The nearshore cradle of early vertebrate diversification

Abstract

Shallow-water diversification Most of what we know about the relationship between diversification and environment in ancient marine environments has come from invertebrates. The influence of habitat on vertebrate diversification thus remains a persistent question. Sallan et al. studied fossil vertebrates spanning the mid-Paleozoic, including both jawed and jawless fish (see the Perspective by Pimiento). They found that diversification occurred primarily in nearshore environments, with diversified forms later colonizing deeper marine or freshwater habitats. Furthermore, more robust forms remained in the nearshore, whereas more gracile forms moved to deeper waters. This split is similar to current relationships between form and environment in aquatic habitats. Science , this issue p. 460 ; see also p. 402