Genus Netzelia Ogden, 1979

Diagnosis: The shell is ovoid and circular in cross-section. The aperture is lobed and features a thick organic rim or “necklace,” composed of small idiosomes (self-produced siliceous elements). Netzelia differs from Difflugia in its ability to construct its test entirely from idiosomes, though it may occasionally incorporate foreign material (xenosomes), such as mineral grains or diatom frustules.

A key distinguishing feature of Netzelia is the presence of embedded idiosomes, which often exhibit a characteristic “nail” shape. The proportion of these elements in the shell matrix depends partly on the availability of other siliceous materials. However, Netzelia is capable of building a complete shell using only idiosomes. The dimensions of the “nails” may vary, though such variation is typically limited to the length of the shaft, not the diameter of the head (Ogden and Meisterfeld, 1989).