The early history of the Sciuridae is not well known, squirrels being generally poorly represented in the Tertiary fossil record. A nearly complete skeleton, recently discovered in early Oligocene deposits of Wyoming, represents what may be the oldest fossil squirrel known. For the first time, this early squirrel can be compared fully with its extant relatives. The specimen, assigned to Protosciurus jeffersoni, retains the primitive protrogomorphous zygomasseteric structure, as in other known Protosciurus, but the masseteric fossa of the mandible is farther forward than in most nonsciurid protrogomorphs. The auditory region of the skull has derived squirrel characters, but it is in the postcranial skeleton where similarities to extant squirrels are most apparent. Except for minor differences in joint construction, the skeleton is strikingly similar to that of Sciurus niger, the living fox squirrel. It differs from extant ground squirrels in the more gracile proportions of its long bones and asymmetry of foot construction. This early member of the squirrel family was clearly an arboreal squirrel, with morphology, and presumably habits, very similar to those of extant Sciurinae.

A valuable resource for the latest research on rodents, highlighting links across palaeontology, developmental biology, functional morphology, phylogenetics and biomechanics.

The order Rodentia is the most abundant and successful group of mammals, and it has been a focal point of attention for compar ative and evolutionary biologists for many years. In addition, rodents are the most commonly used experimental mammals for bio medical research, and they have played a central role in investi gations of the genetic and molecular mechanisms of speciation in mammals. During recent decades, a tremendous amount of new data from various aspects of the biology of living and fossil rodents has been accumulated by specialists from different disciplines, ranging from molecular biology to paleontology. Paradoxically, our understanding of the possible evolutionary relationships among different rodent families, as well as the possible affinities of rodents with other eutherian mammals, has not kept pace with this information "explosion. " This abundance of new biological data has not been incorporated into a broad synthesis of rodent phylo geny, in part because of the difficulty for any single student of rodent evolution to evaluate the phylogenetic significance of new findings from such diverse disciplines as paleontology, embryology, comparative anatomy, molecular biology, and cytogenetics. The origin and subsequent radiation of the order Rodentia were based primarily on the acquisition of a key character complex: specializations of the incisors, cheek teeth, and associated mus culoskeletal features of the jaws and skull for gnawing and chewing.

Nearly half of the known species of mammals alive today (more than 1600) are rodents or "gnawing mammals" (Nowak and Paradiso, 1983). The diversity of rodents is greater than that of any other order of mammals. Thus, it is not surprising that the fossil record of this order is extensive and fossil material of rodents from the Tertiary is known from all continents except Antarctica and Australia. The purpose of this book is to compile the published knowledge on fossil rodents from North America and present it in a way that is accessible to paleontologists and mammalogists interested in evolutionary studies of ro dents. The literature on fossil rodents is widely scattered between journals on paleontology and mammalogy and in-house publications of museums and universities. Currently, there is no single source that offers ready access to the literature on a specific family of rodents and its fossil history. This work is presented as a reference text that can be useful to specialists in rodents (fossil or recent) as weIl as mammalian paleontologists working on whole faunas. Because the diversity of rodents in the world is essentially limitless, any monograph that included all fossil rodents would similarly be limitless. Hence, this book is limited to the re cord of Tertiary rodents of North America. The several species of South American (caviomorph) rodents that invaded North America near the end of the Tertiary are also not included in this text.

Publisher description

The case history approach has an impressive record of success in a variety of disciplines. Collections of case histories, casebooks, are now widely used in all sorts of specialties other than in their familiar appli cation to law and medicine. The case method had its formal beginning at Harvard in 1871 when Christopher Lagdell developed it as a means of teaching. It was so successful in teaching law that it was soon adopted in medical education, and the collection of cases provided the raw material for research on various diseases. Subsequently, the case history approach spread to such varied fields as business, psychology, management, and economics, and there are over 100 books in print that use this approach. The idea for a series of Casehooks in Earth Science grew from my experience in organizing and editing a collection of examples of one variety of sedimentary deposits. The prqject began as an effort to bring some order to a large number of descriptions of these deposits that were so varied in presentation and terminology that even specialists found them difficult to compare and analyze. Thus, from the beginning, it was evident that something more than a simple collection of papers was needed. Accordingly, the nearly fifty contributors worked together with George de Vries Klein and me to establish a standard format for presenting the case histories.

Mammals of Africa (MoA) is a series of six volumes which describes, in detail, every currently recognized species of African land mammal. This is the first time that such extensive coverage has ever been attempted, and the volumes incorporate the very latest information and detailed discussion of the morphology, distribution, biology and evolution (including reference to fossil and molecular data) of Africa's mammals. With more than 1,160 species and 16-18 orders, Africa has the greatest diversity and abundance of mammals in the world. The reasons for this and the mechanisms behind their evolution are given special attention in the series. Each volume follows the same format, with detailed profiles of every species and higher taxa. The series includes hundreds of colour illustrations and pencil drawings by Jonathan Kingdon highlighting the morphology and behaviour of the species concerned, as well as line drawings of skulls and jaws by Jonathan Kingdon and Meredith Happold. Every species also includes a detailed distribution map. Edited by Jonathan Kingdon, David Happold, Tom Butynski, Mike Hoffmann, Meredith Happold and Jan Kalina, and written by more than 350 authors, all experts in their fields, Mammals of Africa is as comprehensive a compendium of current knowledge as is possible. Extensive references alert readers to more detailed information. Volume III, edited by David Happold, has profiles of 395 species of rodents, comprising the squirrels, dormice, jerboas, blind mole-rats, African root-rats, pouched rats and mice, Swamp Mouse, climbing mice, fat mice, White-tailed Rat, rock mice, voles, Maned Rat, spiny mice, brush-furred mice, gerbils, jirds, taterils, African Forest Mouse, rats and mice, vlei rats, whistling rats, anomalures, springhares, gundis, African mole-rats, porcupines, Noki (Dassie Rat), cane rats and Coypu. The volume concludes with 13 species of hares and rabbits.