Taxonomic revision of freshwater foraminifera with the description of two new agglutinated species and genera.

Most foraminifera inhabit marine habitats, but some species of monothalamids have been described from freshwater environments, mainly from Swiss water bodies over 100 years ago. Recent environmental DNA surveys revealed the presence of four major phylogenetic clades of freshwater foraminifera. However, until now only one of them (clade 2) has been associated to a morphologically described taxon-the family Reticulomyxidae. Here, we present morphological and molecular data for the genera representing the three remaining clades. We describe two new agglutinated freshwater genera from China and the Netherlands, Lacogromia and Limnogromia, which represent clades 3 and 4, respectively. We also report the first ribosomal DNA sequences of the genus Lieberkuehnia, which place this genus within clade 1. Our study provides the first morphotaxonomic documentation of molecular clades of freshwater foraminifera, showing that the environmental DNA sequences correspond to the agglutinated monothalamous species, morphologically similar to those described 100 years ago.