specified axis, and the polar SMA (J), which is proportional to average bending rigidity, were calculated at section locations. Cross-sectional shape (CSS) was assessed from Ix/Iy and Imax/Imin ratios. Juvenile and adult subsamples were compared. RESULTS Juveniles and adults have significantly greater femoral J compared to humeral J. Mean interlimb proportions of J are not significantly different between the groups. There is an overall decreasing trend in diaphyseal circularity between the juvenile phase of development and adulthood, although significant differences are only found in the humerus. DISCUSSION Juvenile chimpanzee locomotion includes forelimb- and hindlimb-biased behaviors. Juveniles and adults preferentially load their hindlimbs relative to their forelimbs. This may indicate similar locomotor behavior, although other explanations including a diversity of hindlimb-biased locomotor behaviors in juveniles cannot be ruled out. Different ontogenetic trends in forelimb and hindlimb CSS are consistent with limb bone CSG reflecting functional adaptation, albeit the complex nature of bone functional adaptation requires cautious interpretations of skeletal functional morphology from biomechanical analyses.
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Affiliation(s)
- Michele M Bleuze
- Institutional affiliation: Department of Anthropology, California State University Los Angeles, Los Angeles, California, USA
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2
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Harper CM, Patel BA. Trabecular bone variation in the gorilla calcaneus. AMERICAN JOURNAL OF BIOLOGICAL ANTHROPOLOGY 2024; 184:e24939. [PMID: 38631677 DOI: 10.1002/ajpa.24939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 02/15/2024] [Accepted: 04/02/2024] [Indexed: 04/19/2024]
Abstract
OBJECTIVES Calcaneal external shape differs among nonhuman primates relative to locomotion. Such relationships between whole-bone calcaneal trabecular structure and locomotion, however, have yet to be studied. Here we analyze calcaneal trabecular architecture in Gorilla gorilla gorilla, Gorilla beringei beringei, and G. b. graueri to investigate general trends and fine-grained differences among gorilla taxa relative to locomotion. MATERIALS AND METHODS Calcanei were micro-CT scanned. A three-dimensional geometric morphometric sliding semilandmark analysis was carried out and the final landmark configurations used to position 156 volumes of interest. Trabecular thickness (Tb.Th), trabecular spacing (Tb.Sp), and bone volume fraction (BV/TV) were calculated using the BoneJ plugin for ImageJ and MATLAB. Non-parametric MANOVAs were run to test for significant differences among taxa in parameter raw values and z-scores. Parameter distributions were visualized using color maps and summarized using principal components analysis. RESULTS There are no significant differences in raw BV/TV or Tb.Th among gorillas, however G. b. beringei significantly differs in z-scores for both parameters (p = <0.0271). All three taxa exhibit relatively lower BV/TV and Tb.Th in the posterior half of the calcaneus. This gradation is exacerbated in G. b. beringei. G. b. graueri significantly differs from other taxa in Tb.Sp z-scores (p < 0.001) indicating a different spacing distribution. DISCUSSION Relatively higher Tb.Th and BV/TV in the anterior calcaneus among gorillas likely reflects higher forces associated with body mass (transmitted through the subtalar joint) relative to forces transferred through the posterior calcaneus. The different Tb.Sp pattern in G. b. graueri may reflect proposed differences in foot positioning during locomotion.
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Affiliation(s)
- Christine M Harper
- Department of Biomedical Sciences, Cooper Medical School of Rowan University, Camden, New Jersey, USA
| | - Biren A Patel
- Department of Integrative Anatomical Sciences, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
- Human and Evolutionary Biology, Department of Biological Sciences, University of Southern California, Los Angeles, California, USA
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3
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Powell VCR, Barr WA, Hammond AS, Wood BA. Behavioral and phylogenetic correlates of limb length proportions in extant apes and monkeys: Implications for interpreting hominin fossils. J Hum Evol 2024; 190:103494. [PMID: 38564844 DOI: 10.1016/j.jhevol.2024.103494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 01/02/2024] [Accepted: 01/03/2024] [Indexed: 04/04/2024]
Abstract
The body proportions of extant animals help inform inferences about the behaviors of their extinct relatives, but relationships between body proportions, behavior, and phylogeny in extant primates remain unclear. Advances in behavioral data, molecular phylogenies, and multivariate analytical tools make it an opportune time to perform comprehensive comparative analyses of primate traditional limb length proportions (e.g., intermembral, humerofemoral, brachial, and crural indices), body size-adjusted long bone proportions, and principal components. In this study we used a mix of newly-collected and published data to investigate whether and how the limb length proportions of a diverse sample of primates, including monkeys, apes, and modern humans, are influenced by behavior and phylogeny. We reconfirm that the intermembral index, followed by the first principal component of traditional limb length proportions, is the single most effective variable distinguishing hominoids and other anthropoids. Combined limb length proportions and positional behaviors are strongly correlated in extant anthropoid groups, but phylogeny is a better predictor of limb length proportion variation than of behavior. We confirm convergences between members of the Atelidae and extant apes (especially Pan), members of the Hylobatidae and Pongo, and a potential divergence of Presbytis limb proportions from some other cercopithecoids, which correlate with adaptations for forelimb-dominated behaviors in some colobines. Collectively, these results substantiate hypotheses indicating that extinct hominins and other hominoid taxa can be distinguished by analyzing combinations of their limb length proportions at different taxonomic levels. From these results, we hypothesize that fossil skeletons characterized by notably disparate limb length proportions are unlikely to have exhibited similar behavioral patterns.
