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Nalley TK, Scott JE, McGechie F, Grider-Potter N. Comparative ontogeny of functional aspects of human cervical vertebrae. AMERICAN JOURNAL OF BIOLOGICAL ANTHROPOLOGY 2024; 183:e24788. [PMID: 37283367 DOI: 10.1002/ajpa.24788] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 05/15/2023] [Accepted: 05/24/2023] [Indexed: 06/08/2023]
Abstract
OBJECTIVES Differences between adult humans and great apes in cervical vertebral morphology are well documented, but the ontogeny of this variation is still largely unexplored. This study examines patterns of growth in functionally relevant features of C1, C2, C4, and C6 in extant humans and apes to understand the development of their disparate morphologies. MATERIALS AND METHODS Linear and angular measurements were taken from 530 cervical vertebrae representing 146 individual humans, chimpanzees, gorillas, and orangutans. Specimens were divided into three age-categories based on dental eruption: juvenile, adolescent, and adult. Inter- and intraspecific comparisons were evaluated using resampling methods. RESULTS Of the eighteen variables examined here, seven distinguish humans from apes at the adult stage. Human-ape differences in features related to atlantoaxial joint function tend to be established by the juvenile stage, whereas differences in features related to the nuchal musculature and movement of the subaxial elements do not fully emerge until adolescence or later. The orientation of the odontoid process-often cited as a feature that distinguishes humans from apes-is similar in adult humans and adult chimpanzees, but the developmental patterns are distinct, with human adultlike morphology being achieved much earlier. DISCUSSION The biomechanical consequences of the variation observed here is poorly understood. Whether the differences in growth patterns represent functional links to cranial development or postural changes, or both, requires additional investigation. Determining when humanlike ontogenetic patterns evolved in hominins may provide insight into the functional basis driving the morphological divergence between extant humans and apes.
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Affiliation(s)
- Thierra K Nalley
- Medical Anatomical Sciences Department, College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona, California, USA
| | - Jeremiah E Scott
- Medical Anatomical Sciences Department, College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona, California, USA
| | - Faye McGechie
- Department of Basic Medical Sciences, University of Arizona College of Medicine-Phoenix, Phoenix, Arizona, USA
| | - Neysa Grider-Potter
- Department of Cell Systems and Anatomy, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
- Southwest National Primate Research Center, Texas Biomedical Research Institute, San Antonio, Texas, USA
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Beaudet A, Clarke RJ, Heaton JL, Pickering TR, Carlson KJ, Crompton RH, Jashashvili T, Bruxelles L, Jakata K, Bam L, Van Hoorebeke L, Kuman K, Stratford D. The atlas of StW 573 and the late emergence of human-like head mobility and brain metabolism. Sci Rep 2020; 10:4285. [PMID: 32179760 PMCID: PMC7075956 DOI: 10.1038/s41598-020-60837-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 02/18/2020] [Indexed: 12/24/2022] Open
Abstract
Functional morphology of the atlas reflects multiple aspects of an organism’s biology. More specifically, its shape indicates patterns of head mobility, while the size of its vascular foramina reflects blood flow to the brain. Anatomy and function of the early hominin atlas, and thus, its evolutionary history, are poorly documented because of a paucity of fossilized material. Meticulous excavation, cleaning and high-resolution micro-CT scanning of the StW 573 (‘Little Foot’) skull has revealed the most complete early hominin atlas yet found, having been cemented by breccia in its displaced and flipped over position on the cranial base anterolateral to the foramen magnum. Description and landmark-free morphometric analyses of the StW 573 atlas, along with other less complete hominin atlases from Sterkfontein (StW 679) and Hadar (AL 333-83), confirm the presence of an arboreal component in the positional repertoire of Australopithecus. Finally, assessment of the cross-sectional areas of the transverse foramina of the atlas and the left carotid canal in StW 573 further suggests there may have been lower metabolic costs for cerebral tissues in this hominin than have been attributed to extant humans and may support the idea that blood perfusion of these tissues increased over the course of hominin evolution.
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Affiliation(s)
- Amélie Beaudet
- School of Geography, Archaeology and Environmental Studies, University of the Witwatersrand, Private Bag 3, Johannesburg, WITS, 2050, South Africa. .,Department of Anatomy, University of Pretoria, PO Box 2034, Pretoria, 0001, South Africa.
