Book Contents And Format
We see photo above have endeavored to make this book as comprehensive as possible, within practical limitations. Of the 15 chapters that follow, four chapters 1-3 and 15 are of a general nature and apply to the full spectrum of early mammals, whereas the remaining 11 chapters deal with the anatomy, paleobiology, and systematics of the particular groups of mammals known from the Mesozoic, extinct and extant. In chapter 1, we provide some general background on mammals within the context of...
AFRICA Pjj
The most significant Late Cretaceous mammals recovered from the African region are from Madagascar figure 2.6 . We include Madagascar in the section on the modern African region, but point out that it actually maintained some limited contact with India during the early part of the Late Cretaceous epoch. A diverse vertebrate fauna has been recovered from the Anembalema Member of the Maeverano Formation, near the village of Berivotra in the Mahajanga Basin, northwestern Madagascar see summary by...
North America
Several previously mentioned occurrences of possible mammals in the Late Triassic of North America specifi-cally North Carolina and Texas Clemens et al., 1979 are now thought more likely to represent therapsids, as noted earlier Sues, 2001 . In the meantime, however, more secure records of mammals from both the Late Triassic and Early Jurassic have been reported from the continent. Adelobasileus cromptoni see Lucas and Hunt, 1990 is known by the posterior part of a skull from Home Creek, Crosby...
India
A possible mammal, Gondwanadon tapani, has been described from near the village of Tiki, Madhya Pradesh figure 2.5, table 2.3 . Gondwanadon is based on an incomplete, two-rooted, molariform tooth, said to be similar to figure 2.5. Mesozoic mammals of India. Asterisks, Late Triassic-Early Jurassic localities 1-4 diamond, Cretaceous localities 5, 6 . Localities or local faunas 1, Tiki Tiki Formation Carnian, Madhya Pradesh 2, Paikasigudem 3, Manganpalli 4, Yamanapalli Kota Formation Early...
Acknowledgments
We began work on this book on Mesozoic mammals at the beginning of 1999. With support from our colleagues Donald R. Prothero and Hans-Dieter Sues, we signed the contract with Columbia University Press in April 1999. During our five years of work on this book, we greatly benefited from the help and advice of numerous colleagues and friends, who generously offered us enormous assistance in various ways. Primary among them cited in alphabetic order are Alexander O. Averianov and William A....
Eastern Europe
Only one region in Eastern Europe has thus far yielded mammals of Late Cretaceous age, the Halieg Basin, Romania figure 2.16, table 2.17 . A useful account of the geologic setting and microvertebrate fauna in general is given by Grigorescu et al. 1999 . As noted, Europe assumed the form of an archipelago during parts of the Late Cretaceous. Theropods known from Transylvania are generally small, and this seems to be true of other dinosaurs as well, suggesting that the region was, indeed, insular...
ASIA Bel
The vast area of Russia and adjacent countries formerly included in the Soviet Union was long a complete blank for Cretaceous mammals. A single specimen of a Late Cretaceous eutherian from Kazakhstan was described by Bazhanov 1972 , but it remained for Lev A. Nessov to more fully exploit middle Asia for fossil mammals in a series of expeditions beginning in 1978. Nessov must be given the greatest credit for his remarkable contributions to knowledge of early mammals. His achievements are all the...
Successive Diversifications Of Mesozoic Mammals
Most Mesozoic mammal species are represented only by teeth and incomplete jaws. Inadequate as they are for a comprehensive understanding of whole organisms, teeth and jaws nonetheless provide useful information about the taxonomic richness and diverse feeding adaptations of early mammals. Their records show several major episodes of diversification figure 1.1 . The earliest diversification took place among stem mammals during the Late Triassic to Early Jurassic. From this initial burst of...
Continental Europe
for example, those of the type Lance Formation, eastern Wyoming Clemens, 1963b . We find it neither practical nor desirable to list all such occurrences independently, and instead use composite local faunas admittedly arbitrary in some cases for such assemblages. Faunal lists are grouped together by age and region individual sites or local faunas are keyed to corresponding maps by numbers. Late Triassic through Early Jurassic mammal sites of Western Europe table 2.1, figure 2.2 fall into two...
SOUTH AMERICA Nlx
Mammals of Late Cretaceous age are known from scattered sites in Brazil, Argentina, Bolivia, and Peru figure 2.7, table 2.21 . Collectively, these occurrences rank the Late Cretaceous mammal record from the South American continent as far superior to that of all other Gond-wanan landmasses combined. Yet we still lack sufficient evidence for a reasoned interpretation of mammalian bio-geography and faunal dynamics, both within South America and among the Gondwanan continents. It is especially...