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Affiliation(s)
- Vance C R Powell
- Department of Anatomy, Howard University College of Medicine, 520 W St. N.W., Washington, D.C., 20059, USA; Center for the Advanced Study of Human Paleobiology, Department of Anthropology, The George Washington University, Washington, D.C., 20052, USA.
| | - W Andrew Barr
- Center for the Advanced Study of Human Paleobiology, Department of Anthropology, The George Washington University, Washington, D.C., 20052, USA
| | - Ashley S Hammond
- Division of Anthropology, American Museum of Natural History (AMNH), New York, N.Y., 10024, USA; New York Consortium in Evolutionary Primatology at AMNH, New York, N.Y., 10024, USA
| | - Bernard A Wood
- Center for the Advanced Study of Human Paleobiology, Department of Anthropology, The George Washington University, Washington, D.C., 20052, USA
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4
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Kralick AE, Zemel BS, Nolan C, Lin P, Tocheri MW. Relative leg-to-arm skeletal strength proportions in orangutans by species and sex. J Hum Evol 2024; 188:103496. [PMID: 38412694 DOI: 10.1016/j.jhevol.2024.103496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 01/02/2024] [Accepted: 01/05/2024] [Indexed: 02/29/2024]
Abstract
Among extant great apes, orangutans climb most frequently. However, Bornean orangutans (Pongo pygmaeus) exhibit higher frequencies of terrestrial locomotion than do Sumatran orangutans (Pongo abelii). Variation in long bone cross-sectional geometry is known to reflect differential loading of the limbs. Thus, Bornean orangutans should show greater relative leg-to-arm strength than their Sumatran counterparts. Using skeletal specimens from museum collections, we measured two cross-sectional geometric measures of bone strength: the polar section modulus (Zpol) and the ratio of maximum to minimum area moments of inertia (Imax/Imin), at the midshaft of long bones in Bornean (n = 19) and Sumatran adult orangutans (n = 12) using medical CT and peripheral quantitative CT scans, and compared results to published data of other great apes. Relative leg-to-arm strength was quantified using ratios of femur and tibia over humerus, radius, and ulna, respectively. Differences between orangutan species and between sexes in median ratios were assessed using Wilcoxon rank sum tests. The tibia of Bornean orangutans was stronger relative to the humerus and the ulna than in Sumatran orangutans (p = 0.008 and 0.025, respectively), consistent with behavioral studies that indicate higher frequencies of terrestrial locomotion in the former. In three Zpol ratios, adult female orangutans showed greater leg-to-arm bone strength compared to flanged males, which may relate to females using their legs more during arboreal locomotion than in adult flanged males. A greater amount of habitat discontinuity on Borneo compared to Sumatra has been posited as a possible explanation for observed interspecific differences in locomotor behaviors, but recent camera trap studies has called this into question. Alternatively, greater frequencies of terrestriality in Pongo pygmaeus may be due to the absence of tigers on Borneo. The results of this study are consistent with the latter explanation given that habitat continuity was greater a century ago when our study sample was collected.
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Affiliation(s)
- Alexandra E Kralick
- Studies of Women, Gender, and Sexuality, Harvard University, Cambridge, 02138, USA; Department of Anthropology, University of Pennsylvania, Philadelphia, Pennsylvania, 19104, USA.
