Sp. Nov., an Amoeba That Dissolves Entire Algal Cells at a Remarkable Speed

The vampyrellid amoebae (Order Vampyrellida, Rhizaria) comprise predatory microeukaryotes that inhabit freshwater, marine, and terrestrial habitats. They are known to consume a wide array of prey, which includes microalgae, fungi, and even microscopic animals such as nematodes. Members of the popular genus phagocytize the cell contents of filamentous green algae after localized perforation of the cell wall. This feeding strategy, named protoplast extraction, is the hallmark of species and vampyrellid amoebae in general. Here, we report on a new species from a German spring fen, sp. nov., which specifically preys on a unicellular zygnematophyte green alga ( sp.) isolated from the same microhabitat. In contrast to its closest relatives ( and ), does not feed by protoplast extraction but engulfs whole algal cells, followed by the dissolution of the entire prey cell wall. Given the recalcitrant, plant-like cell walls of the zygnematophytes, this is a remarkable process that might involve enzymes also used by the closely related protoplast feeders. The discovery of again showcases the exceptional diversity of predator-prey interactions found in the Vampyrellida and adds to our knowledge of protist diversity in temperate moorlands.