Global diversification of Anelosimus spiders driven by long distance overwater dispersal and Neogene climate oscillations

Vicariance and dispersal events, combined with intricate global climatic history, have left an imprint on the spatiotemporal distribution and diversity of many organisms. Anelosimus cobweb spiders (Theridiidae), are solitary-social organisms with a cosmopolitan distribution in temperate- to-tropical areas. Their evolutionary history and the discontinuous distribution of species richness suggest that 1) long distance overwater dispersal, and 2) climate change during the Neogene (23–2.6 Ma), may be major factors in explaining their distribution and diversification. Here we test these hypotheses, and explicitly test if global Miocene/Pliocene climatic cooling in the last 8 Ma affected Anelosimus radiation in parallel in South America and Madagascar. To do so, we investigate the phylogeny and spatiotemporal biogeography of Anelosimus through a culmination of a 20-year comprehensive global sampling at the species level (69 species, including 84% of the known 75 species worldwide, represented...