Mayorella bigemma (Schaeffer, 1918)

Diagnosis: Locomotive form fairly broad and triangular, sometimes with parallel dorsal folds; subpseudopodia usually present; nucleus spherical with a central nucleolus; cytoplasmic crystals attached to spherical bodies or occurring in pairs; floating form with long, radiating pseudopodia.

Dimensions: Page: 100–300 µm; nucleus 12 µm.
My measurements: 85–190 µm; nucleus 14.4–17.5 µm.

Ecology: Freshwater, typically in Sphagnum bogs.

Remarks: The name bigemma refers to the typical paired crystals attached to spherical bodies. These crystals, however, are not diagnostic for this species.

References: Schaeffer, A. A. (1918). The taxonomy of the amoebas.
Papers of the Department of Marine Biology, Carnegie Institution of Washington, 12: 1–90.