Pterosaur Eggshell Structure and Its Implications for Pterosaur Reproductive Biology 199

Pterosaur Eggshell Structure and Its Implications for Pterosaur Reproductive Biology 199

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. 199 Zitteliana B28 199-207 5 Figs München, 31.12.2008 ISSN 1612 - 4138 Pterosaur eggshell structure and its implications for pterosaur reproductive biology By David M. Unwin1* & D. Charles Deeming2 1Department of Museum Studies, University of Leicester, 103-105 Princess Road East, Leicester, LE1 7LG, UK 2Department of Biological Sciences, University of Lincoln, Riseholme Park, Lincoln, LN2 2LG, UK Manuscript received February 01, 2008; revised manuscript accepted April 01, 2008. Abstract die biegsame Eierschalen legen. Alle drei Beispiele ähneln den pergamentschaligen Eiern anderer Schuppenkriechtiere, zeigen The recent discovery of pterosaur eggs containing embryos allerdings Unterschiede in der Verkalkungsrate der äußeren has provided important evidence regarding the structure of pte- Hülle, die auch unter Schuppenkriechtierarten variiert. Es rosaur eggshell. Two eggs, from the same locality and horizon ist unwahrscheinlich, dass die pergamentschaligen Eier der in China, have a shell that appears to have been parchment-like Flugsaurier durch direkten Kontakt mit den Körpern der and pliable with no detectable mineralised calcareous compo- Eltern gebrütet worden sind, da das Risiko einer Beschädi- nent. A third egg, from Argentina, preserves evidence of a single gung der Eier besteht. Aufgrund der hohen Permeabilität layer of calcite. This is only 30 microns in thickness, however, eines pergamentartigen Eies, wäre ein Vergraben in einer sehr and thus very much thinner than mineralised layers reported in feuchten Umgebung, wie Sand, Erde oder vielleicht in Laub turtles that lay pliable-shelled eggs. All three examples resemble nötig gewesen, um ein Austrocknen während der Brutzeit zu the parchment-shelled eggs of squamate reptiles, but exhibit verhindern. Folglich liegt die Vermutung nahe, dass sich die variation in the degree of calcifi cation of the outer surface, Flugsauriereier in einer thermischen Umgebung entwickelt which also varies between squamate species. It seems unlikely haben; nahe der Umgebungstemperatur und wahrscheinlich that the parchment-shelled eggs of pterosaurs were incubated anfällig gegenüber Temperaturschwankungen. by direct contact with the body of a parent because of the risk of crushing the egg. Moreover, the likely high permeability of Schlüsselwörter: Argentinien, China, Ei, Eierschale, Em- a parchment-like eggshell would have required burial in a very bryo, Inkubation, Pterosaurier humid environment, such as sand, soil, or perhaps in mounds of rotting vegetation, to prevent desiccation during incubation. Consequently, pterosaur eggs are likely to have developed in 1. Introduction a thermal environment close to ambient temperatures and probably subject to some temperature variation. Pterosaurs are an enigmatic group of extinct fl ying reptiles with a fossil record that extends from the Late Triassic to the Key words: Argentina, China, egg, eggshell, embryo, in- end of the Cretaceous (e.g. WELLNHOFER 1991; BENNETT 1999; cubation, pterosaur NAISH & MARTILL 2003; UNWIN 2005). Many aspects of the palaeobiology of this group remain poorly understood, either because of the patchy and incomplete nature of the pterosaur Zusammenfassung fossil record, or because they are not preserved at all. Such was the case, until recently, for pterosaur reproductive biology, Die neueste Entdeckung von Flugsauriereiern, einschließ- which in the absence of any fossil evidence for pre-hatching lich Embryos, haben uns wichtige Hinweise über die Struktur stages was confi ned to speculation, much of it drawing upon von Flugsauriereischalen geliefert. Zwei solche Eier aus China, ill-founded analogies with birds (e.g. HALSTEAD & HALSTEAD welche am gleichen Fundort und in der gleichen Schicht ge- 1985). funden worden sind, besitzen eine biegsame, pergamentartige In 2004 descriptions of three pterosaur eggs, each with an Schale ohne sichtbare mineralisierte Komponenten. Ein drittes embryo, were published in the science journal Nature. The fi rst Ei aus Argentinien weist ein dünne Schicht Calcit auf. Diese ist of these reported on a well preserved egg, consisting of part lediglich 30 µm dick und damit viel dünner als die mineralisierte and counterpart, measuring 53 by 41 mm (estimated mass of Schichten, wie sie bei Meeresschildkröten gesichtet wurden, 50 g based on formula for symmetrical elongated crocodilian *Author for correspondence and reprint requests; E-mail: [email protected] 200 eggs [DEEMING & FERGUSON 1990]) and containing a complete, a long-standing mystery regarding oviparity or viviparity in naturally articulated embryo (WANG & ZHOU 2004; Figs 1, 2). pterosaurs (WELLNHOFER 1991; UNWIN 2005). In this paper we The fossil was found at the locality of Jingangshan in Liaoning focus on another signifi cant feature of these fossils, the nature Province, China, in lacustrine shales of the Jingangshan beds, of the eggshell, only brief details of which have appeared so which lie within the upper part of the Yixian Formation (WANG & ZHOU 2003) dated at approximately 121 mya (e.g. SMITH et al. 1995; JI et al. 2004) and thus Lower Cretaceous (Aptian) in age (GRADSTEIN et al. 2005). The same locality has yielded several other vertebrates (e.g. ZHANG & JIN 2003; ZHANG & ZHOU 2004; EVANS & WANG 2005; UNWIN et al. 2006) inclu- ding an avian embryo (ZHOU & ZHANG 2004). Anatomical features, including details of the dentition and the shape of the humerus, and proportions of limb elements, in particular the remarkably short metatarsus, permit IVPP V13758 to be assigned to the Ornithocheiridae (WANG

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