Deep genetic divergence in the Deep South: An integrative approach to species delimitation reveals the paraphyletic nature of speciation in the trapdoor spider genus Cyclocosmia.

Abstract

Mygalomorph spiders house an incredible amount of cryptic genetic information, making them an excellent model for species delimitation. An integrative approach to species delimitation uses multiple lines of evidence to increase objectivity and greater accuracy. We apply an integrative approach to the trapdoor spider genus Cyclocosmia. Both discovery (concatenation) and validation (Bayes factor delimitation) were used. These methods found strong structuring across the landscape and paraphyletic speciation. The results of these methods contrasted starkly with the morphology, which was supported as two species using a morphometric analysis. Gene flow is an important aspect of speciation and was investigated using the program PHRAPL, which found overall relatively low levels of migration. Niche differences and the projected distributions of these species were calculated using niche based distribution modeling. Based on these integrated methods, the refined hypothesis for this group is three species.