| | - Babette S Zemel
- Division of Gastroenterology, Hepatology and Nutrition, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA; Department of Pediatrics, The University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104, USA
| | - Clara Nolan
- Fine Arts Department, University of Pennsylvania, Philadelphia, PA, 19104, USA; Department of Computer and Information Science, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Phillip Lin
- Stockdale High School, Bakersfield, CA, 93311, USA
| | - Matthew W Tocheri
- Department of Anthropology, Lakehead University, Thunder Bay, Ontario, P7B 5E1, Canada; Human Origins Program, National Museum of Natural History, Smithsonian Institution, Washington, D.C., 20013, USA; Australian Research Council Centre of Excellence for Australian Biodiversity and Heritage, University of Wollongong, Wollongong, New South Wales, NSW, 2522, Australia
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5
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Harper CM, Roach CS, Goldstein DM, Sylvester AD. Morphological variation of the Pan talus relative to that of Gorilla. AMERICAN JOURNAL OF BIOLOGICAL ANTHROPOLOGY 2023. [PMID: 37300336 DOI: 10.1002/ajpa.24796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 03/27/2023] [Accepted: 05/27/2023] [Indexed: 06/12/2023]
Abstract
OBJECTIVES Differences in talar articular morphology relative to locomotion have recently been found within Pan and Gorilla. Whole-bone talar morphology within, and shared variation among, Pan and Gorilla (sub)species, however, has yet to be investigated. Here we separately analyze talar external shape within Pan (P. t. troglodytes, P. t. schweinfurthii, P. t. verus, P. paniscus) and Gorilla (G. g. gorilla, G. b. beringei, G. b. graueri) relative to degree of arboreality and body size. Pan and Gorilla are additionally analyzed together to determine if consistent shape differences exist within the genera. MATERIALS AND METHODS Talar external shape was quantified using a weighted spherical harmonic analysis. Shape variation both within and among Pan and Gorilla was described using principal component analyses. Root mean square distances were calculated between taxon averages, and resampling statistics conducted to test for pairwise differences. RESULTS P. t. verus (most arboreal Pan) talar shape significantly differs from other Pan taxa (p < 0.05 for pairwise comparisons) driven by more asymmetrical trochlear rims and a medially-set talar head. P. t. troglodytes, P. t. schweinfurthii, and P. paniscus do not significantly differ (p > 0.05 for pairwise comparisons). All gorilla taxa exhibit significantly different talar morphologies (p < 0.007 for pairwise comparisons). The more terrestrial subspecies of G. beringei and P. troglodytes exhibit a superoinferiorly taller talar head/neck complex. DISCUSSION P. t. verus exhibits talar morphologies that have been previously related to more frequent arboreality. The adaptations in the more terrestrial G. beringei and P. troglodytes subspecies may serve to facilitate load transmission.
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Affiliation(s)
- Christine M Harper
- Department of Biomedical Sciences, Cooper Medical School of Rowan University, Camden, New Jersey, USA
| | - Caleigh S Roach
- Krieger School of Arts and Sciences, The Johns Hopkins University, Baltimore, Maryland, USA
| | - Deanna M Goldstein
- Department of Anatomical Sciences, Renaissance School of Medicine, Stony Brook University, Stony Brook, New York, USA
| | - Adam D Sylvester
- Center for Functional Anatomy and Evolution, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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6
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Sarringhaus L, Lewton KL, Iqbal S, Carlson KJ. Ape femoral-humeral rigidities and arboreal locomotion. AMERICAN JOURNAL OF BIOLOGICAL ANTHROPOLOGY 2022; 179:624-639. [PMID: 36790629 PMCID: PMC9828227 DOI: 10.1002/ajpa.24632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Revised: 06/29/2022] [Accepted: 09/13/2022] [Indexed: 11/07/2022]
Abstract
OBJECTIVES This study investigates patterns of bone functional adaptations in extant apes through comparing hindlimb to forelimb bone rigidity ratios in groups with varying levels of arboreality. MATERIALS AND METHODS Using CT scans, bone rigidity (J) was calculated at three regions of interest (ROI) along femoral and humeral diaphyses in Homo, Pongo, Pan, and Gorilla with further comparisons made between species and subspecies divisions within Pan and Gorilla. RESULTS Consistent with previous work on extant hominoids, species exhibited differences in midshaft femoral to humeral (F/H) rigidity ratios. Results of the present study confirm that these midshaft differences extend to 35% and 65% diaphyseal ROIs. Modern humans, exhibiting larger ratios, and orangutans, exhibiting smaller ratios, bracketed the intermediate African apes in comparisons. Within some African apes, limb rigidity ratios varied significantly between taxonomic groups. Eastern gorillas exhibited the highest mean ratios and chimpanzees the lowest at all three ROIs. In posthoc comparisons, chimpanzees and bonobos did not differ in relative limb rigidity ratios at any of the three ROIs. However, western gorillas were more similar to bonobos than eastern gorillas at 50% and 35% ROIs, but not at the 65% ROI. CONCLUSION Species, and to a lesser extent subspecies, can be distinguished by F/H limb rigidity ratios according to broad positional behavior patterns at multiple regions of interest along the diaphyses. Similarity of bonobos and western gorillas is in line with behavioral data of bonobos being the most terrestrial of Pan species, and western gorillas the most arboreal of the Gorilla groups.
