PATAGONIAN MESOZOIC REPTILES

GASPARINI, Z., SALGADO, L., CORIA, R.A.

Indiana University Press

Lugar: Bloomington; Año: 2007 p. 374

978-0-253-34857-9

 The word “Patagonia” is usually linked to vast deserts wedged between the South Atlantic and the Andes. The latter separates it from Chile, where, in contrast, we can find at the same latitudes, some of the most humid forests anywhere. However, the desert or semiarid Argentinean Patagonia and the humid Chilean forests are the consequence of a geologic history shared through million years. A significant portion of this history occurs during the Mesozoic. Distant, but at the same time seducing, Patagonia has been, since its discovery by the European explorers, but especially since the nineteenth Century, one of the most attractive places for explorers and particularly to paleontologists.  The amazing taxonomic diversity, the temporal and geographic broadness of the fossil record, and the variety of paleoenvironments (from ancient deserts to placid seas) all contribute in making Patagonia the centerpiece reference for Gondwanan Mesozoic reptiles. The first Patagonian geological and paleontological studies were mainly conducted on invertebrates and mammals. Other vertebrates did not draw attention and detailed analysis were missed until the publication in 1929 of world famous monograph by F. von Huene “Los saurisquios y Ornitisquios del Cretáceo Argentino” (The Saurischians and Ornithischians from the Argentinean Cretaceous). Nonetheless, several decades passed until the discovery of other non-mammalian tetrapods proved that Patagonia veiled an invaluable part of the evolutionary history of vertebrates. In current days, some 40 years after the first Patagonian extinct reptiles discoveries, and almost in a blasting way, Patagonia turned to be a landmark as “The land of dinosaurs”. These amazing terrestrial vertebrates are the definitive icon of Mesozoic vertebrates, and Patagonia has plenty of stories to tell about them – not only in regard of dinosaurs and their closest relatives, the birds- but also about other reptiles that lived in Patagonian both emerged lands and seas. The discoveries and subsequent studies of Patagonian Mesozoic reptiles were impelled mainly by Rodolfo Casamiquela in the 1960’s and 70’s, and later by José Bonaparte. Both provided decisive encouraging for disciples and students, who kept carrying on the search. Many of those former students are included as authors in the present this volume. Patagonian Mesozoic Reptiles goals putting together in a single volume and for first time, our current knowledge about these fossils. The body of information accumulated during the last one hundred years is not always available for the international scientific community because of distribution deficiencies of journals, linguistic limitations, or plain awareness of available data. This book aims to supply up-dated information about the evolution of Patagonia and its reptiles - always compared with other faunas from different corners of the planet. The title itself provides the scope of this book. From a geographical point of view, Patagonia provides a distinct and complementary perspective to those of other regions from both Gondwana and Laurasia, in terms of the evolution of life and the associated landmasses. In turn, the Mesozoic constitutes a key chapter of the geological history of this region, from both tectonic and paleontological points of view. We have included in this volume those taxa involved within the modern phylogenetic definition of Reptilia (“the most inclusive clade containing Lacerta agilis and Crocodylus niloticus but not Homo sapiens”, Modesto and Anderson 2004). Although not included in this definition, we have included in Chapter 13 a series of footprints assigned to mammal-like reptiles of the Triassic of Río Negro (Calibarichnus, Palaciosichnus, Rogerbaletichnus, Gallegosichnus), but not footprints attributed to mammals from the Jurassic of Santa Cruz (Ameghinichnus) (Casamiquela 1964). Patagonian Mesozoic Reptiles is organized in chapters written by different specialists in the respective subjects. Chapter 1 deals with the early history of the studies of fossil reptiles of Patagonia, most of which were known from circumstantial findings, framed by scientific projects traditionally devoted to the study of Tertiary and Quaternary mammals. In this context, the history of the men that made