Morphological and molecular systematics and biogeography of Mygalomorph spiders of Atlantic Forest

Abstract

The infraorder Mygalomorphae (Araneae) are currently divided into 16 families, 11 of those occur in Brazil: Actinopodidae, Barychelidae, Ctenizidae, Cyrtaucheniidae, Dipluridae, Idiopidae, Mecicobothriidae, Microstigmatidae, Nemesiidae, Paratropididae e Theraphosidae. These spiders show high morphological uniformity, making it difficult the proposition of phenotypic homologies. Furthermore, the traditional method of delimiting species based on morphology, in many cases, involves few characters, being restricted to minor details, which are hard to quantify. Mygalomorphs show limited dispersal skills and are sedentary spiders with high fidelity to their retreat. In this scenario, delimiting species and investigating phylogenetic relationships becomes a though task, requiring distinct sources of evidence. Moreover, low dispersal skills make these spiders susceptible to population divergence, which may lead to speciation processes (vicariance and/or parapatric divergence), representing objects to be explored in biogeographic approaches. Recent studies with opilionids and anurans showed the south and southeastern portions of Brazilian Atlantic Forest as a complex mosaic of areas of endemism. We aim to understand the significance of morphological and molecular characters in systematic studies for Mygalomorphae spiders, more specifically concerning the limits among species and how these distinct types of evidence interact. A total of eight sympatric mygalomorph genera were select for the present proposal: Vitalius Lucas, Silva e Bertani, Grammostola Simon, Rachias Simon, Homoeomma Ausserer, Prorachias Mello-Leitão e Pycnothele Chamberlin. Each of these genera will be studied under morphological, molecular and biogeographic approaches. The research group assembled for this proposal includes undergrad, postgrad and researchers working on distinct taxa and approaches, establishing the Spider Systematics Lab in UNESP Rio Claro. We expect to generate data for publication regarding the systematics of all genera included here, as well as promoting information for more detailed biogeographic studies and future molecular works (tissue collection). (AU)