The Origin and Evolution of Larval Forms

THE ORIGIN AND EVOLUTION OF LARVAL FORMS. Brian K. Hall and Marvalee H. Wake, eds. 1999. Academic Press, San Diego, California. ISBN 0-12-730935-7 425 p. $79.95 (hardbound).—This well-conceived and well-edited book offers much of interest to both herpetologists and ichthyologists, although it deals with larval biology of insects and marine invertebrates as well as vertebrates. I will focus on the chapters dealing with vertebrates. Several of these chapters represent integrative biology at its best, with discussions that cut across the fields of developmental biology, genetics, evolution, functional morphology, and ecology. It is an excellent reference for graduate students and investigators in these fields and for herpetologists and vertebrate biologists in general. I found much information that was useful in preparing lectures for both a graduate level herpetology course and an undergraduate vertebrate biology course. There is some overlap in content with the recently published book on tadpoles (McDiarmid and Altig, 1999), but Hall and Wake's book provides a much broader taxonomic and evolutionary perspective on larval biology, with considerably less detail on tadpoles.

Multiauthor volumes often suffer from a lack of synthesis, but this book is provided with an excellent introductory chapter by the editors, who give a historical overview of research on the larval biology of invertebrates and vertebrates, including development, evolution, and ecology. This chapter does a nice job of providing a conceptual framework for the rest of the book. The editors also provide a brief epilog at the end of the book that ties together the themes of the separate chapters and suggests productive avenues for future research. My only criticism is that the links between larval biology of invertebrates and vertebrates are not always clear, and I cannot help but think, from the perspective of a vertebrate biologist, that the book would have been even more successful if it had a more limited taxonomic focus.

Several chapters will be of great interest to herpetologists. James Hanken's chapter on “Larvae in Amphibian Development and Evolution” is a high point of the book. It provides a masterful synthesis of amphibian larval development and evolution, beginning with the fossil record of larval amphibians and progressing through a discussion of complex life histories in amphibians, heterochrony, development and morphological diversification, and the loss of larvae in many lineages of amphibians. Hanken's approach is strongly phylogenetic, with numerous cladograms used to illustrate evolutionary changes in patterns of development and life history. It should be required reading for any graduate students contemplating work on larval development or amphibian life histories.

Christopher Rose provides an excellent review of hormonal control of larval development in amphibians. His treatment goes beyond standard textbook discussions of the subject, often based on voluminous studies of Xenopus, Rana, and Ambystoma, to include discussions of hormonal control in a wide variety of amphibians, including those with direct development. He also briefly discusses hormonal mediation of viviparity. Another standout chapter is one by Laurie Sanderson and Sarah Kupferberg, which discusses the development, functional morphology, and ecology of larval feeding in both amphibians and fishes. Much of this material has been reviewed in other publications, but this is the best synthesis I have seen and the only one that integrates discussions of filter feeding and suction feeding in both amphibians and fishes. It also is the most ecological of the chapters and clearly illustrates how underlying patterns of development and morphological variation are tied to differences in feeding ecology. This would be an excellent introduction for graduate students interested in larval feeding ecology who know little or nothing about the functional biology of larvae.

A couple of other chapters touch on topics of interest to herpetologists. Eric Greene's chapter on phenotypic variation has a brief discussion of trophic polymorphism and cannibalistic morphs in amphibian larvae, a topic also briefly discussed by Sanderson and Kupferberg. A very short chapter by Michael Hart and Gregory Wray on heterochrony touches briefly on amphibians but is devoted mostly to tunicates. Hanken's chapter has more to offer vertebrate biologists on this topic. The biology of fish larvae is not covered extensively in this book, despite the great interest among ichthyologists in the early life histories of fishes. Nevertheless, the single chapter devoted entirely to larval fishes, by Jacqueline Webb, is an excellent one and is particularly useful for someone who knows next to nothing about the subject. She reviews general patterns of larval fish development, the problems posed by a planktonic lifestyle, and morphological specializations. Her discussion of the morphology and development of the sensory systems is especially detailed. I found this chapter to be a very useful source of information for a vertebrate biology course, because the textbook for that course (Pough et al., 1999) has little to say about larval fishes. I was especially intrigued by her illustrations of the bizarre forms of many larval fishes.

Overall, this book will be a useful reference on the shelves of herpetologists, ichthyologists, and integrative vertebrate biologists. It also will be most useful to researchers in the currently hot field of evolution and development whose interests cut across taxonomic lines between vertebrates and invertebrates.