The Beginning of the Age of Dinosaurs

Book excerpt: Around 210 million years ago, life on Earth experienced sweeping changes. Many archaic reptiles and mammalian predecessors became extinct and were replaced by dinosaurs, pterosaurs, crocodiles, turtles, mammals, and essentially all of the major modern vertebrate groups except the birds. This period of change, which took place over a period of approximately five to ten million years, ushered in the beginning of the 'Age of Dinosaurs,' a period that lasted 160 million years to the end of the Cretaceous 65 million years ago. In the past decade, paleontologists have come to know a great deal more about this crucial interval of time. New discoveries, ideas, and insights from scientists in many related- disciplines have created new paradigms about the beginning of the 'Age of Dinosaurs.' What were the animals that preceded the dinosaurs like? How did the dinosaurs originate, and what do we know of their early history? Was their ascent tied to evolutionary innovations, global climatic and ecological changes, or just chance factors? How do paleontologists decide about the evidence preserved in the fossil record, and what areas now require major thought and reevaluation? In this book, 31 specialists in the paleontology of this era consider these and other questions related to Late Triassic and Early Jurassic times - the beginning of the 'Age of Dinosaurs,' its fauna, flora, climate, stratigraphic relationships, and major evolutionary changes. The book is divided into sections on background, Late Triassic taxa and faunas, changes across the boundary, Early Jurassic taxa and faunas, and major macroevolutionary patterns. This comprehensive volume is richly illustrated and is intended for students and professionals in the areas of paleontology, evolutionary biology, geology, and vertebrate zoology. Introductory and summary chapters are provided to acquaint the non-specialist with the issues and the setting of this interval of time in which the ancestral components of the modem fauna, as well as the Dinosauria, first appeared to rule the Earth.