Foraminifera

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]

Gromiida

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]

Testate Amoebae