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Affiliation(s)
- Lauren Sarringhaus
- Department of Evolutionary AnthropologyDuke UniversityDurhamNorth CarolinaUSA,Department of AnthropologyUniversity of MichiganAnn ArborMichiganUSA,Department of BiologyJames Madison UniversityHarrisonburgVirginiaUSA
| | - Kristi L. Lewton
- Department of Integrative Anatomical Sciences, Keck School of MedicineUniversity of Southern CaliforniaLos AngelesCaliforniaUSA
| | - Safiyyah Iqbal
- School of Animal, Plant and Environmental SciencesUniversity of the WitwatersrandJohannesburgSouth Africa
| | - Kristian J. Carlson
- Department of Integrative Anatomical Sciences, Keck School of MedicineUniversity of Southern CaliforniaLos AngelesCaliforniaUSA,Evolutionary Studies InstituteUniversity of the WitwatersrandJohannesburgSouth Africa
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7
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Ruff CB, Junno JA, Burgess ML, Canington SL, Harper C, Mudakikwa A, McFarlin SC. Body proportions and environmental adaptation in gorillas. AMERICAN JOURNAL OF BIOLOGICAL ANTHROPOLOGY 2022; 177:501-529. [PMID: 36787793 DOI: 10.1002/ajpa.24443] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 07/22/2021] [Accepted: 10/19/2021] [Indexed: 11/07/2022]
Abstract
OBJECTIVES Limb length and trunk proportions are determined in a large, taxonomically and environmentally diverse sample of gorillas and related to variation in locomotion, climate, altitude, and diet. MATERIALS AND METHODS The sample includes 299 gorilla skeletons, 115 of which are infants and juveniles, distributed between western lowland (G. gorilla gorilla), low and high elevation grauer (G. beringei graueri), and Virunga mountain gorillas (G. b. beringei). Limb bone and vertebral column lengths scaled to body mass are compared between subgroups by age group. RESULTS All G. beringei have relatively short 3rd metapodials and manual proximal phalanges compared to G. gorilla, and this difference is apparent in infancy. All G. beringei also have shortened total limb lengths relative to either body mass or vertebral column length, although patterns of variation in individual skeletal elements are more complex, and infants do not display the same patterns as adults. Mountain gorillas have relatively long clavicles, present in infancy, and a relatively long thoracic (but not lumbosacral) vertebral column. DISCUSSION A variety of environmental factors likely contributed to observed patterns of morphological variation among extant gorillas. We interpret the short hand and foot bones of all G. beringei as genetic adaptations to greater terrestriality in the last common ancestor of G. beringei; variation in other limb lengths to climatic adaptation, both genetic and developmental; and the larger thorax of G. b. beringei to adaptation to reduced oxygen pressure at high altitudes, again as a product of both genetic differences and environmental influences during development.
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Affiliation(s)
- Christopher B Ruff
- Center for Functional Anatomy and Evolution, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | | | - M Loring Burgess
- Peabody Museum of Archaeology and Ethnology, Harvard University, Cambridge, Massachusetts, USA
| | - Stephanie L Canington
- Center for Functional Anatomy and Evolution, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Christine Harper
- Department of Biomedical Sciences, Cooper Medical School of Rowan University, Camden, New Jersey, USA
| | - Antoine Mudakikwa
- Rwanda Development Board, Department of Tourism and Conservation, Kigali, Rwanda
| | - Shannon C McFarlin
- Department of Anthropology, Center for the Advanced Study of Human Paleobiology, The George Washington University, Washington, District of Columbia, USA.,Human Origins Program, Smithsonian's National Museum of Natural History, Washington, District of Columbia, USA
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8
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Deckers K, Tsegai ZJ, Skinner MM, Zeininger A, Kivell TL. Ontogenetic changes to metacarpal trabecular bone structure in mountain and western lowland gorillas. J Anat 2022; 241:82-100. [PMID: 35122239 PMCID: PMC9178373 DOI: 10.1111/joa.13630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 01/05/2022] [Accepted: 01/06/2022] [Indexed: 11/28/2022] Open
Abstract
The trabecular bone morphology of adult extant primates has been shown to reflect mechanical loading related to locomotion. However, ontogenetic studies of humans and other mammals suggest an adaptive lag between trabecular bone response and current mechanical loading patterns that could result in adult trabecular bone morphology reflecting juvenile behaviours. This study investigates ontogenetic changes in the trabecular bone structure of the third metacarpal of mountain gorillas (Gorilla beringei beringei; n = 26) and western lowland gorillas (Gorilla gorilla gorilla; n = 26) and its relationship to expected changes in locomotor loading patterns. Results show that trabecular bone reflects predicted mechanical loading throughout ontogeny. Bone volume fraction, trabecular thickness and trabecular number are low at birth and increase with age, although degree of anisotropy remains relatively stable throughout ontogeny. A high concentration of bone volume fraction can be observed in the distopalmar region of the third metacarpal epiphysis in early ontogeny, consistent with the high frequency of climbing, suspensory and other grasping behaviours in young gorillas. High trabecular bone concentration increases dorsally in the epiphysis during the juvenile period as terrestrial knuckle-walking becomes the primary form of locomotion. However, fusion of the epiphysis does not take place until 10-11 years of age, and overall trabecular structure does not fully reflect the adult pattern until 12 years of age, indicating a lag between adult-like behaviours and adult-like trabecular morphology. We found minimal differences in trabecular ontogeny between mountain and western lowland gorillas, despite presumed variation in the frequencies of arboreal locomotor behaviours. Altogether, ontogenetic changes in Gorilla metacarpal trabecular structure reflect overall genus-level changes in locomotor behaviours throughout development, but with some ontogenetic lag that should be considered when drawing functional conclusions from bone structure in extant or fossil adolescent specimens.
