Organization Of The Volume

Chapter 2 provides an overview of mammalian skeletal anatomy and the principal features of the skeleton and dentition that are used to interpret diet, locomotion, and other aspects of behavior in fossil mammals. A review of the origin of mammals follows in Chapter 3, and a synopsis of mammalian evolution during the Mesozoic in Chapter 4, as the background to the Early Cenozoic radiation that is the principal focus of the book. The Multituberculata, a Meso-zoic clade that survived into the Early Cenozoic and was a significant constituent of many Paleocene faunas, is covered in the latter chapter. In Chapter 5 the fossil record of Meta-theria from the Cretaceous through the Eocene is presented. Basal eutherians of the Cretaceous, the primitive antecedents of the Cenozoic placental radiation, are highlighted in Chapter 6.

Chapters 7 through 15 summarize the Paleocene-Eocene fossil record of eutherian mammals. In some cases pertinent early Oligocene groups are discussed as well. Chapters generally group taxa that are, or have been, thought to be monophyletic; but for some taxa the evidence for mono-phyly is weak at best, and the association is really more one of convenience. Cladograms and classification tables are included in Chapters 4 through 15 to help readers place tax-onomic groups in phylogenetic context. In the tables a dagger symbol (f) is used to indicate extinct taxa, and families and genera known from the Paleocene or Eocene are shown in boldface. Unless otherwise indicated, most classifications used in the book are modified after McKenna and Bell (1997, 2002). All Paleocene-Eocene higher taxa are listed, but complete listings of all later Cenozoic and Recent taxa are omitted for some of the most diverse orders.

Chapter 7 covers the primitive cimolestan "insectivores" as well as several clades that have been associated with them or are thought to be their descendants, including didymo-conids, pantolestans, apatotheres, taeniodonts, tillodonts, and pantodonts. In Chapter 8 the creodonts and carnivorans are reviewed. Insectivora, including leptictids and lipoty-phlans are the subject of Chapter 9. The early fossil record of the Archonta, including bats, dermopterans, tree shrews, and primates, is detailed in Chapter 10. Chapter 11 concerns the xenarthrans, pangolins, and palaeanodonts—mammals loosely grouped as "edentates," although there is little convincing evidence for relationship of the xenarthrans to the others. Under the heading of archaic ungulates, the subject of Chapter 12, are grouped condylarths as well as an assortment of other primitive ungulates, including uintatheres, arctostylopids, and the extinct South American ungulates (litopterns, notoungulates, pyrotheres, astrapotheres, and xenungulates). This grouping, too, is one of convenience and does not imply any special relationship. Chapter 13 describes the Altungulata, which comprises perissodactyls, hyracoids, and tethytheres (sirenians, proboscideans, and arsinoitheres). Cetacea, archaic mesonychians, and artio-dactyls are discussed in Chapter 14. Chapter 15 summarizes the fossil record of Anagalida: the rodents, lagomorphs, and possible relatives, including elephant shrews and several fossil clades. The final chapter provides a retrospective on mammalian evolution during the beginning of the Age of Mammals.

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