Stercomata

Stercomata (or stercomes) are extracellular pellets of waste material produced by some groups of

The term “sterkome” was first used Schaudinn in 1899 to describe the balls of undigested food remains produced by the testate amoeba Trichosphaerium sieboldi, the foraminiferan Saccammina sphaerica, and the gromiid Gromia dujardinii.[3] Schaudinn conducted feeding experiments on live individuals of Trichosphaerium sieboldi kept in culture dishes to confirm that stercomata were accumulations of waste material produced as a byproduct of feeding.

Taxonomic distribution

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]

Saccamminid foraminiferans

Komokiaceans

Xenophyophores

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

Multichambered, organic-walled foraminiferans

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