The Rhizaria are a species-rich supergroup of unicellulareukaryotes. They vary considerably in form, but for the most part they're amoeboids with filose, reticulose, or microtubule-supported pseudopods. Many produce shells or skeletons, which may be quite complex in structure, and these make up the vast majority of protozoan fossils. Nearly all have mitochondria with tubular cristae. Groups There're three main groups of Rhizaria: Cercozoa - Various amoebae and flagellates, usually with filose… (More on Rhizaria)