Sarcodina

The Sarcodina include Protista that form pseudopods, temporary cytoplasmic projections that are involved in locomotion and ingesting food. The different amoeboid body forms have evolved a number of times, and come in four main groups: those with lobose, filose, and reticulose pseudopods, which are unsupported, and those with axopods, which are rigid projections around microtubules.

The main groups of protists with axopods are:

:Actinophryida

:Centrohelida

:Desmothoracida

:Gymnosphaerida

:Acantharea

:Polycystinea

:Phaeodarea

The last three of these are collectively referred to as the Radiolaria, and are typically marine forms with intricate mineral skeletons. The others, collectively referred to as the Heliozoa, are typically freshwater forms, usually sphere-shaped and covered in ray-like axopods that gather food (hence the name, sun animal).

Reticulose pseudopods are cytoplosmic strands that branch and anastomose to form a net. They are found among the Granuloreticulosa, which includes primarily the Foraminifera - marine amoeboids with multichambered tests.

Lobose pseudopods are blunt and filose pseudopods are tapering, occasionally branching, but both arise from the same sort of underlying pressure system. These are the kinds of pseudopods familiar to us from Amoeba and its kin. The main groups of such protists are:

:Ramicristates - most lobose and filose forms, including most slime mold groups

:Pelobionta - giant amoebae & kin

:Entamoebae - mostly parasitic forms

:Heterolobosea - amoeboflagellates, including acrasid slime molds

There is also a strange group of giant marine protists, the Xenophyophorea, that are clearly amoeboid but do not fit nicely into any of these categories.