[Palaeontology, Vol. 58, Part 5, 2015, pp. 849–870] ENDOSKELETAL STRUCTURE IN CHEIROLEPIS (OSTEICHTHYES, ACTINOPTERYGII), AN EARLY RAY-FINNED FISH by SAM GILES1, MICHAEL I. COATES2,3, RUSSELL J. GARWOOD4,5, MARTIN D. BRAZEAU6,ROBERTATWOOD7, ZERINA JOHANSON8 and MATT FRIEDMAN1 1Department of Earth Sciences, University of Oxford, South Parks Road, Oxford, OX1 3AN, UK; e-mails:
[email protected],
[email protected] 2Department of Organismal Biology and Anatomy, University of Chicago, 1027 E. 57th Street, Chicago, IL 60637, USA; e-mail:
[email protected] 3Committee on Evolutionary Biology, University of Chicago, 1025 E. 57th Street, Chicago, IL 60637, USA 4School of Earth, Atmospheric and Environmental Sciences, The University of Manchester, Manchester, M13 9PL, UK; e-mail:
[email protected] 5The Manchester X-Ray Imaging Facility, School of Materials, The University of Manchester, Manchester, M13 9PL, UK 6Department of Life Sciences, Imperial College London, Silwood Park Campus, Buckhurst Road, Ascot, SL5 7PY, UK; e-mail:
[email protected] 7The Joint Engineering and Environmental Processing Beamline, Diamond Light Source, The Harwell Science and Innovation Campus, Didcot, OX11 0DE, UK; e-mail:
[email protected] 8Department of Earth Sciences, Natural History Museum, Cromwell Road, London, SW7 5BD, UK; e-mail:
[email protected] Typescript received 17 March 2015; accepted in revised form 30 May 2015 Abstract: As the sister lineage of all other actinopterygians, considered uncharacteristic of early actinopterygians, includ- the Middle to Late Devonian (Eifelian–Frasnian) Cheirolepis ing an uninvested dorsal aorta and imperforate propterygium, occupies a pivotal position in vertebrate phylogeny.