Spider diversity and biogeography in deep evolutionary time

IVAN L. F. MAGALHAES

Congreso; 2021 Virtual Meeting of the American Arachnological Society; 2021

American Arachnological Society

Abstract: Spiders are one of the most diverse groups of animals, and thus understanding their evolutionary and biogeographic history is paramount to reveal general patterns in biodiversity. I will start this talk by briefly outlining the current and past diversity of the group to demonstrate that there have been significant changes in spider diversity through time. In particular, I will show that those ancient spider lineages with simple genitalia (?haplogyne? spiders) were the dominant group during the Mesozoic. Because the evolutionary history of haplogyne spiders extends well into ancient times, I will argue that they are particularly suitable to test biogeographic hypotheses on a global scale. To demonstrate this, I will discuss the phylogeny and biogeographic history of sand spiders (Sicarius) and crevice weavers (Filistatidae). These two spider groups occupy habitats with similar climates, and yet they present some contrasting biogeographic patterns. I will discuss possible explanations for this observation, and suggest that we need more basic information on spider natural history and dispersal to further refine biogeographic studies.