Two New Cryptic Endemic Toads of Bufo Discovered in Central Nevada, Western United States (Amphibia: Bufonidae: Bufo [Anaxyrus])

Abstract

We describe two new cryptic species of Bufo within the subgenus Anaxyrus discovered in Central Nevada of the western United States. Our analyses revealed that these two localized endemic toads are genetically divergent and morphologically distinct, yet were concealed under the range of the broadly distributed western toad (Bufo boreas), which occurs throughout Nevada. The newly discovered species are close in geographic proximity to each other (albeit, in different hydrological basins) but have evolved unique morphological characters that are distinct from each other and distinctive from all allied taxa within the B. boreas species complex. The delimiting of these two rare toads emphasizes the link between taxonomic crypsis and inadequate conservation as these newly described species are vulnerable to extinction due to severely restricted geographic ranges, unknown population sizes, and dependency on rare, fragile wetland habitat, which is a limited resource within Nevada, the primary state that makes up the arid Great Basin. These two endemics join the Great Basin B. boreas species complex as imperiled new members, and our study demonstrates that our knowledge of anuran diversity is incomplete and that new discoveries can still be made, even in unlikely settings.