Books : reviews

Jennifer A. Clack.
Gaining Ground: the origin and evolution of tetrapods: 2nd edn.
Indiana University Press. 2012

Around 370 million years ago, a distant relative of a modern lungfish began a most extraordinary adventure – emerging from the water and laying claim to the land. Over the next 70 million years, this tentative beachhead had developed into a worldwide colonization by ever-increasing varieties of four-limbed creatures known as tetrapods, the ancestors of all vertebrate life on land.

This new edition of Jennifer A. Clack’s groundbreakmg book tells the complex story of their emergence and evolution. Beginning with their closest relatives, the lobe-fin fishes such as lungfishes and coelocanths, Clack defines what tetrapods are, describes their anatomy, and explains how they are related to other vertebrates. She looks at the Devonian environment in which they evolved, describes the known and newly discovered species, and explores the order and timing of anatomical changes that occurred during the fish-to-tetrapod transition.

Clack explains how older ideas about the transition are being overturned by recent discoveries and new ideas about evolutionary change. Moving from the Devonian to the Carboniferous, she follows the radiation of terrestrial tetrapods, including some of the most recent discoveries, and includes an in-depth look at a spectacular locality for Early Carboniferous tetrapods. She discusses the relationships among Paleozoic tetrapod groups, and between them and modern amphibians, and provides a coherent picture,of early tetrapod evolution and their adaptations to life on land.