Acanthocystis cornuta  Dürrschmidt, 1987

Diagnosis: Periplast 15-20 µm in diameter. Protoplast unknown. Spine-scales 3.2-4.4 µm long. Shaft 0.1 μm thick, cylindrical, hollow. Apex bifurcated, each tip, approx. 1 µm long, on the inside with 2-4 sharp teeth, smooth outside. Central round basal disc, 0.5 µm on average. Tangential plate-scales 2.3-3 x 1.5-1.9 µm, elliptical with narrow peripheral bar, with axial thickening and weakly developed radial gaps. This species resembles A. pectinata, A. bicornis, and A. radiosa Roskin 1929 by light microscopy.

Geographical distribution: Swamp forest. Chile, New Zealand, Canada.