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Were Pterosaur Ancestors Bipedal Or Quadrupedal?: Morphometric, Functional, and Phylogenetic Considerations 21

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Were Pterosaur Ancestors Bipedal Or Quadrupedal?: Morphometric, Functional, and Phylogenetic Considerations 21 Zitteliana An International Journal of Palaeontology and Geobiology Series B/Reihe B Abhandlungen der Bayerischen Staatssammlung für Pa lä on to lo gie und Geologie B28 DAVID W. E. HONE & ERIC BUFFETAUT (Eds) Flugsaurier: pterosaur papers in honour of Peter Wellnhofer CONTENTS/INHALT Dedication 3 PETER WELLNHOFER A short history of pterosaur research 7 KEVIN PADIAN Were pterosaur ancestors bipedal or quadrupedal?: Morphometric, functional, and phylogenetic considerations 21 DAVID W. E. HONE & MICHAEL J. BENTON Contrasting supertree and total-evidence methods: the origin of the pterosaurs 35 PAUL M. BARRETT, RICHARD J. BUTLER, NICHOLAS P. EDWARDS & ANDREW R. MILNER Pterosaur distribution in time and space: an atlas 61 LORNA STEEL The palaeohistology of pterosaur bone: an overview 109 S. CHRISTOPHER BENNETT Morphological evolution of the wing of pterosaurs: myology and function 127 MARK P. WITTON A new approach to determining pterosaur body mass and its implications for pterosaur fl ight 143 MICHAEL B. HABIB Comparative evidence for quadrupedal launch in pterosaurs 159 ROSS A. ELGIN, CARLOS A. GRAU, COLIN PALMER, DAVID W. E. HONE, DOUGLAS GREENWELL & MICHAEL J. BENTON Aerodynamic characters of the cranial crest in Pteranodon 167 DAVID M. MARTILL & MARK P. WITTON Catastrophic failure in a pterosaur skull from the Cretaceous Santana Formation of Brazil 175 MARTIN LOCKLEY, JERALD D. HARRIS & LAURA MITCHELL A global overview of pterosaur ichnology: tracksite distribution in space and time 185 DAVID M. UNWIN & D. CHARLES DEEMING Pterosaur eggshell structure and its implications for pterosaur reproductive biology 199 DAVID M. MARTILL, MARK P. WITTON & ANDREW GALE Possible azhdarchoid pterosaur remains from the Coniacian (Late Cretaceous) of England 209 TAISSA RODRIGUES & ALEXANDER W. A. KELLNER Review of the pterodactyloid pterosaur Coloborhynchus 219 JUNCHANG LÜ, LI XU & QIANG JI Restudy of Liaoxipterus (Istiodactylidea: Pterosauria), with comments on the Chinese istiodactylid pterosaurs 229 DAVID M. MARTILL First pterosaur remains from the Exu Formation (Cretaceous) of the Araripe Basin, Brazil 243 ERIC BUFFETAUT Late Cretaceous pterosaurs from France: a review 249 Zitteliana B 28 255 Seiten München, 31.12.2008 ISSN 1612-4138 Editors-in-Chief/Herausgeber: Michael Krings, Gert Wörheide Production and Layout/Bildbearbeitung und Layout: Martine Focke Bayerische Staatssammlung für Paläontologie und Geologie Editorial Board A. Altenbach, München B.J. Axsmith, Mobile, AL F.T. Fürsich, Erlangen K. Heißig, München H. Kerp, Münster J. Kriwet, Stuttgart J.H. Lipps, Berkeley, CA T. Litt, Bonn A. Nützel, München O.W.M. Rauhut, München B. Reichenbacher, München J.W. Schopf, Los Angeles, CA G. Schweigert, Stuttgart F. Steininger, Eggenburg Richard-Wagner-Str. 10, D-80333 München, Deutschland http://www.palmuc.de/zitteliana email: [email protected] Für den Inhalt der Arbeiten sind die Autoren allein ver ant wort lich. Authors are solely responsible for the contents of their articles. Copyright © 2008 Bayerische Staassammlung für Pa lä on to lo gie und Geologie, München Die in der Zitteliana veröffentlichten Arbeiten sind urheberrechtlich geschützt. Nachdruck, Vervielfältigungen auf photomechanischem, elektronischem oder anderem Wege sowie die Anfertigung von Übersetzungen oder die Nut zung in Vorträgen, für Funk und Fernsehen oder im Internet bleiben – auch auszugsweise – vorbehalten und bedürfen der schriftlichen Ge neh mi gung durch die Bayerische Staatssammlung für Paläontologie und Geologie, München. ISSN 1612-4138 Druck: Gebr. Geiselberger GmbH, Altötting Cover Illustration: Modell eines Rhamphorhynchus aus dem Oberjura von Eichstätt. Entwurf: P. Wellnhofer, Modell: R. Liebreich, Foto und Collage: M. Schellenberger, L. Geißler, BSPG München. Umschlagbild: Reconstitution of a Rhamphorhynchus from the Upper Jurassic of Eichstätt, Bavaria. Concept: P. Wellnhofer; design: R. Liebreich; photograph and collage: M. Schellenberger, L. Geißler, BSPG Munich. 