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Affiliation(s)
- Kim Deckers
- Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, Kent, UK
| | - Zewdi J Tsegai
- Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, Kent, UK.,Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Matthew M Skinner
- Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, Kent, UK.,Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Angel Zeininger
- Department of Evolutionary Anthropology, Duke University, Durham, North Carolina, USA
| | - Tracy L Kivell
- Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, Kent, UK.,Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
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9
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Arias-Martorell J, Zeininger A, Kivell TL. Trabecular structure of the elbow reveals divergence in knuckle-walking biomechanical strategies of African apes. Evolution 2021; 75:2959-2971. [PMID: 34570906 DOI: 10.1111/evo.14354] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 07/29/2021] [Accepted: 08/03/2021] [Indexed: 01/04/2023]
Abstract
African apes engage in a distinct form of locomotion called knuckle-walking, but there is much ambiguity as to when and how this locomotor behavior evolved. This study aims to elucidate potential differences in knuckle-walking elbow posture and loading in African apes through the study of trabecular bone. Using a whole-epiphysis approach, we quantified variation in the trabecular structure of the distal humerus of chimpanzees, western lowland gorillas, and mountain gorillas in comparison to orang-utans, siamangs, and a sample of Old and New World monkeys. Results demonstrate differences in the distribution of trabecular bone within the distal humerus that are consistent across taxa that habitually use a flexed-elbow posture in comparison to those that use an extended elbow during locomotion. Western lowland gorillas show an extended-elbow pattern consistent with the straight forelimb position during knuckle-walking, whereas chimpanzees show a flexed-elbow pattern. Unexpectedly, mountain gorillas show an intermediate pattern between their western counterparts and chimpanzees. The differences found in elbow joint posture between chimpanzees and gorillas, and between gorilla species, point to diversification in the knuckle-walking biomechanical strategies among African apes, which has implications in the debate regarding the locomotor behavior from which human bipedalism arose.
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Affiliation(s)
- Julia Arias-Martorell
- Institut Català de Paleontologia Miquel Crusafont, Edifici ICTA-ICP, Carrer Columnes s/n, Campus de la UAB, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain.,Animal Postcranial Evolution (APE) Laboratory, School of Anthropology and Conservation, Marlowe Building, University of Kent, Canterbury, UK
| | - Angel Zeininger
- Department of Evolutionary Anthropology, Duke University, Durham, North Carolina, USA
| | - Tracy L Kivell
- Animal Postcranial Evolution (APE) Laboratory, School of Anthropology and Conservation, Marlowe Building, University of Kent, Canterbury, UK.,Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
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10
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Harper CM, Ruff CB, Sylvester AD. Calcaneal shape variation in humans, nonhuman primates, and early hominins. J Hum Evol 2021; 159:103050. [PMID: 34438297 DOI: 10.1016/j.jhevol.2021.103050] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 06/29/2021] [Accepted: 06/29/2021] [Indexed: 01/08/2023]
Abstract
The foot has played a prominent role in evaluating early hominin locomotion. The calcaneus, in particular, plays an important role in weight-bearing. Although the calcanei of early hominins have been previously scrutinized, a three-dimensional analysis of the entire calcaneal shape has not been conducted. Here, we investigate the relationship between external calcaneal shape and locomotion in modern Homo sapiens (n = 130), Gorilla (n = 86), Pan (n = 112), Pongo (n = 31), Papio (n = 28), and hylobatids (Hylobates, Symphalangus; n = 32). We use these results to place the calcanei attributed to Australopithecus sediba, A. africanus, A. afarensis, H. naledi, and Homo habilis/Paranthropus boisei into a locomotor context. Calcanei were scanned using either surface scanning or micro-CT and their external shape analyzed using a three-dimensional geometric morphometric sliding semilandmark analysis. Blomberg's K statistic was used to estimate phylogenetic signal in the shape data. Shape variation was summarized using a principal components analysis. Procrustes distances between all taxa as well as distances between each fossil and the average of each taxon were calculated. Blomberg's K statistic was small (K = 0.1651), indicating weak phylogenetic effects, suggesting variation is driven by factors other than phylogeny (e.g., locomotion or body size). Modern humans have a large calcaneus relative to body size and display a uniquely convex cuboid facet, facilitating a rigid midfoot for bipedalism. More arboreal great apes display relatively deeper cuboid facet pivot regions for increased midfoot mobility. Australopithecus afarensis demonstrates the most human-like calcaneus, consistent with obligate bipedalism. Homo naledi is primarily modern human-like, but with some intermediate traits, suggesting a different form of bipedalism than modern humans. Australopithecus africanus, A. sediba, and H. habilis/P. boisei calcanei all possess unique combinations of human and nonhuman ape-like morphologies, suggesting a combination of bipedal and arboreal behaviors.
