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Spear JK, Grabowski M, Sekhavati Y, Costa CE, Goldstein DM, Petrullo LA, Peterson AL, Lee AB, Shattuck MR, Gómez-Olivencia A, Williams SA. Evolution of vertebral numbers in primates, with a focus on hominoids and the last common ancestor of hominins and panins. J Hum Evol 2023; 179:103359. [PMID: 37099927 DOI: 10.1016/j.jhevol.2023.103359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 03/14/2023] [Accepted: 03/14/2023] [Indexed: 04/28/2023]
Abstract
The primate vertebral column has been extensively studied, with a particular focus on hominoid primates and the last common ancestor of humans and chimpanzees. The number of vertebrae in hominoids-up to and including the last common ancestor of humans and chimpanzees-is subject to considerable debate. However, few formal ancestral state reconstructions exist, and none include a broad sample of primates or account for the correlated evolution of the vertebral column. Here, we conduct an ancestral state reconstruction using a model of evolution that accounts for both homeotic (changes of one type of vertebra to another) and meristic (addition or loss of a vertebra) changes. Our results suggest that ancestral primates were characterized by 29 precaudal vertebrae, with the most common formula being seven cervical, 13 thoracic, six lumbar, and three sacral vertebrae. Extant hominoids evolved tail loss and a reduced lumbar column via sacralization (homeotic transition at the last lumbar vertebra). Our results also indicate that the ancestral hylobatid had seven cervical, 13 thoracic, five lumbar, and four sacral vertebrae, and the ancestral hominid had seven cervical, 13 thoracic, four lumbar, and five sacral vertebrae. The last common ancestor of humans and chimpanzees likely either retained this ancestral hominid formula or was characterized by an additional sacral vertebra, possibly acquired through a homeotic shift at the sacrococcygeal border. Our results support the 'short-back' model of hominin vertebral evolution, which postulates that hominins evolved from an ancestor with an African ape-like numerical composition of the vertebral column.
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Affiliation(s)
- Jeffrey K Spear
- Center for the Study of Human Origins, Department of Anthropology, New York University, New York, NY, USA; New York Consortium in Evolutionary Primatology, New York, NY, USA.
| | - Mark Grabowski
- Research Centre in Evolutionary Anthropology and Paleoecology, Liverpool John Moores University, Liverpool, UK; Department of Biosciences, Centre for Ecological and Evolutionary Synthesis, University of Oslo, Oslo, Norway
| | - Yeganeh Sekhavati
- Department of Anthropology, Washington University in St. Louis, St. Louis, MO, USA
| | - Christina E Costa
- Center for the Study of Human Origins, Department of Anthropology, New York University, New York, NY, USA; New York Consortium in Evolutionary Primatology, New York, NY, USA
| | - Deanna M Goldstein
- Department of Anatomical Sciences, Renaissance School of Medicine, Stony Brook University, Stony Brook, NY, USA
| | - Lauren A Petrullo
- Department of Psychology, University of Michigan, Ann Arbor, MI, USA
| | - Amy L Peterson
- Smithsonian Institution, National Museum of Natural History, Washington DC, USA
| | - Amanda B Lee
- Data Scientist, Jellyfish, Suite 3033, 220 N Green St, Chicago, IL, USA
| | | | - Asier Gómez-Olivencia
- Departamento de Geología, Facultad de Ciencia y Tecnología, Universidad Del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), Barrio Sarriena S/n, 48940 Bilbao, Spain; Sociedad de Ciencias Aranzadi, Zorroagagaina 11, 20014 Donostia-San Sebastián, Spain; Centro UCM-ISCIII de Investigación Sobre Evolución y Comportamiento Humanos, Avda. Monforte de Lemos 5 (Pabellón 14), 28029 Madrid, Spain
| | - Scott A Williams
- Center for the Study of Human Origins, Department of Anthropology, New York University, New York, NY, USA; New York Consortium in Evolutionary Primatology, New York, NY, USA
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2
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Mongle CS, Strait DS, Grine FE. An updated analysis of hominin phylogeny with an emphasis on re-evaluating the phylogenetic relationships of Australopithecus sediba. J Hum Evol 2023; 175:103311. [PMID: 36706599 DOI: 10.1016/j.jhevol.2022.103311] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 12/16/2022] [Accepted: 12/16/2022] [Indexed: 01/26/2023]
Abstract
The discovery and description of Australopithecus sediba has reignited the debate over the evolutionary history of the australopiths and the genus Homo. It has been suggested that A. sediba may be an ancestor of Homo because it possesses a mosaic of derived Homo-like and primitive australopith-like traits. However, an alternative hypothesis proposes that the majority of the purported Homo-like craniodental characters can be attributed to the juvenile status of the type specimen, MH1. We conducted an independent character assessment of the craniodental morphology of A. sediba, with particular emphasis on evaluating whether the ontogenetic status of MH1 may have affected its purported Homo-like characteristics. In doing so, we have also expanded fossil hypodigms to incorporate the new Australopithecus anamensis cranium from Woranso-Mille (MRD-VP-1/1), as well as recently described Paranthropus robustus cranial remains from Drimolen (DNH 7, DNH 155). Morphological character data were analyzed using both standard parsimony and Bayesian techniques. In addition, we conducted a series of Bayesian analyses constrained to evaluate the hypothesis that Australopithecus africanus and A. sediba are sister taxa. Based on the results of the parsimony and Bayesian analyses, we could not reject the hypothesis that A. sediba shares its closest phylogenetic affinities with the genus Homo. Therefore, based on currently available craniodental evidence, we conclude that A. sediba is plausibly the terminal end of a lineage that shared a common ancestor with the earliest representatives of Homo. We caution, however, that the discovery of new A. sediba fossils preserving adult cranial morphology or the inclusion of postcranial characters may ultimately necessitate a re-evaluation of this hypothesis.