WESTERN EUROPE Abo
Late Cretaceous mammals of Western Europe are now known from France, Spain, and Portugal table 2.16 . Most sites or occurrences are listed as being of Campanian-Maastrichtian or Maastrichtian age, with the exception of Champ-Garimond, France, which is believed to be Cam-panian. As summarized by Le Loeff 1991 , Europe during the Late Cretaceous was an archipelago. Of the four major noninundated areas, Late Cretaceous mammals are known from the Ibero-Armorican and Transylvanian landmasses. As a...
Info Chr
Sigogneau-Russell and Hahn, 1994 . This unit spans the Upper Triassic, but mammalian fossils are restricted to its upper part. Thus far, specimens consist only of isolated teeth or parts thereof. Given the great antiquity of these remains, the affinities of the taxa they represent are sometimes debatable. Tricuspes, for example, occurs at several sites in the Keuper. It may be a mammal Clemens, 1980a, 1986 , but is more generally considered a cynodont Godefroit and Sigogneau-Russell, 1995 , and...
North America 1
North America's Late Jurassic mammal assemblage table 2.8 is the most diverse of this age in the world. All the specimens come from one unit, the Morrison Formation, and the vast majority of published specimens come from one site at Como Bluff, Wyoming Simpson, 1926c . Notwithstanding some reports to the contrary e.g., Bil-bey, 1998 , an overwhelming body of radiometric, paleo-magnetic, palynological, and other data indicate the Morrison Formation to be an exclusively Upper Jurassic unit,...
Greenland
A hard-won vertebrate fauna, including mammals, has been collected by Farish A. Jenkins, Jr., and associates from Upper Triassic rocks of Jameson Land, northeastern Greenland, at more than 71 N latitude figure 2.8 . Thus far, the assemblage includes dinosaurs and other archo-saurs, turtles, labyrinthodonts, and fishes, in addition to four mammals. The fauna is very similar to that of the Norian part of the Keuper in Western Europe, sharing such taxa as Gerrothorax, Cyclotosaurus, Proganochelys,...
Australia
An island continent with a highly endemic biota sharing certain elements with other southern continents, Australia has long fascinated students of evolution and biogeogra-phy. Until recently, though, no mammalian fossils older than Miocene were known from this important landmass down under. Discoveries in the Early Cretaceous of Australia table 2.12 are now beginning to shed light on the antiquity of mammals there and are raising fundamental new questions on the origin and relationships of some...
Multituberculates From The Woodbine
Bona fide Early Cretaceous mammals are known from four regions and stratigraphic units in North America the Trinity Group, Texas and Oklahoma figure 2.14 the Cloverly Formation, Wyoming and Montana the Kelvin Formation, Utah figure 2.10 and the Arundel Clay, Maryland figure 2.15 . A fifth, the Cedar Mountain Formation, Utah figure 2.10 , straddles Albian-Cenomanian time Early-Late Cretaceous and is arbitrarily discussed under this heading as well. The Trinity Group in north-central Texas...
Paradigm Shifts In Mesozoic Mammal Evolutionary Studies
A significant conceptual advance from recent studies of early mammals is the understanding that the greatest tax-onomic diversification and morphological divergence tends to appear in the earlier periods of each major clade Rowe, 1993 Cifelli, 2001 Luo et al., 2002 . The most significant diversification of Mesozoic mammals occurred long before the splits of modern lineages of monotremes, marsupials, and placentals. It is near the root of the mammal tree that many basal branches split off, so as...
Premammalian Synapsids
The synapsid lineage that includes mammals split from other amniote vertebrates over 300 Ma ago, during the Late Carboniferous Pennsylvanian in the Paleozoic. Synapsids are characterized by the presence of a lower temporal fen-estra in the skull, among other apomorphies. Their stem taxa, or pelycosaurs, thrived in the Late Pennsylvanian through the Early Permian Kemp, 1982 Carroll, 1988 Hopson, 1994 . Therapsids, a derived subgroup of synapsids, are characterized by enlargement of the temporal...
Major Discoveries Of The Past Two Decades
The first Mesozoic mammal was discovered in 1764, although its significance was not appreciated until almost a century later Owen, 1871 . The first scientifically documented Mesozoic mammal, now known as Phasco-lotherium bucklandi, was discovered in 1812 in a masonry quarry in the Middle Jurassic Stonesfield slates near Head-ington, England. The fossil was later deposited at Oxford University, where it was recognized by Baron Georges Cuvier to be mammalian in 1818, announced as such by William...