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Affiliation(s)
- Christine M Harper
- The Johns Hopkins University School of Medicine, Center for Functional Anatomy and Evolution, 1830 East Monument Street, Room 302, Baltimore, MD 21205, United States; Cooper Medical School of Rowan University, Department of Biomedical Sciences, 401 S Broadway, Room 453, Camden, NJ 08103, United States.
| | - Christopher B Ruff
- The Johns Hopkins University School of Medicine, Center for Functional Anatomy and Evolution, 1830 East Monument Street, Room 302, Baltimore, MD 21205, United States
| | - Adam D Sylvester
- The Johns Hopkins University School of Medicine, Center for Functional Anatomy and Evolution, 1830 East Monument Street, Room 302, Baltimore, MD 21205, United States
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11
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Zelazny KG, Sylvester AD, Ruff CB. Bilateral asymmetry and developmental plasticity of the humerus in modern humans. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2021; 174:418-433. [PMID: 33460465 DOI: 10.1002/ajpa.24213] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 11/08/2020] [Accepted: 12/08/2020] [Indexed: 11/12/2022]
Abstract
OBJECTIVE This study investigates bilateral asymmetry in the humerus of modern human populations with differing activity patterns to assess the relative plasticity of different bone regions in response to environmental influences, particularly the biomechanical demands of handedness. METHODS External breadths, cross-sectional properties, and centroid sizes were used to quantify directional and absolute asymmetry of humeral diaphyseal, distal periarticular, and articular regions in six populations with differing subsistence strategies (total n = 244). Geometric section properties were measured using computed tomography at six locations along the distal humerus, while centroid sizes of the distal articular and periarticular regions, as well as eight segments of the diaphysis, were extracted from external landmark data. Bilateral asymmetries were compared between populations and sexes. Each property was also tested for correlation with bilateral asymmetry at 40% of bone length, which has been shown to correlate with handedness. RESULTS Asymmetry is highest in the diaphysis, but significant through all distal bone regions. Asymmetry increases in the region of the deltoid tuberosity, and progressively declines distally through the shaft and distal periarticular region. Articular asymmetry is higher than periarticular asymmetry, approaching levels seen just proximal to the olecranon fossa, and is weakly but significantly correlated with diaphyseal asymmetry. Hunter-gatherers from Indian Knoll have significantly higher levels of asymmetry than other groups and are more sexually dimorphic, particularly in cross-sectional properties of the diaphysis. CONCLUSIONS Humeral dimensions throughout the diaphysis, including regions currently used in taxonomic assignments of fossil hominins, likely respond to in vivo use, including population and sex-specific behaviors.
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Affiliation(s)
- Kaya G Zelazny
- Center for Functional Anatomy and Evolution, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Adam D Sylvester
- Center for Functional Anatomy and Evolution, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Christopher B Ruff
- Center for Functional Anatomy and Evolution, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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12
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Nadell JA, Elton S, Kovarovic K. Ontogenetic and morphological variation in primate long bones reflects signals of size and behavior. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2020; 174:327-351. [PMID: 33368154 DOI: 10.1002/ajpa.24198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 11/08/2020] [Accepted: 11/19/2020] [Indexed: 11/05/2022]
Abstract
OBJECTIVES Many primates change their locomotor behavior as they mature from infancy to adulthood. Here we investigate how long bone cross-sectional geometry in Pan, Gorilla, Pongo, Hylobatidae, and Macaca varies in shape and form over ontogeny, including whether specific diaphyseal cross sections exhibit signals of periosteal adaptation or canalization. MATERIALS AND METHODS Diaphyseal cross sections were analyzed in an ontogenetic series across infant, juvenile, and adult subgroups. Three-dimensional laser-scanned long bone models were sectioned at midshaft (50% of biomechanical length) and distally (20%) along the humerus and femur. Traditional axis ratios acted as indices of cross-sectional circularity, while geometric morphometric techniques were used to study cross-sectional allometry and ontogenetic trajectory. RESULTS The humeral midshaft is a strong indicator of posture and locomotor profile in the sample across development, while the mid-femur appears more reflective of shifts in size. By comparison, the distal diaphyses of both limb elements are more ontogenetically constrained, where periosteal shape is largely static across development relative to size, irrespective of a given taxon's behavior or ecology. DISCUSSION Primate limb shape is not only highly variable between taxa over development, but at discrete humeral and femoral diaphyseal locations. Overall, periosteal shape of the humeral and femoral midshaft cross sections closely reflects ontogenetic transitions in behavior and size, respectively, while distal shape in both bones appears more genetically constrained across intraspecific development, regardless of posture or size. These findings support prior research on tradeoffs between function and safety along the limbs.
