Flighty tales from the past

In terms of public awareness, Archaeopteryx is probably one of the most widely recognised fossil animals. Part reptile, part bird, it is a unique snapshot of evolution in action - a missing link between two major groups of animals. Preserved in fine-grained limestone, its skeleton closely resembles that of a small meat-eating dinosaur, and yet it had feathers too. The imprints of wing and tail feathers, structurally identical to those of modern birds, are stamped clearly in the rock around the bones:a 147 million-year-old stamp of authenticity that Archaeopteryx had feathers and could fly. So was it a bird or was it a dinosaur? The answer, accepted by most palaeontologists, is that it was both.

Archaeopteryx , the origin of birds and bird flight has generated a huge literature of primary research papers and a steady stream of reviews and books aimed at both the specialist and lay reader. These two books overlap rather less in content than their titles suggest and approach the topic from very different perspectives.

Pat Shipman, an anthropologist, has written a personal synthesis derived from the literature and conversations with key players in the field. An unfortunate starting note is the dust cover, which has an eye-catching picture of a flying fossil: but it is not Archaeopteryx as described, it is a pterosaur! A publisher's faux pas , one presumes, and soon corrected as Shipman takes readers on an extended tour of the specimens of Archaeopteryx , a feather and seven skeletons. She details the early history of the London and Berlin specimens, setting the science of Richard Owen and Thomas Henry Huxley against contemporary Victorian society. Huxley spotted the relationship between Archaeopteryx and the few dinosaurs known in 1868, more than a century before it was widely accepted as the most parsimonious explanation for the origin of birds.

Moving to the more recent Archaeopteryx discoveries, Shipman uses quotations from the practitioners themselves, which brings the book alive. John Ostrom of Yale University, the inspiration of modern studies on the dinosaurian origin of birds, discovered in 1970 one of the seven Archaeopteryx specimens in the Teyler Museum in Haarlem, where it had lain since 1857 masquerading as a pterosaur. Ostrom's enthusiasm and excitement is evident in reading the story of his discovery. Throughout, the author reminds us of the dedication and tenacity of researchers in the field and highlights the personalities behind the science, warts and all.

In the mid-1980s, the London and Berlin specimens of Archaeopteryx, more specifically their feather impressions, were the subject of forgery allegations by a small group of physical scientists led by Fred Hoyle and Chandra Wickramasinghe. Inevitably, this bizarre episode has become part of the Archaeopteryx story. As one who was at the sharp end of that affair and one of the authors who wrote in defence of the London Archaeopteryx's reputation, I found Shipman's long, opinionated account less than wholly accurate and her holier-than-thou attitude irritating.

Shipman explores the principles of flight, its physics, mechanics and constraints in modern birds, bats and pterosaurs and the early history of aviation from hot-air balloons onwards. She relates these principles to anatomy, physiology and biomechanics in her discussion of the continuing controversy concerning flight; did it originate from the trees down or the ground up? This involves a good deal of technical detail, but explanations and asides are sufficient to keep non-technical readers on track.

This is a very readable book. Shipman tackles a complex subject in an accessible and engaging manner, skilfully conveying her enthusiasm. However, it is hard to distinguish the author's input from the many reference sources. The reader is obliged to scrutinise the chapter notes at the end of the book for matching words and phrases. This may be the publisher's house style, but it detracts from the book's potential value as a scientific reference. Taking Wing is also likely to attract readers seeking a narrative account, rather than a textbook-style presentation, of the evolution of bird flight.

Lowell Dingus and Timothy Rowe's book is much broader in scope, setting the story of Archaeopteryx in the context of extinction events and dinosaur evolution. It is very much a two-part book. Part one examines the disappearance of those animals traditionally regarded as dinosaurs, of which Tyrannosaurus was one of the last to go. This thorough exposition presents all the evidence for asteroid impacts, volcanism, continental drift, sea level and climate change as explanations for the end-Cretaceous extinction event, and readers are invited to judge for themselves. Dingus reminds us of the fact that extinction hypotheses must account not only for the demise of most dinosaurs, but, significantly, for the survival of all the vertebrate groups that are still present today.

Part two deals with the evolutionary history of birds and their descent from the earliest land vertebrates. The text is a direct condensation of a popular course on dinosaur evolution given by Rowe at the University of Texas at Austin. He provides a lucid history and philosophy of science from which our modern cladistic views of the biological world have developed. The main dinosaur lineages are covered concisely, but readers should note that this book is not a general compendium of dinosaur facts and figures. Dinosaur genealogy is set into the larger themes of earth history, including more recent extinction events and the evolution of humans. Rowe clearly draws out concepts and topical issues in evolutionary biology as applied to the past and present history of dinosaurs - added value that distinguishes this book from the many others on the market.

Rowe then guides the reader from dinosaurs past to dinosaurs present. He chronicles the recent exciting discoveries of post- Archaeopteryx Mesozoic birds, and evolution and diversification through the past 65 million years. The last chapter documents the role of modern humans in the extinction of birds, a grim reminder that the fate of dinosaurs, which have survived for more than 150 million years, now rests in our hands. The book concludes with an unashamedly propagandist epilogue lamenting the budgetary cuts in the study of the natural history of our planet and the potential disastrous effects wrought by our own species on the natural world's diversity.

The Mistaken Extinction is almost three books in one: extinction, dinosaur phylogeny and a history of birds. There are other books that deal in much more detail with each of these single topics, but this one offers a concise, interesting and well-illustrated account of one of the most significant chapters in vertebrate evolution. It should appeal to students and to general readers and not least to anyone with an interest in birds.

Angela C. Milner is head of the fossil vertebrates and anthropology division, Natural History Museum, London.