Cryptodifflugia leachi is an aquatic species of testate amoebae discovered in 2006 in Canada, living in bottom sediment from wetlands at the base of the Niagara Escarpment.

[2] Cryptodifflugia leachi is characterized by an oval, elliptical shell with a circular transverse section and a smooth surface.

The shell ranks as one of the smallest out of the testate amoebae, with a length of 10-16 μm, a width of 8-12 μm and a very small pseudostomal aperture of 1.5-2.5 μm in diameter.

[2][1] Its pseudopodia are narrow and cylindrical, often reaching lengths up to 3 times that of the shell.

Inside its cytoplasm there are often one or two large crystal-like refractive bodies in the anterior (closer to the aperture) region.