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Affiliation(s)
- Jason A Nadell
- Department of Anthropology, Durham University, Durham, United Kingdom
| | - Sarah Elton
- Department of Anthropology, Durham University, Durham, United Kingdom
| | - Kris Kovarovic
- Department of Anthropology, Durham University, Durham, United Kingdom
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Ruff CB, Junno JA, Eckardt W, Gilardi K, Mudakikwa A, McFarlin SC. Skeletal ageing in Virunga mountain gorillas. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190606. [PMID: 32951549 DOI: 10.1098/rstb.2019.0606] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Bone loss and heightened fracture risk are common conditions associated with ageing in modern human populations and have been attributed to both hormonal and other metabolic and behavioural changes. To what extent these age-related trends are specific to modern humans or generally characteristic of natural populations of other taxa is not clear. In this study, we use computed tomography to examine age changes in long bone and vertebral structural properties of 34 wild-adult Virunga mountain gorillas (Gorilla beringei beringei) whose skeletons were recovered from natural accumulations. Chronological ages were known or estimated from sample-specific dental wear formulae and ranged between 11 and 43 years. Gorillas show some of the same characteristics of skeletal ageing as modern humans, including endosteal and some periosteal expansion. However, unlike in humans, there is no decline in cortical or trabecular bone density, or in combined geometric-density measures of strength, nor do females show accelerated bone loss later in life. We attribute these differences to the lack of an extended post-reproductive period in gorillas, which provides protection against bone resorption. Increases in age-related fractures (osteoporosis) in modern humans may be a combined effect of an extended lifespan and lower activity levels earlier in life. This article is part of the theme issue 'Evolution of the primate ageing process'.
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Affiliation(s)
- Christopher B Ruff
- Center for Functional Anatomy and Evolution, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | | | | | - Kirsten Gilardi
- Mountain Gorilla Veterinary Project, University of California at Davis, Davis, California, USA
| | - Antoine Mudakikwa
- Department of Tourism and Conservation, Rwanda Development Board, Kigali, Rwanda
| | - Shannon C McFarlin
- Department of Anthropology, Center for the Advanced Study of Human Paleobiology, The George Washington University, Washington, DC, USA
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Harper CM, Ruff CB, Sylvester AD. Gorilla calcaneal morphological variation and ecological divergence. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2020; 174:49-65. [PMID: 32871028 DOI: 10.1002/ajpa.24135] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 06/11/2020] [Accepted: 08/02/2020] [Indexed: 01/19/2023]
Abstract
OBJECTIVES The primate foot has been extensively investigated because of its role in weight-bearing; however, the calcaneus has been relatively understudied. Here we examine entire gorilla calcaneal external shape to understand its relationship with locomotor behavior. MATERIALS AND METHODS Calcanei of Gorilla gorilla gorilla (n = 43), Gorilla beringei graueri (n = 20), and Gorilla beringei beringei (n = 15) were surface or micro-CT scanned. External shape was analyzed through a three-dimensional geometric morphometric sliding semilandmark analysis. Semilandmarks were slid relative to an updated Procrustes average in order to minimize the bending energy of the thin plate spline interpolation function. Shape variation was summarized using principal components analysis of shape coordinates. Procrustes distances between taxa averages were calculated and resampling statistics run to test pairwise differences. Linear measures were collected and regressed against estimated body mass. RESULTS All three taxa exhibit statistically different morphologies (p < .001 for pairwise comparisons). G. g. gorilla demonstrates an anteroposteriorly elongated calcaneus with a deeper cuboid pivot region and mediolaterally flatter posterior talar facet. G. b. beringei possesses the flattest cuboid and most medially-angled posterior talar facets. G. b. graueri demonstrates intermediate articular facet morphology, a medially-angled tuberosity, and an elongated peroneal trochlea. DISCUSSION Articular facet differences separate gorillas along a locomotor gradient. G. g. gorilla is adapted for arboreality with greater joint mobility, while G. b. beringei is adapted for more stereotypical loads associated with terrestriality. G. b. graueri's unique posterolateral morphology may be due to a secondary transition to greater arboreality from a more terrestrial ancestor.
