Systematics and biogeography of the widespread Neotropical gekkonid genusThecadactylus(Squamata), with the description of a new cryptic species

The systematics of the widespread neotropical gekkonid genus Thecadactylus is investigated using a combination of morphological, morphometric and mtDNA (cytochrome b ) sequence data, forming a total evidence dataset.The analysis tackles the common yet complex problem of a widespread taxon consisting of one or more cryptic species that are difficult to diagnose using morphology alone.The data are analysed using both maximum parsimony and Bayesian inference.Virtually all analyses resolve a well-supported south-western Amazonian clade distinct from the remainder of the recognized T. rapicauda .The south-western Amazonian clade is not only robustly supported, but also exclusive, geographically coherent and sufficiently distinct to warrant specific recognition.The new species is diagnosable on the basis of molecular sequences that are 23.0-26.9%divergent from those of T. rapicauda , and morphological evidence.Bayesian inference analysis robustly resolves meaningful and repeatable patterns of relationship.The biogeography of Thecadactylus is interpreted in the context of its two constituent species, and difficulties of resolving systematic and biogeographical patterns in widespread, cosmopolitan taxa are discussed.