Pyxidicula sp. 

Diagnosis: Shell membranous, rounded, helmet-shaped in lateral view, reminiscent of WWI helmets. Composed of small building units. The domed portion of the shell exhibits very faint hemispherical depressions. Shell translucent and yellowish. Aperture large, circular, with a distinct rim.

Dimensions: Diameter 141-158 µm, height about 66 µm, rim about 12 µm (n=4).

Ecology: Mosses, Equador.

Remarks: I found four empty shells in a moss sample from Ecuador. They resemble P. ornata. One shell had a flat top (see image above). It is not clear whether this was normal or caused by pressure.