Description of Acanthocorbis nana:
Cells solitary, attached to the substratum by means of single costal strips projecting from the posterior lorica end. Lorica funnel shaped, about 10 x 5 microns, and with anterior long spines (10-14) that continue downwards as longitudinal costae. Numerous, obliquely oriented transverse costal strips (>20) encircle the lorica at the level of or just below the joins between the anterior most longitudinal costal strips. The posterior part of the lorica encompasses numerous transverse costal strips that do not form distinct costae. Costal strips are rod-shaped, and 3-4 microns long. The cell body, about 4.5x3.5 microns, is posteriorly located within the lorica. The single flagellum is about 5 microns long, surrounded by a ring of tentacles (each about 2microns long), and with a conspicuous hairpoint. Division tectiform.