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Affiliation(s)
- Carrie S Mongle
- Department of Anthropology, Stony Brook University, Stony Brook, NY 11794-4364, USA; Division of Anthropology, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024-5192, USA; Turkana Basin Institute, Stony Brook University, Stony Brook, NY 11794-4364, USA.
| | - David S Strait
- Department of Anthropology, Washington University in St. Louis, 1 Brookings Dr, St. Louis, MO 63130, USA; Palaeo-Research Institute, University of Johannesburg, Cottesloe, Johannesburg, 2092, South Africa
| | - Frederick E Grine
- Department of Anthropology, Stony Brook University, Stony Brook, NY 11794-4364, USA; Department of Anatomical Sciences, Stony Brook University, Stony Brook, NY 11794-4364, USA
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Cazenave M, Kivell TL. Challenges and perspectives on functional interpretations of australopith postcrania and the reconstruction of hominin locomotion. J Hum Evol 2023; 175:103304. [PMID: 36563461 DOI: 10.1016/j.jhevol.2022.103304] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 11/15/2022] [Accepted: 11/16/2022] [Indexed: 12/24/2022]
Abstract
In 1994, Hunt published the 'postural feeding hypothesis'-a seminal paper on the origins of hominin bipedalism-founded on the detailed study of chimpanzee positional behavior and the functional inferences derived from the upper and lower limb morphology of the Australopithecus afarensis A.L. 288-1 partial skeleton. Hunt proposed a model for understanding the potential selective pressures on hominins, made robust, testable predictions based on Au. afarensis functional morphology, and presented a hypothesis that aimed to explain the dual functional signals of the Au. afarensis and, more generally, early hominin postcranium. Here we synthesize what we have learned about Au. afarensis functional morphology and the dual functional signals of two new australopith discoveries with relatively complete skeletons (Australopithecus sediba and StW 573 'Australopithecus prometheus'). We follow this with a discussion of three research approaches that have been developed for the purpose of drawing behavioral inferences in early hominins: (1) developments in the study of extant apes as models for understanding hominin origins; (2) novel and continued developments to quantify bipedal gait and locomotor economy in extant primates to infer the locomotor costs from the anatomy of fossil taxa; and (3) novel developments in the study of internal bone structure to extract functional signals from fossil remains. In conclusion of this review, we discuss some of the inherent challenges of the approaches and methodologies adopted to reconstruct the locomotor modes and behavioral repertoires in extinct primate taxa, and notably the assessment of habitual terrestrial bipedalism in early hominins.
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Affiliation(s)
- Marine Cazenave
- Division of Anthropology, American Museum of Natural History, New York, USA; Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, UK; Department of Anatomy, Faculty of Health Sciences, University of Pretoria, South Africa.
| | - Tracy L Kivell
- Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury, UK; Centre for the Exploration of the Deep Human Journey, University of the Witwatersrand, Johannesburg, South Africa
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Grine FE, Mongle CS, Fleagle JG, Hammond AS. The taxonomic attribution of African hominin postcrania from the Miocene through the Pleistocene: Associations and assumptions. J Hum Evol 2022; 173:103255. [PMID: 36375243 DOI: 10.1016/j.jhevol.2022.103255] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 08/21/2022] [Accepted: 08/22/2022] [Indexed: 11/06/2022]
Abstract
Postcranial bones may provide valuable information about fossil taxa relating to their locomotor habits, manipulative abilities and body sizes. Distinctive features of the postcranial skeleton are sometimes noted in species diagnoses. Although numerous isolated postcranial fossils have become accepted by many workers as belonging to a particular species, it is worthwhile revisiting the evidence for each attribution before including them in comparative samples in relation to the descriptions of new fossils, functional analyses in relation to particular taxa, or in evolutionary contexts. Although some workers eschew the taxonomic attribution of postcranial fossils as being less important (or interesting) than interpreting their functional morphology, it is impossible to consider the evolution of functional anatomy in a taxonomic and phylogenetic vacuum. There are 21 widely recognized hominin taxa that have been described from sites in Africa dated from the Late Miocene to the Middle Pleistocene; postcranial elements have been attributed to 17 of these. The bones that have been thus assigned range from many parts of a skeleton to isolated elements. However, the extent to which postcranial material can be reliably attributed to a specific taxon varies considerably from site to site and species to species, and is often the subject of considerable debate. Here, we review the postcranial remains attributed to African hominin taxa from the Late Miocene to the Middle and Late Pleistocene and place these assignations into categories of reliability. The catalog of attributions presented here may serve as a guide for making taxonomic decisions in the future.
