The Great American Biotic Interchange

Two rather different elements combine to explain the origin of this volume: one scientific and one personal. The broader of the two is the scientific basis-the time for such a volume had arrived. Geology had made remarkable progress toward an understanding of the phys ical history of the Caribbean Basin for the last 100 million years or so. On the biological side, many new discoveries had elucidated the distributional history of terrestrial orga nisms in and between the two Americas. Geological and biological data had been combined to yield the timing of important events with unprecedented resolution. Clearly, when each of two broad disciplines is making notable advances and when each provides new insights for the other, the rewards of cross-disciplinary contacts increase exponentially. The present volume represents an attempt to bring together a group of geologists, paleontologists and biologists capable of exploiting this opportunity through presentation of an interdisciplinary synthesis of evidence and hypothesis concerning interamerican connections during the Cretaceous and Cenozoic. Advances in plate tectonics form the basis for a modern synthesis and, in the broadest terms, dictate the framework within which the past and present distributions of organisms must be interpreted. Any scientific dis cipline must seek tests of its conclusions from data outside of its own confines.

South American ecosystems suffered one of the greatest biogeographical events, after the establishment of the Panamian land bridge, called the “Great American Biotic Interchange” (GABI). This refers to the exchange, in several phases, of land mammals between the Americas; this event started during the late Miocene with the appearance of the Holartic Procyonidae (Huayquerian Age) in South America and continues today. The major phases of mammalian dispersal occurred from the Latest Pliocene (Marplatan Age) to the Late Pleistocene (Lujanian Age). The most important and richest localities of Late Miocene-Holocene fossil vertebrates of South America are those of the Pampean region of Argentina. There are also several Late Miocene and Pliocene localities in western Argentina and Bolivia. Other important fossils have been collected in localities of Pleistocene age outside Argentina: Tarija (Bolivia), karstic caves of Lagoa Santa and the recently explored caves of Tocantins (Brasil), Talara (Perú), La Carolina (Ecuador), Muaco (Venezuela), and Cueva del Milodon (Chile), among others. The book discusses basic information for interpreting the GABI such as taxonomic composition (incorporating the latest revisions) at classical and new localities for each stage addressing climate, environments, and time boundaries for each stage. It includes the chronology and dynamics of the GABI, the integration of South American mammalian faunas through time, the Quaternary mammalian extinctions and the composition of recent mammalian fauna of the continent.

“An enjoyable read that provides a substantial amount of detail on the biology, ecology, and distribution of these fantastic animals . . . Highly recommended.” —Choice More than 10,000 years ago spectacularly large mammals roamed the pampas and jungles of South America. This book tells the story of these great beasts during and just after the Pleistocene, the geological epoch marked by the great ice ages. Megafauna describes the history and way of life of these animals, their comings and goings, and what befell them at the beginning of the modern era and the arrival of humans. It places these giants within the context of the other mammals then alive, describing their paleobiology—how they walked; how much they weighed; their diets, behavior, biomechanics; and the interactions among them and with their environment. It also tells the stories of the scientists who contributed to our discovery and knowledge of these transcendent creatures and the environment they inhabited. The episode known as the Great American Biotic Interchange, perhaps the most important of all natural history “experiments,” is also an important theme of the book, tracing the biotic events of both North and South America that led to the fauna and the ecosystems discussed in this book. “Collectively, this book brings attention to the discovery and natural history of ancient beasts in South America while providing a broader temporal and geographic background that allows readers to understand their evolution and potential immigration to South America.” —Quarterly Review of Biology “An excellent volume . . . This book is likely to facilitate progress in the understanding of fossil mammals from the Americas.” —Priscum

This volume combines 10 years of accomplished research at the Pilauco site. The studies are focused on a variety of scientific areas including geological, sedimentological, geomorphological and paleobotanical topics, as well as paleontology of vertebrata and invertebrata, micropaleontology, archaeology, biochemistry, taxonomy, taphonomy, astrophysics and the development of some particular touristic aspects. In 18 chapters a variety of authors describe the excavation and investigation of this unique location. The book presents Pilauco as an example for the natural laboratory which can be found in South America, a testing ground for many of the hypotheses regarding migrations of animals and humans. In this context the study of topics, such as the paleozoography, the role of megafauna species for the architecture of the forests, the animal extinctions or the early human settlements, is extremely important on a global scale. The Pilauco site features paleontological and archaeological evidences and is contemporaneous with the Monte Verde site (~ 15,000 cal. yr AP). It is located 100 km north from Monte Verde and lies within the Intermediate Depression in northwestern Chilean Patagonia. It was discovered by chance in 1986 and has been excavated and investigated since 2007.

This book takes a non-technical approach in covering the evolution of South American mammalian fauna throughout geological history, and discusses how South America has changed due to mammalian invasions. Unlike other works on the subject, this book attempts to answer several crucial questions that often go unmentioned together in one cohesive monograph. What was the fauna like before the American interchange? What were the origins of the now-extinct groups when northern species arrived and out-competed them? How did the modern mammalian fauna come into being with such disparate animal groups? This information is given from a historical perspective throughout the book's 15 chapters, and is presented in an easily graspable fashion by mostly avoiding technical language. The book is written for academics, scientists and scholars engaged in paleontology, zoology and evolutionary biology, but may also appeal to a larger audience of general readers interested in mammalian evolution. The book begins with an introduction, describing the tools necessary to interpret the evolutionary history of South American mammals in geological terms and some of the early people who helped found South American mammalian paleontology. Chapter 2 describes the Mesozoic first mammals of Gondwana and what we are learning about them, dominant before the K/T extinction event. Then chapters 3 through 8 cover the Cenozoic, or "Age of Mammals", highlighting the major mammalian groups of South America that replaced the earlier mammals of Gondwana. These groups include the marsupials, native ungulates, the xenarthrans (armadillos, anteaters, sloths), the caviomorphs (rodents), and the platyrrhine monkeys. Chapters 9 and 10 address the Antarctic La Meseta fossils and the Colombian La Venta fossil faunal assemblages. Chapter 11 discusses the neotropical mammals that invaded the Caribbean Islands, and illustrates the influence South America has had on adjacent faunas. Chapter 12 describes the origin of the Amazon River and the role it has played in the evolution of the mammals and other flora and fauna. Chapter 13 tells the story of the Great American Biotic Interchange (GABI), and chapter 14 follows this up with a discussion of the Pleistocene mammal communities and their eventual extinction. Chapter 15 concludes the text by discussing the modern mammals of South America, and how despite the extensive Pleistocene extinctions there is still a lot of mammalian diversity in South America.

This book summarizes the evolution of carnivorous mammals in the Cenozoic of South America. It presents paleontological information on the two main mammalian carnivorous groups in South America; Metatheria and Eutheria. The topics include the origin, systematics, phylogeny, paleoecology and evolution of the Sparassodonta and Carnivora. The book is based on a wide variety of published sources from the last few decades.

The fish faunas of continental South and Central America constitute one of the greatest concentrations of aquatic diversity on Earth, consisting of about 10 percent of all living vertebrate species. Historical Biogeography of Neotropical Freshwater Fishes explores the evolutionary origins of this unique ecosystem. The chapters address central themes in the study of tropical biodiversity: why is the Amazon basin home to so many distinct evolutionary lineages? What roles do ecological specialization, speciation, and extinction play in the formation of regional assemblages? How do dispersal barriers contribute to isolation and diversification? Focusing on whole faunas rather than individual taxonomic groups, this volume shows that the area’s high regional diversity is not the result of recent diversification in lowland tropical rainforests. Rather, it is the product of species accumulating over tens of millions of years and across a continental arena.