<i>Vampyrella crystallifera</i> 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 <i>Vampyrella</i> 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 <i>Vampyrella</i> species and vampyrellid amoebae in general. Here, we report on a new species from a German spring fen, <i>Vampyrella crystallifera</i> sp. nov., which specifically preys on a unicellular zygnematophyte green alga (<i>Nucleotaenium</i> sp.) isolated from the same microhabitat. In contrast to its closest relatives (<i>V. lateritia</i> and <i>V. pendula</i>), <i>V. crystallifera</i> 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 <i>V. crystallifera</i> again showcases the exceptional diversity of predator-prey interactions found in the Vampyrellida and adds to our knowledge of protist diversity in temperate moorlands.