Order THAUMATOMONADIDA Shirkina, 1987
Genus Thaumatomastix Lauterborn, 1899; emend. Howe et al., 2011
Diagnosis: Freshwater non-plasmodial thaumatomonads with prominent nucleus, spine scales, and triangular 1 µm thick plate scales visible in light microscope as a peripheral double layer with ‘boxed’ substructure. Plate scales two-tiered with upper and lower tier of the same size. Spine scales like somewhat smaller plate scales with long eccentrically placed spine,without basal flange, stemming at a slant from beside central hole in two-tiered base. Plate scales and spine-scale triangular bases with gently rounded vertices. Posterior cilium longer than cell; non-scaly anterior cilium half to 2/3 cell length.Ventral pseudopodia.
Type species: Thaumatomastix setifera Lauterborn, 1899.
Other species: Tx triangulata (Balonov1980), nigeriensis (Wujek et al. 2008).