The Allogromiida are a group of monothalamous (single-chambered), mostly organic-walled foraminifera

Foraminifera

The Foraminifera , or forams for short, are a large group of amoeboid protists which are among the commonest plankton species. They have reticulating pseudopods, fine strands of cytoplasm that branch and merge to form a dynamic net...

ns, including some that produce agglutinated tests (Lagynacea). Genetic studies have shown that some foraminiferans with agglutinated tests, previously included in the Textulariida

Textulariida

The Textulariida is a group of common foraminiferans that produce agglutinated shells, composed of foreign particles held in an organic or calcareous cement. Commonly the order is taken to include all such species, but genetic studies indicate that they are not all closely related, and several...

 or as their own order Astrorhizida, also belong here. Allogromiids produce relatively simple tests, usually with a single chamber, similar to those of other protists such as Gromia

Gromia

Gromia is a widespread genus of marine and freshwater amoeboids, closely resembling some foraminiferans. It produces an organic test, which is ovoid or lobed and may exceed one millimetre in size; this resembles a small grape, in that its centre is fluid-filled but lacks organic matter, which is...

. They are found in both marine and freshwater forms, and are the oldest forams known from the fossil record.