the discoveries and/or studies cannot be ignored. Indeed, they all have been truly epical because of the operational limitations conditioned by working in vast desserts in a developing country. The brothers Carlos and Florentino Ameghino, Santiago Roth, Richard Lydekker, John B. Hacther, Friedrich von Huene, and even the myth of the living plesiosaur of Patagonia (the “Nessie” of these latitudes) are part of that flavored and poorly known history. The Chapter II presents the paleogeographic evolution of Patagonia and the main depositional systems of its sedimentary basins through a series of maps plotted on a palinspastic plate reconstructions. This chapter provides the paleogeographic and paleoenvironmental frame for the Mesozoic of Patagonia and the following chapters. In Chapters (3-12) the systematic approach of the different Reptile clades represented in the Mesozoic of Patagonia is accomplished. In all of them the type and referred material of each taxon is detailed, with geographic and chronological provenance. In addition, diagnosis, in many cases new or modified, are included, together with extensive comments that each author considered necessary on different topics of the biology or evolutionary history of each group. These differences are due to the main research trends developed by the authors. The Chapter 13 includes the information supplied by the paleoichnology. Finally, Chapter 14, and on the basis of the previous chapters, is an overview on the reptilian Mesozoic faunal successions, in which some discontinuities, turnovers and diversifications, may be observed, most of which are related to the main geotectonic events that affected Patagonia during the Mesozoic. All the chapters of this volume have been reviewed by colleagues that generously contributed to the improvement of their quality, to whom the editors are especially indebted: N. Bardet (Musée National d´Histoire Naturelle, France), M. Bond (Museo de La Plata, La Plata, Argentina), C. Brochu (University of Iowa, USA), J. I. Canudo (Universidad de Zaragoza, Spain), M. Carrano (Smithsonian Institution, Washington DC, USA), I. S. Carvalho (Universidade Federal Rio de Janeiro, Brazil), J. Clark (George Washington University, Washington, USA), E. Gaffney (Natural History Museum, New York, USA), P. Galton (University of Bridgeport, Bridgeport, USA), A. Kellner (Universidade Federal Rio de Janeiro, Brazil), M. Lamanna (Carnegie Museum of Natural History, Pittsburgh, USA), O. Limarino (Buenos Aires University, Argentina), M. Lockley (University of Colorado at Denver, USA), J. Massare (SUNY College, Brockport NY, USA), C. A. Meyer (Geologisch- Palaeontologisches Institut Basel, Basel, Switzerland), F. Novas (Museo Argentino de Ciencias Naturales, Buenos Aires, Argentina), K. Padian (University of California, Berkeley, USA), M. J. Parham (University of California, Berkeley), J. C. Rage (Museum National d´Histoire Naturelle, France), S. Sachs (Institut für Paläontologie, Freie Universität Berlin),  J. D. Scanlon (Riversleigh Fossils Centre, Mount Isa, Australia), E. Tonni (Museo de La Plata, Argentina), D. Weishampel (John Hopkins University, Baltimore, USA), J. Wilson (University of Michigan, Ann Arbor, USA). Likewise, the editors appreciate the collaboration of the Argentinean artists: Jorge González, Carlos Papolio and Oscar Campos for generously giving the reconstructions of reptiles and environments included in the Insert. Some volunteer collaborators like A. Paulina Carabajal, Liliana Rikemberg (Museo “Carmen Funes”), Prebiterio Pacheco (Universidad Nacional del Comahue), Phill Currie (Royal Tyrrell Museum), and Cecilia Deschamps (Museo de La Plata) made possible handling many aspects of the formatting of this volume checking manuscripts, translating to English, mailing, filing and supplying permanent support and enthusiasm. Finally we specially want to thank the continuous help and orientation given by the Indiana University Press, Editorial Director Robert J. Sloan who patiently accompanied the developing of this contribution.    References Cited    Casamiquela, R. M. 1964. Estudios icnológicos. Problemas y métodos de la icnología con aplicación al estudio de pisadas mesozoicas (Reptilia, Mammalia) de la Patagonia. Buenos Aires. Colegio Industrial Pío IX,  229 pp. 71 figs., 26 pls. Modesto, S. P., and J. S. Anderson. 2004. The phylogenetic definition of Reptilia. Systematic Biology 53 (5): 815-821.