Sarcodina

Sarcodina is a former taxonomic group within the Protista kingdom, now largely considered a polyphyletic assemblage rather than a true taxon. Organisms classified under Sarcodina are characterized by their ability to move and feed using pseudopodia, which are temporary extensions of their cytoplasm. These pseudopodia, meaning "false feet," are crucial for locomotion and engulfing food particles through phagocytosis.

The group historically included amoebas, foraminiferans, and heliozoans. Amoebas are perhaps the most well-known members, typically free-living in aquatic or soil environments, though some are parasitic. Foraminiferans are marine protozoa that often possess a calcareous shell, leaving behind fossil records that are important in paleontology. Heliozoans are mostly freshwater organisms with ray-like pseudopodia.

Modern classification has largely dispersed the organisms once grouped as Sarcodina into different phyla and classes, primarily within the Amoebozoa and Rhizaria supergroups. This reclassification reflects a better understanding of their evolutionary relationships, which were not accurately represented by the morphological similarity of pseudopod formation. Despite its outdated status as a formal taxonomic rank, the term "sarcodine" is still sometimes used informally to refer to protozoa that exhibit this mode of locomotion and feeding.