(phylum Protozoa, subphylum Sarcomastigophora)
A superclass of protozoa which form pseudopodia for feeding and locomotion. There are three classes, and many orders. The majority of species live in marine aquatic environments but some occur in fresh water (and are important members of the soil fauna) and some are parasitic in the intestinal tracts of vertebrates and invertebrates. The superclass includes the Radiolaria, known from the Cambrian, and the Heliozoa, which are exclusively freshwater and have a fossil record that extends back only to the Pleistocene.
Subjects: Zoology and Animal Sciences.