eprintid: 1557400 rev_number: 35 eprint_status: archive userid: 608 dir: disk0/01/55/74/00 datestamp: 2017-05-31 11:10:05 lastmod: 2021-10-06 22:48:33 status_changed: 2017-05-31 11:10:05 type: article metadata_visibility: show creators_name: Ward, CV creators_name: Nalley, TK creators_name: Spoor, F creators_name: Tafforeau, P creators_name: Alemseged, Z title: Thoracic vertebral count and thoracolumbar transition in Australopithecus afarensis ispublished: pub divisions: UCL divisions: B03 divisions: C03 divisions: F22 keywords: Australopithecus afarensis, Dikika, segmentation, thoracic, vertebrae note: This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions. abstract: The evolution of the human pattern of axial segmentation has been the focus of considerable discussion in paleoanthropology. Although several complete lumbar vertebral columns are known for early hominins, to date, no complete cervical or thoracic series has been recovered. Several partial skeletons have revealed that the thoracolumbar transition in early hominins differed from that of most extant apes and humans. Australopithecus africanus, Australopithecus sediba, and Homo erectus all had zygapophyseal facets that shift from thoracic-like to lumbar-like at the penultimate rib-bearing level, rather than the ultimate rib-bearing level, as in most humans and extant African apes. What has not been clear is whether Australopithecus had 12 thoracic vertebrae as in most humans, or 13 as in most African apes, and where the position of the thoracolumbar transitional element was. The discovery, preparation, and synchrotron scanning of the Australopithecus afarensis partial skeleton DIK-1-1, from Dikika, Ethiopia, provides the only known complete hominin cervical and thoracic vertebral column before 60,000 years ago. DIK-1-1 is the only known Australopithecus skeleton to preserve all seven cervical vertebrae and provides evidence for 12 thoracic vertebrae with a transition in facet morphology at the 11th thoracic level. The location of this transition, one segment cranial to the ultimate rib-bearing vertebra, also occurs in all other early hominins and is higher than in most humans or extant apes. At 3.3 million years ago, the DIK-1-1 skeleton is the earliest example of this distinctive and unusual pattern of axial segmentation. date: 2017-06-06 date_type: published official_url: http://doi.org/10.1073/pnas.1702229114 oa_status: green full_text_type: other language: eng primo: open primo_central: open_green article_type_text: Journal Article verified: verified_manual elements_id: 1296280 doi: 10.1073/pnas.1702229114 pii: 1702229114 lyricists_name: Spoor, Christiaan Frederik lyricists_id: CFSPO66 actors_name: Spoor, Christiaan actors_id: CFSPO66 actors_role: owner full_text_status: public publication: Proceedings of the National Academy of Sciences of the United States of America volume: 114 number: 23 pagerange: 6000-6004 event_location: United States issn: 1091-6490 citation: Ward, CV; Nalley, TK; Spoor, F; Tafforeau, P; Alemseged, Z; (2017) Thoracic vertebral count and thoracolumbar transition in Australopithecus afarensis. Proceedings of the National Academy of Sciences of the United States of America , 114 (23) pp. 6000-6004. 10.1073/pnas.1702229114 <https://doi.org/10.1073/pnas.1702229114>. Green open access document_url: https://discovery-pp.ucl.ac.uk/id/eprint/1557400/1/401745_1_unknown_upload_6554359_pmnlg8_text.pdf document_url: https://discovery-pp.ucl.ac.uk/id/eprint/1557400/7/401745_1_unknown_upload_6554377_1mm42z_fig2.pdf document_url: https://discovery-pp.ucl.ac.uk/id/eprint/1557400/14/401745_1_unknown_upload_6554376_wmnlhg_fig1.jpg