“…Exploring the extent of population structure and its causes can be used to test between the ubiquity and moderate endemicity models, as the former predicts a lack of divergence in allopatry or isolation by distance, and little evidence for recent speciation events, in contrast to what is observed in many plants and animals. Evidence for genetically structured populations has recently been reported across a variety of taxa and habitats, including examples from ciliates (Zufall, Dimond, & Doerder, 2013), amoebae (Douglas, Kronforst, Queller, & Strassmann, 2011;Heger, Mitchell, & Leander, 2013), diatoms (Casteleyn et al, 2010;Sjöqvist, Godhe, Jonsson, Sundqvist, & Kremp, 2015;Vanormelingen et al, 2015;Whittaker & Rynearson, 2017), dinoflagellates (Lowe, Martin, Montagnes, & Watts, 2012;Rengefors, Logares, & Laybourn-Parry, 2012), raphidophytes (Lebret, Tesson, Kritzberg, Tomas, & Rengefors, 2015) and fungi (Carriconde et al, 2008;Ellison et al, 2011). While many of these studies showed clear evidence for geographic structure (supporting the moderate endemicity model), the majority were limited in resolution due to the small number of marker loci used.…”