A clade of eukaryotic protists comprising the testate (shelled) amoebas. Although constructed chiefly on the basis of molecular systematics, the group features threadlike (filose) pseudopodia. Members include radiolarians with their intricately sculpted siliceous skeletons; the foraminiferans, characterized by pore-covered shells made of sand or organic materials; and the cercozoans, such as the euglyphid amoebas. Some authorities now regard the rhizarians as members of the SAR supergroup, along with the alveolates and stramenopiles.