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Affiliation(s)
- Frederick E Grine
- Department of Anthropology, Stony Brook University, Stony Brook, NY 11794-4364, USA; Department of Anatomical Sciences, Stony Brook University, Stony Brook, NY 11794-4364, USA.
| | - Carrie S Mongle
- Department of Anthropology, Stony Brook University, Stony Brook, NY 11794-4364, USA; Division of Anthropology, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024-5192, USA; Turkana Basin Institute, Stony Brook University, Stony Brook, NY 11794-4364, USA
| | - John G Fleagle
- Department of Anatomical Sciences, Stony Brook University, Stony Brook, NY 11794-4364, USA
| | - Ashley S Hammond
- Division of Anthropology, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024-5192, USA; New York Consortium of Evolutionary Primatology (NYCEP), New York, NY 10024, USA
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5
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Jung H, von Cramon-Taubadel N. Morphological modularity in the anthropoid axial skeleton. J Hum Evol 2022; 172:103256. [PMID: 36156434 DOI: 10.1016/j.jhevol.2022.103256] [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: 12/16/2021] [Revised: 08/19/2022] [Accepted: 08/22/2022] [Indexed: 01/31/2023]
Abstract
Previous research has found that hominoids have stronger modularity between limb elements than other anthropoids, suggesting that there is less constraint on morphological diversification (e.g., limb proportions) in hominoids in terms of evolutionary independence. However, degrees of modularity in the axial skeleton have not been investigated across a broad range of anthropoid taxa. Thus, it is unknown whether hominoids also have stronger modularity in the axial skeleton than other anthropoids, which has implications for the evolution of diverse torso morphologies in Miocene apes as well as the evolution of novel characteristics in the skull and vertebrae of fossil hominins. In this study, 12 anthropoid genera were sampled to examine degrees of modularity between axial skeletal elements (i.e., cranium, mandible, vertebrae, and sacrum). Covariance ratio coefficients were calculated using variance/covariance matrices of interlandmark distances for each axial skeletal element to evaluate degrees of modularity. The results showed that Alouatta, Hylobates, Gorilla, Pan, and Homo showed generally stronger modularity than other anthropoid taxa when considering all axial skeletal elements. When only considering the vertebral elements (i.e., vertebrae and sacrum), Alouatta, Hylobates, Gorilla, and Pan showed generally stronger modularity than other anthropoid taxa. Humans showed stronger modularity between the skull and vertebrae than other hominoids. Thus, the evolution of novel characteristics in the skull and vertebral column may have been less constrained in fossil hominins due to the dissociation of trait covariation between axial skeletal elements in hominoid ancestors, thus fostering more evolutionary independence between the skull and vertebral column.
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Affiliation(s)
- Hyunwoo Jung
- Buffalo Human Evolutionary Morphology Lab, Department of Anthropology, University at Buffalo, SUNY, 380 Academic Center, Ellicott Complex, Buffalo, NY 14261, USA; Department of Anatomy, College of Graduate Studies, Midwestern University, 19555 N 59th Ave, Glendale, AZ 85308, USA.
| | - Noreen von Cramon-Taubadel
- Buffalo Human Evolutionary Morphology Lab, Department of Anthropology, University at Buffalo, SUNY, 380 Academic Center, Ellicott Complex, Buffalo, NY 14261, USA
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6
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Murray AA. Variability and the form-function framework in evolutionary biomechanics and human locomotion. EVOLUTIONARY HUMAN SCIENCES 2022; 4:e29. [PMID: 37588899 PMCID: PMC10426129 DOI: 10.1017/ehs.2022.28] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The form-function conceptual framework, which assumes a strong relationship between the structure of a particular trait and its function, has been crucial for understanding morphological variation and locomotion among extant and fossil species across many disciplines. In biological anthropology, it is the lens through which many important questions and hypotheses have been tackled with respect to relationships between morphology and locomotor kinematics, energetics and performance. However, it is becoming increasingly evident that the morphologies of fossil hominins, apes and humans can confer considerable locomotor diversity and flexibility, and can do so with a range of kinematics depending on soft tissue plasticity and environmental and cultural factors. This complexity is not built into traditional biomechanical or mathematical models of relationships between structure and kinematics or energetics, limiting our interpretation of what bone structure is telling us about behaviour in the past. The nine papers presented in this Special Collection together address some of the challenges that variation in the relationship between form and function pose in evolutionary biomechanics, to better characterise the complexity linking structure and function and to provide tools through which we may begin to incorporate some of this complexity into our functional interpretations.
