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Evolution and palaeobiology of pterosaurs

ERIC BUFFETAUT 1 & JEAN-MICHEL MAZIN 2

1Centre National de la Recherche Scientifique, 16 cour du Li~gat, 75013 Paris, France 2Centre National de la Recherche Scientifique, UMR 6046, Laboratoire de G~obiologie, Biochronologie et PaI~ontologie humaine, Universit~ de Poitiers, 40 avenue du Recteur Pineau, 86022 Poitiers, France

The first scientific description of a pterosaur was course, but that of the pterosaurs is still conspicu- published in 1784 by Cosimo Alessandro Collini, a ously incomplete, because it is strongly influenced former secretary of Voltaire and at that time curator by the existence of Konservat-Lagerstdtten, fossil of the natural history cabinet of Karl Theodor, localities with exceptional preservation, which have Elector of Palatinate and Bavaria. The specimen led to the preservation of the fragile, hollow-boned came from one of the main sources of such fossils, skeletons of these flying reptiles. The Late Triassic the Late Jurassic lithographic limestones of northern bituminous limestones of northern Italy, the Liassic Bavaria, and Collini, after much deliberation, inter- bituminous shales of southern Germany, the Late preted it as the skeleton of an unknown marine crea- Jurassic lithographic limestones of Bavaria, the ture (Collini 1784). Early Cretaceous nodules of Brazil, and the fine- In 1801, Georges Cuvier, on the basis of Collini's grained Late Cretaceous chalk of the central United description and figure, identified the mysterious States are well-known examples of formations animal as a flying reptile (Cuvier 1801), for which he which have yielded a wealth of well-preserved pter- later coined the name 'Ptero-Dactyle' (Cuvier 1809). osaur specimens. In rocks formed under more usual Cuvier's basically correct interpretation of the conditions, pterosaur specimens tend to be scanty 'winged finger' marked the beginning of the study of and fragmentary. As a result, the evolutionary pterosaurs as an extinct group of flying reptiles. history of pterosaurs is still full of gaps, or time In the two centuries which have elapsed since intervals, during which the group is poorly repre- those first efforts to understand what have been con- sented, separating periods during which good sidered bizarre fossils, the study of pterosaurs has material was preserved under more or less excep- developed enormously. Some of the basic questions tional taphonomical conditions. Things, however, about them have long been solved: pterosaurs were are changing rather fast, as new specimens are neither birds, nor bats, as was suggested by various being found both in newly discovered Konservat- authors of the early nineteenth century, but a peculiar Lagerstdtten, such as the Early Cretaceous Yixian group of vertebrates which acquired the ability to fly Formation of northeastern China, and in other for- in an original way, using a membrane attached to a mations, in which pterosaur fossils may be more single finger of the hand. From the few fossils from fragmentary but are nonetheless important. Some of the Bavarian lithographic limestones known to the papers in this volume are thus descriptions of Cuvier and his contemporaries, the number of ptero- new pterosaur fossils from various parts of the world saur specimens has increased enormously, starting and from various stages of the Mesozoic: the Late with the Early Jurassic specimens from Lyme Regis Triassic of Austria (Wellnhofer), the Late Jurassic found by Mary Anning in the 1820s and first of the western United States (Carpenter et aL); the described by Buckland (1829), to the present day, Early Cretaceous of Brazil (Frey et aL) and when more than 60 genera have been found all over Venezuela (Kenner & Moody); and the Late the world (see the review by Wellnhofer 1991). It has Cretaceous of Morocco (Pereda-Suberbiola et al.) now become obvious that pterosaurs, although built and Romania (Buffetaut et al.). on a fairly uniform basic type, showed considerable One of the main problems about pterosaurs is diversity in terms of size and adaptations. However, their origin and early evolutionary history. Triassic despite considerable advances in our knowledge of pterosaurs in particular have been known only for pterosaurs, many questions and problems remain. the last 30 years, and yet these early forms, although The aim of this volume is to bring together papers already fully fledged pterosaurs, are of obvious which attempt to shed some light on various aspects importance for our understanding of the beginnings of pterosaurs as fossil organisms, with special of the group. Both a report of a new find from Austria emphasis on their evolution and palaeobiology. (Wellnhofer) and a review of Triassic pterosaurs A first and important aspect is that the fossil (Daila Veechia) address this question in the present record of pterosaurs is far from being completely volume. More generally, it is only recently that the known. No fossil record can be known entirely, of evolutionary history of pterosaurs has begun to be

From: BUFFETAUT,E. & MAZe, J-M. (eds) 2003. Evolution and Palaeobiology of Pterosaurs. Geological Society, London, Special Publications, 217, 1-3.0305-8719/03/$15 9 The Geological Societyof London 2003. Downloaded from http://sp.lyellcollection.org/ by guest on September 30, 2021

