Since Alfred Russel Wallace's (1876) treatise on the distribution of animals on the planet, the biogeography of mammals of the Neotropics has inspired hypotheses and fueled investigations relating to isolation, diversification, endemism, faunal turnover, and extinction. These issues were synthesized in several books published about three decades ago, including Splendid Isolation, George Gaylord Simpson's (1980) perspective on the formation of the highly diverse and endemic South American fauna. Similarly, Bones, Clones, and Biomes: The History and Geography of Recent Neotropical Mammals is an ambitious attempt to provide a new synthesis of “regional and historical features of the modern Neotropical mammalian fauna.” Stemming from a symposium at the 10th International Mammalogical Conference, in Mendoza, Argentina, in 2009, this book significantly expands and updates previous treatments of Neotropical mammalogy. There is also a hopeful departure from past volumes in its significant percentage (more than 75 percent) of Latin American authors, which demonstrates the tremendous talent and potential of local investigators in the Neotropics to push the limits of our knowledge of this incomparable fauna.
Editors Bruce D. Patterson (MacArthur curator of mammals at the Field Museum of Natural History) and Leonora P. Costa (associate professor in the Biological Sciences Department at the Universidade Federal do Espírito Santo, in Vitória, Brazil) assembled 32 additional authors with wide expertise on the biogeography of Neotropical mammals to focus on a central question: How did changing climates and landscapes, intercontinental connections, and newly evolved lineages interact to populate Central and South America and the Antilles with almost 30 percent of the world's living mammals? After a brief introductory chapter to the entire volume by the editors, the book is divided into two major sections: “The Geological Setting” and “Regional Patterns,” each with an overview chapter. The first section of seven chapters sets the stage for interpreting contemporary patterns of regional endemism, diversity, and biogeography—which are further discussed in the final nine chapters of the second section. There is considerable overlap between these two sections, which helps to integrate the work of the contributed material. For example, a molecular genetic study of carnivores is nicely juxtaposed with a chapter on their fossil history in the first section, and in the second section, most of the regional coverage of contemporary biogeography discusses perspectives emanating from both the fossil record and molecular studies.
Bones, Clones, and Biomes draws on a slew of new sites and fossil discoveries and insights gained from molecular genetics that have altered our understanding of the movement of organisms and the timing of major events that shaped the dynamic biogeography of the region, including the diversification and turnover of the Neotropical fauna. New paleontological perspectives extending to over 250 million years ago (mya) explore endemism, continental interchange, waif arrival, body-size evolution, and Pleistocene megafaunal extinctions. On a global scale, the extinction spasm was most severe in South America, with the loss of two diverse orders of endemic herbivores (notoungulates and litopterns) and four families of xenarthrans. The implications of modern ecosystems (from just 10,000 years ago) having this degree of loss of major faunal components have yet to be thoroughly examined in the Neotropics.
Of note is the introduction of FABI, the First American Biotic Interchange (about 65 mya), an event that complements the much-debated GABI (Great American Biotic Interchange). The initiation of GABI was traditionally thought to occur 3 mya, with the final closure of the Isthmus of Panama, but new revelations from the fossil record indicate the movement of sloths northward to Florida and California as early as 9 mya, pushing the origin of this dynamic exchange and the potential for faunal turnover much further back in time.
Bones, Clones, and Biomes also provides regional knowledge of mammalian biogeography—excluding aquatic and marine mammals—of most of the major biomes of South America. The Chaco (between the Paraguay River and the Andean mountains) and the Valdivian Forest (on the southwestern coast) are missing. Importantly, this synthesis extends to the biomes of Central America and the Antilles. Although some of the regional accounts are a bit uneven in scope, most include traditional taxonomy-based summaries of mammalian diversity, endemism, and biogeography, in addition to molecular phylogenetic and phylogeographic analyses of the origin, expansion, and demographic history of exemplar taxa. The tables and illustrations are of reasonable quality, and several of these chapters include useful species lists as appendices. This excellent volume should therefore generate wide interest as an example of how to integrate science research across disciplines ranging from molecular genetics to paleontology as a means of exploring the dynamic history of a region. As both a synthesis of our current understanding and a user-friendly reference work (both taxonomic and subject indices are included), Bones, Clones, and Biomes will find broad use.
A common theme throughout much of the book is that limited sampling remains a key impediment to both paleontological and neontological studies in the Neotropics. Much of what we know is still based on relatively few localities and taxa. If the detailed fossil record available from Patagonia is as distinct from that of the remainder of the Neotropics in the past as their faunas are today, the southern fossil sites used by earlier paelontologists may continue to offer limited insight into paleomammalogy throughout this immense biogeographic realm. Toward that end, Bones, Clones, and Biomes summarizes a series of newer discoveries in Chile, Bolivia, and Colombia, among other places.
The urgency of additional fieldwork in the Neotropics cannot be overstated, particularly given the rapid loss of habitat in several of these regional biomes. Primary forest destruction in the Amazon Basin continues in a futile effort to slake our thirst for biofuels, and biomes such as the Atlantic Forest have effectively vanished. One wonders what a synthesis on Neotropical mammalian biogeography will entail in 30 years.
- GG. Simpson 1980. Splendid Isolation: The Curious History of South American Mammals. Yale University Press. Google Scholar
- AR. Wallace 1876. The Geographical Distribution of Animals: With a Study of the Relations of Living and Extinct Faunas as Elucidating the Past Changes of the Earth's Surface. Macmillan. Google Scholar