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Affiliation(s)
- Alison A. Murray
- Department of Anthropology, University of Victoria, Cornett Building Room B228, 3800 Finnerty Road, Victoria, BC, CanadaV8P 5C2
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7
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Williams SA, Zeng I, Paton GJ, Yelverton C, Dunham C, Ostrofsky KR, Shukman S, Avilez MV, Eyre J, Loewen T, Prang TC, Meyer MR. Inferring lumbar lordosis in Neandertals and other hominins. PNAS NEXUS 2022; 1:pgab005. [PMID: 36712807 PMCID: PMC9801964 DOI: 10.1093/pnasnexus/pgab005] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 11/24/2021] [Accepted: 12/19/2021] [Indexed: 02/07/2023]
Abstract
Lumbar lordosis is a key adaptation to bipedal locomotion in the human lineage. Dorsoventral spinal curvatures enable the body's center of mass to be positioned above the hip, knee, and ankle joints, and minimize the muscular effort required for postural control and locomotion. Previous studies have suggested that Neandertals had less lordotic (ventrally convex) lumbar columns than modern humans, which contributed to historical perceptions of postural and locomotor differences between the two groups. Quantifying lower back curvature in extinct hominins is entirely reliant upon bony correlates of overall lordosis, since the latter is significantly influenced by soft tissue structures (e.g. intervertebral discs). Here, we investigate sexual dimorphism, ancestry, and lifestyle effects on lumbar vertebral body wedging and inferior articular facet angulation, two features previously shown to be significantly correlated with overall lordosis in living individuals, in a large sample of modern humans and Neandertals. Our results demonstrate significant differences between postindustrial cadaveric remains and archaeological samples of people that lived preindustrial lifestyles. We suggest these differences are related to activity and other aspects of lifestyle rather than innate population (ancestry) differences. Neandertal bony correlates of lumbar lordosis are significantly different from all human samples except preindustrial males. Therefore, although Neandertals demonstrate more bony kyphotic wedging than most modern humans, we cast doubt on proposed locomotor and postural differences between the two lineages based on inferred lumbar lordosis (or lack thereof), and we recommend future research compare fossils to modern humans from varied populations and not just recent, postindustrial samples.
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Affiliation(s)
- Scott A Williams
- To whom correspondence should be addressed: 25 Waverly Place, New York, NY 10003, USA. Ph: 212-s992-9583. E-mail:
| | - Iris Zeng
- Department of Architecture, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Glen J Paton
- Department of Chiropractic, Faculty of Health Sciences, University of Johannesburg, 2094, Johannesburg, South Africa
| | - Christopher Yelverton
- Evolutionary Studies Institute, University of the Witwatersrand, Private Bag 3, Wits 2050, Johannesburg, South Africa,Department of Chiropractic, Faculty of Health Sciences, University of Johannesburg, 2094, Johannesburg, South Africa
| | - ChristiAna Dunham
- Center for the Study of Human Origins, Department of Anthropology, New York University, New York, NY 10003, USA,Department of Anthropology, Texas State University, San Marcos, TX 78666, USA
| | - Kelly R Ostrofsky
- Department of Anatomy, College of Osteopathic Medicine, New York Institute of Technology, Old Westbury, NY 11569, USA
| | - Saul Shukman
- Center for the Study of Human Origins, Department of Anthropology, New York University, New York, NY 10003, USA
| | - Monica V Avilez
- Center for the Study of Human Origins, Department of Anthropology, New York University, New York, NY 10003, USA,New York Consortium in Evolutionary Primatology, New York, NY 10024, USA
| | - Jennifer Eyre
- Center for the Study of Human Origins, Department of Anthropology, New York University, New York, NY 10003, USA,Department of Anthropology, Bryn Mawr College, Bryn Mawr, PA 19010, USA
| | - Tisa Loewen
- School of Human Evolution and Social Change, Arizona State University, Tempe, AZ 85287, USA
| | - Thomas C Prang
- Department of Anthropology, Texas A&M University, College Station, TX 77843, USA
| | - Marc R Meyer
- Department of Anthropology, Chaffey College, Rancho Cucamonga, CA 91737, USA
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