Fig. 1: Simplified evolutionary history of foraminifera.

The scheme depicts the diversification of foraminifera from their emergence in the Precambrian until the end of the Mesozoic with a simplified stratigraphy. The polytomies reflect uncertainties in the evolutionary relationships between the depicted lineages. The Globothalamea and Tubothalamea have a class rank and the status of the Monothalamea is uncertain. The relationship of Lagenida to other foraminifera lineages is unclear but it is a distinct lineage from the three other main clades. The open circles approximately indicate when completely biomineralized shells appeared in each lineage. The figure is based on refs. 9, 11, 57, 58.