General morphology of Lacogromia cassipara. ah - apertural hyaloplasm; p – peduncle; e - entosolenian tube; g – granuloreticulopodia; n – nucleus; m - membrane; x – xenosomes; c - cap of adhering bunch of xenosomes.



Class 'Monothalamea' (Pawlowski et al. 2013)


Diagnosis: Foraminifera with single chamber (monothalamous) test with an organic or agglutinated wall.


Remarks: Monothalamid foraminifera are widely distributed in marine and brackish habitats. Some members of this class occur in fresh water, but are rare. The main reason is probably that light microscopically these tests are hard to discover between debris, despite of their relatively large size (average 250 µm, but up to 1 mm). Usually the amoebae spread out their beautiful pseudopodial network when kept on microscope slides in moist chambers or in culture dishes, up to several mm.

Recent environmental DNA surveys revealed the presence of four major phylogenetic groups or clades of freshwater foraminifera. However, only from one genus in each group its light microscopical morphology could be linked to environmental DNA:

Clade 1: Lieberkuehnia
Clade 2: Reticulomyxa
Clade 3: Lacogromia
Clade 4: Limnogromia


Lacogromia cassipara, morphotype B; a adult specimen; b young specimens, just 24 hours after schizogony - drawing and micrograph Ferry Siemensma (1982)
Lacogromia cassipara, four young specimens, just 24 hours after schizogony (Siemensma, 1982)