Biogeography of New World Tarantulas

Abstract

Biogeography is a multidisciplinary field that is concerned with delimit- ing and explaining the geographic distributions of organisms in space and time. Due to their distribution patterns and interesting biology (e.g., ancient lineage with a nearly cosmopolitan distribution, sedentary lifestyle with limited dispersal capabili- ties), tarantulas are an appealing taxonomic group for addressing a variety of bio- geographic questions concerning the Earth’s history. In this chapter, we discuss some biogeographic basic concepts, delve into the distribution patterns of New World tarantulas, and explore some of the historical explanations that may have led to these distributions. We mostly review and highlight the results of recent studies but also include personal observations and unpublished data. The distributions of higher-level taxonomic groups (subfamilies and tribes) are described and we detail their latitudinal and elevational limits. We also review the distributions of groups with unique insular habitats such as those found on islands surrounded by seas, forested “islands” surrounded by “seas” of deserts, and caves. Furthermore, we dis- cuss the distribution of some unique morphological characters of taxonomic impor- tance such as urticating setae. Finally, we review a handful of studies that have explicitly investigated the biogeography of New World tarantulas using a variety of different analytical methods.