Preface: Symposium on Stegosauria proceedings

Abstract

The Stegosauria, the plated dinosaurs, are medium to large-sized quadrupedal herbivorous ornithischians. They figureprominently in the history of dinosaur palaeontologybecause of their bizarre appearance: large body, tiny skullwithsmallcrenulatedteeth,hindlegstallerthantheforelegs,two rows of dorsally projecting erect dermal plates along theback and tail, and spikes at the end of the tail (Carpenter andGalton 2001). The most famous genus commonly used fortoys, movies, and known by many children (and adults!) isStegosaurus (‘‘roof lizard’’). It was named as early as 1877by O. C. Marsh from fossils of the Late Jurassic of westernNorth America. Most of the major features of our currentviewofStegosauruswerealreadyinplacewhenO.C.Marsh(1891) published the first skeletal reconstruction. Nonethe-less, from that time on, plated dinosaurs have been the least-studied dinosaurs and their incredible diversity has onlyrecently been recognized (Carpenter 2001). Meanwhile,stegosaurs have been recovered from all northern hemi-sphere continents and Africa. They are temporally restrictedto the Middle Jurassic to Early Cretaceous (Galton andUpchurch 2004; Maidment et al. 2008), with no definitivestegosaurian material known with confidence in youngersediments from anywhere in the world. In Switzerland, onlyone stegosaur bone (a proximal end of a femur) is known sofar (Meyer and Hunt 1998).Since 1990, the Sauriermusem Aathal carries out exca-vations in the Upper Jurassic Morrison Formation of theHowe-Stephens and Howe-Scott quarries (Howe Ranch,Big Horn Mountains, Wyoming, USA) (Ayer 2000).Besides the famous discoveries of specimens of Allosaurus,Diplodocus,orCamarasaurus some of the most completestegosaur skeletons of the world were also excavated overthe years. They include four specimens of stegosauridsreferred to cf. Stegosaurus armatus and Hesperosaurusmjosi, and nicknamed ‘‘Sarah’’, ‘‘Moritz’’ (Fig. 1), ‘‘Lilly’’,and ‘‘Victoria’’ (Siber and Mo¨ckli 2009). The latter spec-imen is nearly complete and includes an exquisitely-preserved skull, several hand-sized patches of skinimpressions, and several pronounced pathologies.Since many years Hans Jakob ‘‘Kirby’’ Siber, director ofthe Sauriermuseum Aathal, undertakes great efforts to makeaccessible the museum collection for scientific research, andit was the Sauriermuseum, which organized and financed the‘‘Symposium on Stegosauria’’. The main purpose of the‘‘Symposium on Stegosauria’’ was to bring together leadingstegosaurspecialists(http://www.sauriermuseum.ch/Dstegosymp.htm) from different parts of the world (Canada,Denmark, France, Germany, Japan, Portugal, Spain, Swit-zerland, UK, USA), in order to discuss recent advances andfuture directions in stegosaur research. Another purpose wasto study and discuss the extraordinary Aathal specimens,some of which are now on display in a special exhibition ofthe Sauriermuseum.During the symposium, 19 talks were given, covering abroad spectrum of research on stegosaur palaeontology suchas: history of discoveries and research, new finds, taxonomyandphylogeny,bonehistologyandontogeny,biomechanics,ichnology, taphonomy, and palaeoecology. Martin Sander(University of Bonn) chaired the sessions and there wasplenty of time for interesting and animated discussions.Eight contributions are presented in the proceedings, anumber of which re-evaluate historical finds, describe newfinds, highlight the difficulties in the––palaeontological––species concept of stegosaurs, and discuss taxonomy and