2 E.H. BUFFETAUT & J-M. MAZIN investigated using the modern concepts of phylo- France) clearly illustrates the quadrupedal locomo- genetic systematics. Two papers in this volume tion of pterodactyloid pterosaurs (Mazin et al.). (Kellner; Unwin) propose alternative comprehen- Pterosaurs were, however, not only able to fly and sive phylogenies of the Pterosauria, which will walk; they could also swim, as shown by ichnologi- undoubtedly serve as a basis for further discussions. cal evidence from the Late Jurassic of North Besides their phylogeny, an enduring problem has America (Loekley & Wright), which also provides been pterosaur biology. Because they have no real clues as to their feeding behaviour. Pterosaur track- equivalent in the present living world, the mode of ways have been the subject of much controversy and life of pterosaurs has been the subject of much specu- their parataxonomy has become considerably entan- lation ever since it was recognized that they were gled, hence the need for a critical review advocating flying animals. A detailed analysis of various aspects drastic simplification (Billon-Bruyat & Mazin). of their skeletal anatomy is a prerequisite to an A further way to explore the palaeobiology of understanding of the way in which they functioned, pterosaurs is the study of their bone histology. Inter- as illustrated by a study of the morphological evolu- estingly, this approach was pioneered as early as the tion of their pectoral girdle (Bennett), obviously a mid-nineteenth century by the British researchers fundamental part of the anatomy of any flying verte- James Bowerbank (1848) and John Quekett (1849a, brate. As discussed, much of what we know about b). Some of Quekett's thin sections have survived pterosaurs depends on preservation, and even taxa until the present day (despite the bombing of the which have been known for a long time can yield Royal College of Surgeons, where they were kept, remarkable new information, particularly when good during the Second World War), and they are rede- specimens are prepared using modern techniques, as scribed and reinterpreted here (Steel). Pterosaur exemplified by the description of axial pneumaticity fossils from the Brazilian Konservat-Lagerstiitten in Rhamphorhynchus (Bonde & Christiansen), a are excellent material for histological investigations, taxon first described by Hermann von Meyer in as illustrated by a study on differential growth rates 1847. Careful and painstaking preparation of exqui- based on such specimens (Sayfio). sitely preserved specimens has also contributed Much indeed can be learned from pterosaur immensely to our knowledge of the soft parts of pter- fossils, and the description of a new ornithocheirid osaurs, which are of obvious importance for our taxon from Brazil also includes an interesting piece understanding of the biology and biomechanics of of forensic palaeontology that provides convincing animals in which the flying apparatus consisted of a evidence as to the cause of death of what is now the wing membrane, which in most instances has not type specimen (Frey et al.). been preserved. As described in one of the papers Although they are not very common fossils, ptero- (Frey et al.), anatomical details as delicate as blood saurs were an important group of vertebrates during vessels have sometimes been preserved and shed the Mesozoic, and their unusual and interesting unexpected light on various aspects of pterosaur adaptations are attracting the attention of a growing biology. number of palaeontologists. The aim of the present Ever since Cuvier realized that pterosaurs were volume is to give an idea of the diverse topics winged reptiles, their locomotion, both in the air and addressed by researchers working on these fascinat- on the ground, has been the subject of much contro- ing animals and to encourage further research and versy. The flight of pterosaurs can be investigated discussion. mainly on the basis of their skeletal anatomy, but comparisons with man-made flying machines can lead to interesting conclusions about the existence of References various types of flight adaptations in this group of extinct vertebrates (Frey et al.). Locomotion on the BOWERBANK,J. S. 1848. Microscopical observations on the ground is a different matter, and totally divergent structure of the bones of Pterodactylus giganteus and interpretations have been put forward on purely other fossil animals. Quarterly Journal of the morphological grounds, with some authors support- Geological Society, London, 13, 2-10. ing a bipedal gait, while others favoured a quadru- BUCKLAND,W. 1829. On the discovery of a new species of pedal stance. The matter has largely been solved pterodactyle in the Lias at Lyme Regis. Transactions by the discovery and study of pterosaur footprints of the Geological Society, London, 3, 217-222. and trackways, in many parts of the world, which CoLu~, C. 1784. Sur quelques zoolithes du Cabinet provide direct evidence as to how these animals d'Histoire Naturelle de S.A.S.E. Palatine et de Bavi~re, h Mannheim. Acta Academiae Theodoro- moved when on the ground. A new discovery of pter- Palatinae, Mannheim, Pars Physica, 5, 58-103. osaur footprints from the Late Cretaceous of Mexico CUVIER, G. 1801. Extrait d'un ouvrage sur les esp~ces de is described here (Rodriguez-de la Rosa), and a quadnlp6des dont on a trouv6 les ossemens darts Fin- detailed analysis based on the remarkable trackways trrieur de la terre. Journal de Physique, de Chimie et from the Late Jurassic of Crayssac (southwestern d'Histoire Naturelle, 52, 253-267. Downloaded from http://sp.lyellcollection.org/ by guest on September 30, 2021

INTRODUCTION 3

CUVIER, G. 1809. M6moire sur le squelette fossile d'un composing the skeleton in the four great classes of reptile volant des environs d'Aichstedt, que quelques animals, viz., mammals, birds, reptiles and fishes, naturalistes ont pris pour un oiseau, et dont nous with some remarks on the great value of the knowl- formons un genre de Sauriens, sous le nora de Ptero- edge of such structure in determining the affinities of Dactyle. Annales du Museum national d'Histoire minute fragments of organic remains. Transactions of Naturelle, Paris, 13, 424--437. the Microscopical Society, London, 2, 46-58. MEYER, H. VON. 1847. Homoeosaurus maximiliani und QUEKETT, J. T. 1849b. Additional observations on the inti- Rhamphorhynchus (Pterodactylus) longicaudus, zwei mate structure of bone. Transactions of the fossile Reptilien aus dem Kalkschiefer yon Microscopical Society, London, 2, 59-64. Solenhofen. Schmerber, Frankfurt. WELLNHOFER, P. 1991. The Illustrated Encyclopedia of QuEI~a-r, J. T. 1849a. On the intimate structure of bone, as Pterosaurs. Salamander, London, 192 pp.