| | - Ronald J Clarke
- Evolutionary Studies Institute, University of the Witwatersrand, Private Bag 3, Johannesburg, WITS, 2050, South Africa
| | - Jason L Heaton
- Evolutionary Studies Institute, University of the Witwatersrand, Private Bag 3, Johannesburg, WITS, 2050, South Africa.,Department of Biology, Birmingham-Southern College, 900 Arkadelphia Road, Birmingham, AL, 35254, United States.,Plio-Pleistocene Palaeontology Section, Department of Vertebrates, Ditsong National Museum of Natural History (Transvaal Museum), 432 Paul Kruger Street, Pretoria Central, Pretoria, South Africa
| | - Travis R Pickering
- Evolutionary Studies Institute, University of the Witwatersrand, Private Bag 3, Johannesburg, WITS, 2050, South Africa.,Department of Biology, Birmingham-Southern College, 900 Arkadelphia Road, Birmingham, AL, 35254, United States.,Department of Anthropology, University of Wisconsin, Madison, WI, 53706, United States
| | - Kristian J Carlson
- Evolutionary Studies Institute, University of the Witwatersrand, Private Bag 3, Johannesburg, WITS, 2050, South Africa.,Department of Integrative Anatomical Sciences, Keck School of Medicine, University of Southern California, 1975 Zonal Avenue, Los Angeles, CA, 90033, United States
| | - Robin H Crompton
- Evolutionary Studies Institute, University of the Witwatersrand, Private Bag 3, Johannesburg, WITS, 2050, South Africa.,Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, William Henry Duncan Building, W Derby Street, Liverpool, L7 8TX, United Kingdom
| | - Tea Jashashvili
- Evolutionary Studies Institute, University of the Witwatersrand, Private Bag 3, Johannesburg, WITS, 2050, South Africa.,Molecular Imaging Center, Department of Radiology, Keck School of Medicine, University of Southern California, 2250 Alcazar Street, Los Angeles, CA, 90033, United States.,Department of Geology and Paleontology, Georgian National Museum, 3 Shota Rustaveli Ave, T'bilisi, 0105, Georgia
| | - Laurent Bruxelles
- School of Geography, Archaeology and Environmental Studies, University of the Witwatersrand, Private Bag 3, Johannesburg, WITS, 2050, South Africa.,French National Institute for Preventive Archaeological Researches (INRAP), 561 rue Etienne Lenoir, 30900, Nîmes, France.,French Institute of South Africa (IFAS), USR 3336 CNRS, 62 Juta Street, Braamfontein, Johannesburg, 2001, South Africa
| | - Kudakwashe Jakata
- Evolutionary Studies Institute, University of the Witwatersrand, Private Bag 3, Johannesburg, WITS, 2050, South Africa
| | - Lunga Bam
- South African Nuclear Energy Corporation SOC Ltd. (Necsa), Elias Motsoaledi Street Ext. (Church Street West), R104, Pelindaba, North West Province, South Africa
| | - Luc Van Hoorebeke
- UGCT Department of Physics and Astronomy, Ghent University, Proeftuinstraat 86/N12, B-9000, Gent, Belgium
| | - Kathleen Kuman
- School of Geography, Archaeology and Environmental Studies, University of the Witwatersrand, Private Bag 3, Johannesburg, WITS, 2050, South Africa
| | - Dominic Stratford
- School of Geography, Archaeology and Environmental Studies, University of the Witwatersrand, Private Bag 3, Johannesburg, WITS, 2050, South Africa
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Plomp K, Viðarsdóttir US, Dobney K, Weston D, Collard M. Potential adaptations for bipedalism in the thoracic and lumbar vertebrae of Homo sapiens: A 3D comparative analysis. J Hum Evol 2019; 137:102693. [PMID: 31711026 DOI: 10.1016/j.jhevol.2019.102693] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2018] [Revised: 10/12/2019] [Accepted: 10/12/2019] [Indexed: 10/25/2022]
Abstract
A number of putative adaptations for bipedalism have been identified in the hominin spine. However, it is possible that some have been overlooked because only a few studies have used 3D and these studies have focused on cervical vertebrae. With this in mind, we used geometric morphometric techniques to compare the 3D shapes of three thoracic and two lumbar vertebrae of Homo sapiens, Pan troglodytes, Gorilla gorilla, and Pongo pygmaeus. The study had two goals. One was to confirm the existence of traits previously reported to distinguish the thoracic and lumbar vertebrae of H. sapiens from those of the great apes. The other was to, if possible, identify hitherto undescribed traits that differentiate H. sapiens thoracic and lumbar vertebrae from those of the great apes. Both goals were accomplished. Our analyses not only substantiated a number of traits that have previously been discussed in the literature but also identified four traits that have not been described before: (1) dorsoventrally shorter pedicles in the upper thoracic vertebrae; (2) dorsoventrally longer laminae in all five of the vertebrae examined; (3) longer transverse processes in the upper thoracic vertebrae; and (4) craniocaudally 'pinched' spinous process tips in all of the vertebrae examined. A review of the biomechanical literature suggests that most of the traits highlighted in our analyses can be plausibly linked to bipedalism, including three of the four new ones. As such, the present study not only sheds further light on the differences between the spines of H. sapiens and great apes but also enhances our understanding of how the shift to bipedalism affected the hominin vertebral column.
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Affiliation(s)
- Kimberly Plomp
- Department of Archaeology, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada; Department of Archaeology, Classics and Egyptology, University of Liverpool, 14 Abercromby Square, Liverpool, L69 7WZ, UK.
| | - Una Strand Viðarsdóttir
- Biomedical Center, University of Iceland, Læknagarður, Vatnsmýrarvegi 16, 101 Reykjavík, Iceland
| | - Keith Dobney
- Department of Archaeology, Classics and Egyptology, University of Liverpool, 14 Abercromby Square, Liverpool, L69 7WZ, UK
| | - Darlene Weston
- Department of Anthropology, University of British Columbia, 6303 NW Marine Drive, Vancouver, BC V6T 1Z1, Canada
| | - Mark Collard
- Department of Archaeology, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada.
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