SPRINGER BRIEFS IN EARTH SYSTEM SCIENCES SOUTH AMERICA AND THE SOUTHERN HEMISPHERE Alberto Luis Cione Germán Mariano Gasparini Esteban Soibelzon Leopoldo Héctor Soibelzon Eduardo Pedro Tonni The Great American Biotic Interchange A South American Perspective 123 SpringerBriefs in Earth System Sciences South America and the Southern Hemisphere Series editors Jorge Rabassa, Ushuaia, Argentina Gerrit Lohmann, Bremen, Germany Justus Notholt, Bremen, Germany Lawrence A. Mysak, Montreal, Canada Vikram Unnithan, Bremen, Germany More information about this series at http://www.springer.com/series/10032 Pleistocene continental beds cropping out in the coastal cliffs south of Miramar, Buenos Aires Province. Note the chimango, a terrestrial bird at the left, and a gull, a marine bird at the right. Photo by Esteban Soibelzon Alberto Luis Cione · Germán Mariano Gasparini Esteban Soibelzon · Leopoldo Héctor Soibelzon Eduardo Pedro Tonni The Great American Biotic Interchange A South American Perspective 1 3 Alberto Luis Cione Leopoldo Héctor Soibelzon División Paleontología Vertebrados, División Paleontología Vertebrados, Museo de La Plata, Facultad de Museo de La Plata, Facultad de Ciencias Naturales y Museo Ciencias Naturales y Museo UNLP UNLP La Plata La Plata Argentina Argentina Germán Mariano Gasparini Eduardo Pedro Tonni División Paleontología Vertebrados, División Paleontología Vertebrados, Museo de La Plata, Facultad de Museo de La Plata, Facultad de Ciencias Naturales y Museo Ciencias Naturales y Museo UNLP UNLP La Plata La Plata Argentina Argentina Esteban Soibelzon División Paleontología Vertebrados, Museo de La Plata, Facultad de Ciencias Naturales y Museo UNLP La Plata Argentina ISSN 2191-589X ISSN 2191-5903 (electronic) SpringerBriefs in Earth System Sciences ISBN 978-94-017-9791-7 ISBN 978-94-017-9792-4 (eBook) DOI 10.1007/978-94-017-9792-4 Library of Congress Control Number: 2015934918 Springer Dordrecht Heidelberg New York London © The Author(s) 2015 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, express or implied, with respect to the material contained herein or for any errors or omissions that may have been made. Printed on acid-free paper Springer Science+Business Media B.V. Dordrecht is part of Springer Science+Business Media (www.springer.com) The most emblematic South American mammals are the guanaco, the tapir, and the spectacled bear. However, the closest ancestors of these animals did not originate in the continent: They were recent immigrants from North America. Yes, we got a problem: The evidence is at the bottom of the bottle and we are not drunks Preface The Great American Biotic Interchange (GABI) between North and South America is one of the most important events in the history of land mammals. The first authors that considered the interchange between the Americas were Wallace, Ameghino, and few others as early as the second half of the nineteenth century. Notwithstanding that a huge effort was made by thousands of paleontologists, zoologists, botanists, geologists, and professionals of other disciplines, we are far from having a precise panorama about one of the most important events in the his- tory of mammals. However, we are confident that a more complete survey of mammal bearing units in southern South America as well as discovering others in the central and northern Andes and Central America will give us the factual evidence for propos- ing, confirming, or rejecting many hypotheses. Moreover, the expanding molecular studies will provide the minimum age for the origin of many endemic clades of North American families whose first appearance is not adequately explained. In this book, we consider the extinction of megafauna in South America as a part of GABI. Several paleontologists (including the authors of this book) are commited to the study of the process that modified permanently the composi- tion and distribution of land mammals in South America. The entrance of hunter- gatherers at the end of the Pleistocene occasioned the spectacular extinction of megafauna. However, this process is being completed by modern man. For this, research on recent distribution of vertebrates in South America has to be accel- erated. During the last twentieth and twenty-first centuries, terrestrial and aquatic environments changed radically