New fossils of Australopithecus sediba reveal a nearly complete lower back

eLife

Jennifer Eyre¹  Jeffrey Spear²  Scott A Williams³  Renier Van Der Merwe⁴  Lee R Berger⁴  Peter Schmid⁵  Daniel García-Martínez⁶  Markus Bastir⁷  Steven E Churchill⁸  Shahed Nalla⁹  Kelly R Ostrofsky^1,10  Marc R Meyer^1,11  Gabrielle A Russo^1,12  Thomas Cody Prang^1,13  Christopher Yelverton^1,14  Mark Grabowski^1,15  Thierra K Nalley^1,16 

[1] Center for the Study of Human Origins, Department of Anthropology, New York University, New York, United States;Department of Anthropology, Bryn Mawr College, Bryn Mawr, United States;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;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;Centre for the Exploration of the Deep Human Journey, University of the Witwatersrand, Johannesburg, South Africa;Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa;Centre for the Exploration of the Deep Human Journey, University of the Witwatersrand, Johannesburg, South Africa;Centre for the Exploration of the Deep Human Journey, University of the Witwatersrand, Johannesburg, South Africa;Anthropological Institute and Museum, University of Zurich, Zurich, Switzerland;Centre for the Exploration of the Deep Human Journey, University of the Witwatersrand, Johannesburg, South Africa;Centro Nacional de Investigación sobre la Evolución Humana (CENIEH), Burgos, Spain;Departamento de Biodiversidad, Ecología y Evolución, Universidad Complutense de Madrid (UCM), Madrid, Spain;Centre for the Exploration of the Deep Human Journey, University of the Witwatersrand, Johannesburg, South Africa;Departamento de Paleobiología, Museo Nacional de Ciencias Naturales (CSIC), Madrid, Spain;Centre for the Exploration of the Deep Human Journey, University of the Witwatersrand, Johannesburg, South Africa;Department of Evolutionary Anthropology, Duke University, Durham, United States;Centre for the Exploration of the Deep Human Journey, University of the Witwatersrand, Johannesburg, South Africa;Department of Human Anatomy and Physiology, Faculty of Health Sciences, University of Johannesburg, Johannesburg, South Africa;Department of Anatomy, College of Osteopathic Medicine, New York Institute of Technology, Old Westbury, United States;Department of Anthropology, Chaffey College, Rancho Cucamonga, United States;Department of Anthropology, Stony Brook University, Stony Brook, United States;Department of Anthropology, Texas A&M University, College Station, United States;Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa;Department of Chiropractic, Faculty of Health Sciences, University of Johannesburg, Johannesburg, South Africa;Research Centre in Evolutionary Anthropology and Palaeoecology, Liverpool John Moores University, Liverpool, United Kingdom;Western University of Health Sciences, College of Osteopathic Medicine of the Pacific, Department of Medical Anatomical Sciences, Pomona, United States;

关键词: paleoanthropology;    human evolution;    bipedalism;    vertebral column;    lordosis;    upright posture;    Human;   

DOI  :  10.7554/eLife.70447

来源: eLife Sciences Publications, Ltd

【 摘 要 】

Adaptations of the lower back to bipedalism are frequently discussed but infrequently demonstrated in early fossil hominins. Newly discovered lumbar vertebrae contribute to a near-complete lower back of Malapa Hominin 2 (MH2), offering additional insights into posture and locomotion in Australopithecus sediba. We show that MH2 possessed a lower back consistent with lumbar lordosis and other adaptations to bipedalism, including an increase in the width of intervertebral articular facets from the upper to lower lumbar column (‘pyramidal configuration’). These results contrast with some recent work on lordosis in fossil hominins, where MH2 was argued to demonstrate no appreciable lordosis (‘hypolordosis’) similar to Neandertals. Our three-dimensional geometric morphometric (3D GM) analyses show that MH2’s nearly complete middle lumbar vertebra is human-like in overall shape but its vertebral body is somewhat intermediate in shape between modern humans and great apes. Additionally, it bears long, cranially and ventrally oriented costal (transverse) processes, implying powerful trunk musculature. We interpret this combination of features to indicate that A. sediba used its lower back in both bipedal and arboreal positional behaviors, as previously suggested based on multiple lines of evidence from other parts of the skeleton and reconstructed paleobiology of A. sediba.

【 授权许可】

CC BY