Introduction

While there are several excellent field guides that cover identification of reptiles and amphibians in the United States, the striking geographic variation, occasional sexual dimorphism, and developmental changes of species over this large geographic range can confuse identification. The highly developed and urbanized area of coastal Southern California is host to one of the richest herpetofaunas in the United States and includes several species with State and Federal protected status. Over the past few years, we have been conducting an intensive study of the autecology of herptile communities in the region and saw the pressing need for a well-illustrated field guide to help train students, researchers, reserve managers, regulators, and others to identify the local herpetofauna, with emphasis on sensitive species. We recognized this need in the wake of a proliferation of environmental documents (gray literature) and reviews dealing with many species that are either poorly known or commonly misidentified. Our goal is that this guide, by aiding in the correct identification of species, will increase the understanding of this group and the utility of biology work currently underway in southern California. As this project progressed it became clear that by covering all the species, including very localized ones, we would appeal to a larger audience and hopefully spawn interest in this very diverse, threatened fauna. This fauna is especially rich due to the co-occurrence of mountain, desert, scrub, and Baja elements in the heterogeneous habitat available on the coastal slope. This book includes all the species that are native in the geographic focal area (see map). Subspecies are included as well, when they may be distinguished by characters in the field (e.g. the California mountain kingsnake and red racer). We do not attempt to distinguish the subspecies of the western skink or the ring-necked snake. This choice is not meant to imply any taxonomic reanalysis (although this may be called for in the future). Introduced species are included if they are relatively widespread and seem to have self-sustaining natural populations. For example, we have excluded Anolis and desert tortoises. The former is distributed in the immediate vicinity of the San Diego Zoo and the latter shows up as occasional escaped pets. Marine and island species were not included in this guide.