Living Dinosaurs: The Evolutionary History of Modern Birds

that smacks of “science by consensus,” embodied by statements such as those by Henry Gee, a senior editor of the journal Nature, that “birds are dinosaurs: the debate is over,” and Richard Prum’s assertion that “it is time to abandon debate on the theropod origin of birds” (see p. ). Rather, Feduccia urges for the application of the traditional approach of proposing and testing viable alternative hypotheses that are indicated by these emerging data, rather than shoe-horning them into support of the existing hypothesis. In Feathered Dragons, Feduccia provides the reader with a variety of compelling, but often ignored, data that are at odds with a derived theropod ancestry for birds. Among the examples of contradictory evidence that he showcases is the case of non-homology of the manual digits in theropods and birds—that although the three digits on the hands of theropods and birds often bear remarkable anatomical similarities, multiple developmental studies have indicated that the avian hand comprises digits , , and  whereas the generalized theropod hand is broadly acknowledged to be made up of digits , , and . To account for this discrepancy, bird–dino supporters have invoked a genetic frame-shift mutation that altered the identity of the digits, an unprecedented event in amniotes. In another example of a report that strains credulity, Feduccia examines the claims of preserved soft tissues from a -millionyear-old T. rex fossil. Several papers published in high-profile journals claimed to have recovered tissues including collagen, blood vessels, and even red blood cells from the femur of a tyrannosaurid, and to have extracted DNA that resembled that of birds—extraordinary assertions that made headlines. As Feduccia points out, follow-up analyses that cast serious doubts on these claims received little fanfare. Feduccia also discusses the bombshell news from , when the first of many “feathered theropods” began to emerge from China. These reports shook the scientific world and made headlines across the globe. These fossils were heralded as the final “nail in the coffin” for doubters of a close theropod–bird linkage. Feduccia provides a comprehensive treatment of the literature on the subject and shows that although many of the fossils are indeed feathered (and are also birds), a number of key specimens of more basal theropods described as “feathered” or “protofeathered” (i.e., possessing supposed simple filamentous integumentary fuzz) are in reality more likely to represent unusual preservation of dermal (within the skin) collagen fibers. These are just a few of the pieces of possibly dubious evidence that have been used to verify a dinosaurian ancestry for birds. Feduccia argues that these suspect studies should, at the very least, provoke a reexamination of the questions at hand. Additionally, he provides an excellent treatment of the diverse fossils of enantiornithine (archaic “opposite” birds) and basal members of ornithiurine (modern) bird lineages from northeast China. He also evaluates a number of the curious, small dromaeosaurid microraptors, Velociraptor-like animals with arboreal adaptations (which included a perching foot and feathers forming wing surfaces on both foreand hindlimbs). What to do with this avalanche of data? Feduccia urges that it be reanalyzed without a predetermined conclusion in mind. That this controversy has become so bitterly fought is a bit of a wonder, in that both sides agree that birds and dinosaurs are closely related—the issue balances on when and where birds diverged from within the archosaurs. Thus, perhaps the most surprising suggestion Feduccia offers, and one that deserves a Living Dinosaurs: The Evolutionary History of Modern Birds. —Gareth Dyke and Gary Kaiser, Editors. . WileyBlackwell, Chichester, United Kingdom. xv +  pp.,  color plates,  text figures,  tables,  appendices. ISBN . eBook . Cloth, $. . —This volume comprises  invited chapters authored by  contributors. As noted by the editors, the chapters represent “seemingly unrelated approaches to the study of avian evolution. ” The stated purpose is to “help bridge a gap that has developed between those who study birds as fossils and those who study the living animals. ” Once one gets beyond the inexplicable title and the first three chapters, to which I will return, one finds several interesting and thought-provoking chapters that work toward the editors’ goal. Others are less successful. The book is divided into four parts of unequal depth, with each chapter comprising a review of its topic. In this sense it is a useful tool, in that one can find an updated list of references for each topic, although the lists are often as notable for what is left out as for what is included. The three themes that I found most interesting are the reviews of specific avian groups, the evolution of certain avian traits, and the discussions of current methodologies for understanding avian evolution. Of the first, a review of the giant, presumably marine “pseudo-toothed,” or “false-toothed,” odontopterygiform birds by E. Bourdon and a review of penguins by D. Ksepka and T. Ando are highlights. Focusing on a cladistic analysis instead of possible life-history traits and functional morphology, the chapter by H. Alvarenga et al. on phorusrhacids, the “terror birds” of South America, is disappointing. Finally, F. Barker presents hypotheses of phylogeny and diversification of passerines, with a heavy emphasis on molecular models. much longer look from anyone interested in these questions, is that data drawn from the myriad of new fossils could actually be turning conventional wisdom on its head (literally)—that is, the very birdlike dinosaurs such as the iconic ‘raptors of Jurassic Park (e.g., Velociraptor and its relatives), the enigmatic troodontids, and the bizarre beaked oviraptorosaurs—long considered to be among the more derived theropods—are, in fact, members of an extensive adaptive radiation of volant and secondarily flightless birds! Those who have followed Feduccia’s work over the years will recognize that this conclusion is a major shift in his views, and that his ability to deal with the new evidence in such an unbiased and creative manner is the mark of a uniquely sharp and innovative scientific mind. Whether one ultimately agrees with Feduccia or not, Feathered Dragons: Hidden Birds of China is a “must read” for anyone interested in these questions and will prod its readers to rethink received wisdom on the subject of the evolution of birds. —Nicholas Geist, Department of Biology, Sonoma State University,  East Cotati Avenue, Rohnert Park California , USA. E-mail: nick. geist@sonoma.edu