RESUMO
Diversity of the anaerobic Heterolobosea (Excavata: Discoba) is only poorly understood, especially in marine environments. We have isolated and cultured 16 strains of anaerobic heteroloboseid amoebae and flagellates from brackish, marine and saline anoxic habitats worldwide. Phylogenetic analyses of SSU rDNA sequences and light-microscopic observations showed that all the strains belong to the family Psalteriomonadidae, the main anaerobic lineage of Heterolobosea, and that they represent eight species from the genera Monopylocystis, Harpagon and Pseudoharpagon. Seven species are newly isolated and described here as Monopylocystis minor n. sp., Monopylocystis robusta n. sp., Monopylocystis elegans n. sp., Monopylocystis disparata n. sp., Harpagon salinus n. sp., Pseudoharpagon longus n. sp. and Pseudoharpagon tertius n. sp. Amoebae, cysts and the ultrastructure of the genus Pseudoharpagon are presented for the first time.