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Affiliation(s)
- Christine M Harper
- Center for Functional Anatomy and Evolution, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Christopher B Ruff
- Center for Functional Anatomy and Evolution, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Adam D Sylvester
- Center for Functional Anatomy and Evolution, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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Fatica LM, Almécija S, McFarlin SC, Hammond AS. Pelvic shape variation among gorilla subspecies: Phylogenetic and ecological signals. J Hum Evol 2019; 137:102684. [DOI: 10.1016/j.jhevol.2019.102684] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 09/23/2019] [Accepted: 09/24/2019] [Indexed: 01/28/2023]
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Ruff CB, Harper CM, Goldstein DM, Daegling DJ, McGraw WS. Long bone structural proportions and locomotor behavior in Cercopithecidae. J Hum Evol 2019; 132:47-60. [DOI: 10.1016/j.jhevol.2019.04.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 04/11/2019] [Accepted: 04/12/2019] [Indexed: 02/06/2023]
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Marchi D, Harper C, Chirchir H, Ruff C. Relative fibular strength and locomotor behavior in KNM-WT 15000 and OH 35. J Hum Evol 2019; 131:48-60. [DOI: 10.1016/j.jhevol.2019.02.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 02/01/2019] [Accepted: 02/21/2019] [Indexed: 12/14/2022]
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18
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Galbany J, Muhire T, Vecellio V, Mudakikwa A, Nyiramana A, Cranfield MR, Stoinski TS, McFarlin SC. Incisor tooth wear and age determination in mountain gorillas from Volcanoes National Park, Rwanda. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2018; 167:930-935. [PMID: 30368801 DOI: 10.1002/ajpa.23720] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Revised: 09/05/2018] [Accepted: 09/11/2018] [Indexed: 11/10/2022]
Abstract
OBJECTIVES Ecological factors, but also tooth-to-tooth contact over time, have a dramatic effect on tooth wear in primates. The aim of this study is to test whether incisor tooth wear changes predictably with age and can thus be used as an age estimation method in a wild population of mountain gorillas (Gorilla beringei beringei) from Volcanoes National Park, Rwanda. MATERIALS AND METHODS In mountain gorillas of confidently known chronological age (N = 24), we measured the crown height of all permanent maxillary and mandibular incisors (I1 , I1 , I2 , I2 ) as a proxy for incisal macrowear. Linear and quadratic regressions for each incisor were used to test whether age can be predicted by crown height. Using these models, we then predicted age at death of two individual mountain gorillas of probable identifications, based on their incisor crown height. RESULTS Age decreased significantly with incisor height for all teeth, but the upper first incisors (I1 ) provided the best results, with the lowest Akaike's Information Criterion corrected for small sample size (AICc) and lowest Standard Error of the Estimate (SEE). When the best age equations for each sex were applied to gorillas with probable identifications, the predicted ages differed 1.58 and 3.33 years from the probable ages of these individuals. CONCLUSIONS Our findings corroborate that incisor crown height, a proxy for incisal wear, varies predictably with age. This relationship can be used to estimate age at death of unknown gorillas in the skeletal collection, and in some cases, to corroborate the identity of individual gorillas recovered from the forest postmortem at an advanced state of decomposition. Such identifications help fill gaps in the demographic database and support research that requires individual-level data.
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Affiliation(s)
- Jordi Galbany
- Department of Anthropology, Center for the Advanced Study of Human Paleobiology, The George Washington University, Washington, District of Columbia.,Department of Social Psychology and Quantitative Psychology, University of Barcelona, Barcelona, Spain
| | - Thadée Muhire
- Dian Fossey Gorilla Fund International, Atlanta, Georgia
| | | | - Antoine Mudakikwa
- Department of Tourism and Conservation, Rwanda Development Board, Kigali, Rwanda
| | | | - Michael R Cranfield
- Mountain Gorilla Veterinary Project, University of California at Davis, Davis, California
| | | | - Shannon C McFarlin
- Department of Anthropology, Center for the Advanced Study of Human Paleobiology, The George Washington University, Washington, District of Columbia
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Canington SL, Sylvester AD, Burgess ML, Junno J, Ruff CB. Long bone diaphyseal shape follows different ontogenetic trajectories in captive and wild gorillas. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2018; 167:366-376. [DOI: 10.1002/ajpa.23636] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Revised: 05/31/2018] [Accepted: 06/01/2018] [Indexed: 02/01/2023]
Affiliation(s)
- Stephanie L. Canington
- Center for Functional Anatomy and Evolution Johns Hopkins University School of Medicine Baltimore Maryland
| | - Adam D. Sylvester
- Center for Functional Anatomy and Evolution Johns Hopkins University School of Medicine Baltimore Maryland
| | - M. Loring Burgess
- Center for Functional Anatomy and Evolution Johns Hopkins University School of Medicine Baltimore Maryland
| | | | - Christopher B. Ruff
- Center for Functional Anatomy and Evolution Johns Hopkins University School of Medicine Baltimore Maryland
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