Aphagea is a group of obligate osmotrophic protists. They are euglenids, flagellates with two flagella and a relatively flexible cell shape underlined with protein strips. Unlike other euglenids, they feed only by osmotrophy, and lack any specialized structure for ingestion. Their closest living relative is Neometanema, a genus of phagotrophic (ingestion-feeding) euglenids, together forming the taxon Natomonadida.