Integrative species delimitation and conservation of tarantulas (Araneae, Mygalomorphae, Theraphosidae) from a North American biodiversity hotspot BRENT E. HENDRIXSON, 1 ALEXIS V. GUICE 1 and JASON E. BOND 2 1 Department of Biology, Millsaps College, Jackson, MS, USA and 2 Department of Biological Sciences and The Auburn University Museum of Natural History, Auburn University, Auburn, AL, USA Abstract. 1. The Madrean Sky Islands of northern Mexico and the south-wes- tern United States are located in the Madrean pine–oak woodlands ‘biodiversity hotspot’. This area is renowned for its exceptional flora and fauna, but compar- atively little is known about arthropod diversity in this region. We obtained specimens of the tarantula genus Aphonopelma from five different mountain ranges (Huachucas, Pajaritos, Peloncillos, Santa Catalinas, and Santa Ritas) to assess patterns of diversity within the group. 2. Species delimitation in tarantulas is difficult because they possess few informative morphological features. We implemented a rigorous methodological framework for delimiting species that incorporated multiple lines of evidence (molecules, distributional information, morphology, and breeding period) in an explicitly hypothesis-driven manner. 3. Our integrative taxonomic approach delimited three species (all unde- scribed): one endemic to the Peloncillos, one endemic to the Santa Catalinas, and one that is more widely distributed in the Huachucas, Santa Ritas, and Pa- jaritos. These patterns of diversity and endemicity are comparable to other arachnids in the region and suggest that species-level diversity of stenotypic/dis- persal-limited arthropods throughout the Madrean Sky Island Region may be underestimated. 4. Ecological data are not widely available for Madrean Sky Island tarantulas and it is difficult to evaluate their conservation status. Several intrinsic (patterns of endemicity, limited vagility, and life history) and extrinsic (habitat degrada- tion, commercial exploitation, and climate change) factors, however, suggest that these spiders may be of conservation concern. The approach taken in this study highlights the importance of considering multiple lines of evidence when species delimitation has direct implications on conservation. Key words. Aphonopelma, climate change, integrative taxonomy, Madrean pine–oak woodlands, sky islands, spider conservation. Introduction ‘Biodiversity hotspots’ are regions targeted for conserva- tion due to their ‘exceptional concentrations of endemic species’ and ‘loss of habitat’ (Myers et al., 2000). Among these threatened areas are the Madrean pine–oak woodlands of Mexico and the south-western United States Correspondence: Brent E. Hendrixson, Department of Biology, Millsaps College, Jackson, MS 39210, USA. E-mail: brent.hendrixson@millsaps.edu 120 Ó 2014 The Royal Entomological Society Insect Conservation and Diversity (2015) 8, 120–131 doi: 10.1111/icad.12089