Stercomata

Stercomata are produced by members of several different subclades of Foraminifera that possess organic-walled or agglutinated tests, including: single-chambered taxa with spherical organic-walled tests (e.g., Bathyallogromia and other undescribed species),[4] single-chambered taxa with sac-like agglutinated tests (e.g., Saccammina and Leptammina),[5] single-chambered taxa with tubular agglutinated tests (e.g., Bathysiphon),[6] multi-chambered taxa with organic-walled tests (e.g., Nodellum and Resigella),[7] taxa with complex agglutinated tests composed of delicate branching tubes (Komokioidea),[8] and deep-sea taxa with large, complex tests agglutinated tests (Xenophyophorea).[1]

In xenophyophores, the stercomata are contained within an organic tubes called stercomare.

Gromiida is a subclade of Endomyxa, a clade that branches within the more inclusive group Rhizaria, a clade that encompasses a diverse array free-living and parasitic single-celled eukaryotes that possess branching or anastomosing pseudopodia and complex life cycles.[9] [10]

In Gromia, the only described genus of Gromiida, stercomata are spherical to ovoid in shape and range in color from brown to gray to orange.[11] [12] [13] Individual stercomes range in size from <5 µm (G. psammophila) to 15-30 µm (G. saoirsei).[13] Stercomata consist of the undigested remains of ingested food and may include mineral grains, sponge spicules and diatoms, which are held together by glycosaminoglycans.[12] [14] Unlike the stercomata in foraminiferans, the stercomata in gromiids are retained in the cytoplasm and not stored outside of the cell body; however, after the release of flagellated gametes during sexual reproduction, the stercomata remain in the interior of the test.[14]