Calliacantha ankyra Thomsen, Garrison and Kosman, 1997. Cells are solitary. Protoplast (5-7x3-5 microns), pointed at the posterior end and with a single anterior flagellum (about 20 microns) surrounded by a collar of tentacles. Lorica chamber formed by 6 posteriorly converging longitudinal costal strips (8-11 microns) and anteriorly delimited by two closely spaced transverse costae (diameter 4-5 microns). Anterior joins between transverse and longitudinal costal strips are modified E-joins. The longitudinal costae continue above the anterior transverse costa as diverging projections, which are equal to one costal strip in length (9-12 microns). The aggregated pedicel is formed by two sets of bundled longitudinal costal strips. Two costal strips (8-12 microns long) typically form the uppermost set. The posterior most longitudinal costal strips (about 5, 8.5-11.5 microns long) diverge to form a better holdfast. Each strip is characterized by a swollen and clawed posterior tip. A protoplast suspensory membrane lines the lorica chamber. Division tectiform.
