Amoeboid

The amoeboids comprise those Protista that form pseudopods, temporary cytoplasmic projections that are involved in locomotion and ingesting food. Originally they were grouped together as the Sarcodina, but the different sorts of amoeboid forms have each evolved a number of times. These 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 cytoplasmic strands that branch and anastomose to form a net. They are found among the Granuloreticulosa?, which includes primarily the Foraminifera? - marine amoeboids with multichambered shells.

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. Amoeboid cells also occur in a few multicellular organisms, e.g. white blood cells have a lobose amoeboid form.