The seasonal, cross-hemisphere migration of the Atlantic Intertropical Convergence Zone (ITCZ) and its transition into distinct tropical monsoon systems, the South American and the African monsoons, delivers substantial precipitation into the South American and African continents. These atmospheric circulations drive continental hydroclimate and consequently regulate the expansion and contraction of the regional tropical rainforest systems. The ITCZ and monsoons are strongly influenced by the position of the surrounding landmasses (Gill, 1980; Privé & Plumb, 2007b), which differed substantially in the past (Pletsch et al., 2001; Seton et al., 2012). For example, based on paleoclimate simulations of the late Paleozoic and early Mesozoic (∼250 Ma), when the South American and African continents was the West Gondwana mega-continent, a single "mega-monsoon" system