21 Zitteliana B28 21 - 33 4 Figs, 4 Tabs München, 31.12.2008 ISSN 1612 - 4138 Were pterosaur ancestors bipedal or quadrupedal?: Morphometric, functional, and phylogenetic considerations By Kevin Padian* Department of Integrative Biology and Museum of Paleontology, University of California, Berkeley, CA 94720, U.S.A. Manuscript received September 4, 2007; revised manuscript accepted February 27, 2008. Abstract Zusammenfassung Whereas some phylogenetic analyses have suggested that Obwohl manche Phylogenetische Analysen andeuten, pterosaurs evolved from basal archosauromorphs, most dass sich die Flugsaurier aus den basalen Archosauromorpha analyses have concluded that they are basal ornithodirans, entwickelt haben kommen die meisten Untersuchungen zu the sister group to dinosauromorphs. Independently, for dem Schluss, dass es sich um basale Ornithodira, eine Schwes- over a century it has been debated whether their typical tergruppe der Dinosauromorpha, handelt. Davon unabhängig mode of terrestrial progression was bipedal or quadrupedal. wird seit mehr als einem Jahrhundert darüber diskutiert In view of the fact that at least some pterodactyloid ptero- ob sie sich terrestrisch überwiegend biped oder quadruped saurs are now known to have made quadrupedal tracks, the fortbewegten. Da man heute weiß dass manche pterodactyle question persists whether pterosaurs evolved from bipedal Flugsaurier quadrupede Spuren hinterließen, bleibt die Frage or quadrupedal ancestors. Phylogenetic analyses suggest bestehen ob sie sich aus bipeden oder quadrupeden Vorfahren ambiguous polarity when outgroups are used to reconstruct entwickelt haben. Phylogenetische Analysen bieten keine ein- the ancestral state: basal archosauromorphs were presumably deutigen Ergebnisse wenn Außengruppen zur Rekonstruktion quadrupedal, whereas basal ornithodirans were presumably des Ahnenstatus miteinbezogen werden: basale Archosau- bipedal. Morphometric comparisons, however, suggest romorpha waren vermutlich quadruped, basale Ornithodira that basal pterosauromorphs were bipedal; that compared dagegen biped. Morphometrische Vergleiche deuten darauf to their pseudosuchian outgroups their hindlimbs became hin dass basale Flugsaurier biped waren. Demzufolge verlän- elongated relative to the trunk length, and the forelimbs gerten sich im Gegensatz zur Außengruppe der Pseudosuchia later lengthened as they assumed a role in aerial locomotion. die Hinterbeine relativ zur Schwanzlänge. Die Vorderbeine The humerus became elongated but the forearm increased verlängern sich vermutlich später für die Fortbewegung in its length more rapidly so that it exceeded the humerus in der Luft. Der Humerus wird verlängert, der Unterarm jedoch length and was usually one of the longest wing elements in verlängert sich schneller so dass er den Humerus an Länge non-pterodactyloids. Functional and ichnological evidence übertrifft und zum längsten Element im Flügel der nicht-pte- confi rms that the stance was erect and the gait parasagittal, as rodactylen Flugsaurier wird. Funktionelle und ichnologische in birds and other dinosaurs. Trackways also show that pte- Untersuchungen beweisen, dass ebenso wie bei Vögeln und rosaurs modifi ed their footfall patterns from the traditional anderen Dinosauriern die Haltung aufrecht und der Gang reptilian condition, suggesting that the habit was secondary. parasagittal war. Auch ihre Fussspuren lassen erkennen dass Comparing forelimb to hindimb lengths without considering sich das Schrittmuster von dem der ursprünglichen Reptilien other morphometric and phylogenetic contexts can provide ableitet, wenn man annimmt dass ihre Art sich fortzubewegen misleading indications of the evolution of limb length in the sekundär entstanden ist. Irreführende Hinweise in der Evolu- origin of pterosaurs. tion der Beinlänge am Ursprung der Flugsaurier können ent- stehen wenn man Vorderbeine und Hinterbeine, ohne andere Key words: Pterosauria, functional morphology, mor- morphometrische und phylogenetische Zusammenhänge zu phometrics, phylogeny, locomotion, evolution berücksichtigen, vergleicht. Schlüsselwörter: Flugsaurier, funktionelle Morphologie, Morphometrie, Phylogenie, Lokomotion, Evolution *E-mail: [email protected] 22 1. Introduction question of posture in the earliest pterosaurs and their ancestors. The holotype of Eudimorphodon cromptonellus has relatively Did pterosaurs evolve from bipedal or quadrupedal ance- short wings, forearms and tibiae, and long metatarsals, and the stors? There have been divergent analyses of the terrestrial proximal limb segments (humerus, ulna, femur, and tibia) are ability of pterosaurs (e.g., PADIAN 1983b, 2003; WELLNHOFER of nearly equal length. Although the specimen is probably a 1988; BENNETT 1997a; UNWIN 1997, 1999 and references the- juvenile individual, based on its osteohistological features, its rein), but the question of the ancestral condition has seldom proportions do not fi t the growth trajectories of other known been approached (PADIAN 1983b, 1991, 1997). Part of the contemporary pterosaurs, justifying its taxonomic separation answer lies in the kinematics of the joints of the hindlimb (JENKINS et al. 2001). The question is what its limb proportions (PADIAN 1983b; WELLNHOFER 1988; BENNETT 1997a), and may tell us about the condition in pterosaur ancestors, and for part in the morphometric ratios of forelimb and hindlimb this, some broader comparative context is necessary. elements. Some considerations have been based on whether the hindlimbs were involved in the wing, and the effect
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