because modern human activities occasioned extinction, pseudoextinction, and alteration of distribution of many mammals. This disruption might make conventional and molecular studies of historical patterns and relationships between different lineages extremely difficult. However, fossils are still in the rocks. They are waiting for us to find them, unearth them, and make them drops of light for explaining the origin of a treasure in danger: the richest land mammal fauna of the world. vii viii Preface The authors thank Jorge Oscar Rabassa (Series Springer Editor for South America) for the invitation to publish this book and for critical review of an early draft of the manuscript; Jorge González for the drawings; Marcela Tomeo (Museo de La Plata) for the maps and figures; Mariano Donato, Jorge Morrone, Cecilia Deschamps, and Alfredo Zurita for valuable information; and Cecilia Deschamps (MLP) for language correction and revision of a former manuscript. We also thank Facultad de Ciencias Naturales y Museo (UNLP) and the Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET). This book was partially funded by PICT 2010-0804 and PIP 0436. Contents 1 Introduction ................................................ 1 References .................................................. 7 2 Continental Relationships, Chronostratigraphy, Climates, and Mammalian Biogeography of Southern South America Since Late Miocene .......................................... 9 2.1 General Continental Relationships of South America ............ 9 2.2 Evolution of the Physical Connection Between Central and South America ....................................... 12 2.3 History and Conceptual Framework of Mammal Stratigraphy of the Southern Cone of South America Since the Miocene ....... 14 2.3.1 The Stratigraphy of the Pampas ...................... 14 2.3.2 Comments on the Pampean Loess and Lithostratigraphic Units of the Pampean Region ........................ 19 2.4 The Late Cenozoic Mammals of the Pampean Region. A Biostratigraphical Point of View .......................... 20 2.4.1 Biozone of Macrochorobates scalabrinii ............... 21 2.4.2 Biozone of Eumysops Laeviplicatus ................... 23 2.4.3 Biozone of Paraglyptodon chapadmalensis ............. 23 2.4.4 Biozone of Platygonus scagliai ...................... 25 2.4.5 Biozone of Akodon (Akodon) lorenzinii ................ 25 2.4.6 Biozone of Ctenomys chapalmalensis ................. 26 2.4.7 Biozone of Mesotherium cristatum ................... 28 2.4.8 Biozone of Megatherium americanum ................. 29 2.4.9 Biozone of Equus (Amerhippus) neogaeus ............. 30 2.4.10 Biozone of Lagostomus maximus ..................... 32 2.4.11 An Alternative Scheme for the Late Miocene Based on Biochronology ........................... 35 ix x Contents 2.5 Paleoclimatology of the Southern Cone of South America Since the Miocene ....................................... 36 2.5.1 Climates in Patagonia Since the Miocene .............. 36 2.5.2 Climates in the Pampean Region from the Late Miocene to the Pliocene ................................... 38 2.5.3 Climates in the Pampean Region During the Quaternary ... 39 2.6 Biogeography of the Recent Mammals of South America ......... 44 2.6.1 Biogeography of Argentina ......................... 49 2.6.2 The Pampa Ecoregion. 51 2.6.3 Mammals Introduced by Man ....................... 53 References .................................................. 53 3 The GABI in Southern South America .......................... 71 3.1 Short History of the Interchange and the Great American Biotic Interchange (GABI) Concept. 71 3.2 The GABI Chronology and Dynamics ........................ 73 3.2.1 First Record of Taxa of North American Origin in Southern South America Gives the General Pattern but does not Explain the Details. 73 3.2.2 Integration of South American Mammalian Faunas: The Coexistence of Native and Immigrant Taxa ......... 78 References .................................................. 90 Index ......................................................... 97 Chapter 1 Introduction Abstract The Great American Biotic Interchange (GABI) between North and South America is one of the most important events in the history of land mam- mals. The interchange occurred in several phases during more than