Fig. 2: Models used in FSC2 to understand the demographic processes leading to the two-population pattern of diversification in the corkscrew anemone Bartholomea annulata across the Tropical Western Atlantic.

Each model is a two-population isolation-migration (IM) model that varies in the degree and directionality of gene flow and effective population size. Models are as follows: a isolation only, b isolation with population size changes following divergence, c IM model with symmetric migration, d IM model with symmetric migration and population size changes, e IM model with migration from the Western to Eastern population, f IM model with migration from the Eastern to Western population, g IM model with symmetric migration between populations immediately following divergence followed by more contemporary isolation, h IM model with isolation immediately following divergence, followed by secondary contact and symmetric migration, i IM model with migration from the Western to Eastern population immediately following divergence, followed by more contemporary isolation, j IM model with isolation immediately following divergence followed by secondary contact and migration from the Western to Eastern population, k IM model with migration from the Eastern to Western population immediately following divergence, followed by more contemporary isolation, and l IM model with isolation immediately following divergence followed by secondary contact and migration from the Eastern to Western population. Model 6 was selected by Akaike Information Criterion as the best fit demographic model for both holobiont and aposymbiotic datasets.