Drawing

Description:

Calliacantha frigida Thomsen, Garrison and Kosman, 1997. Choanoflagellates cells which occur as individuals. The cell body is about 4 x 8 microns long, with a pointed posterior end. The single flagellum (about 30 microns) is surrounded by a ring of tentacles that form the collar. The conical lorica chamber (10 - 14 microns long) consists of 2 transverse costae and 6 (7) longitudinal costae. The transverse costae (diameter about 5 and 4 microns respectively) are closely spaced (1 - 2 microns) at the anterior chamber end. Six rather short costal strips (about 4 microns) form part of the anterior transverse costa, whereas the posterior transverse costa appears to consist of fewer costal strips. Anterior transverse and longitudinal costal strips form E-joins. Each longitudinal costa is composed of two costal strips, each 6 - 8.5 microns long. The costae continue above the anterior transverse costa forming projections that become narrower and are about one costal strip in length (about 9.5 - 12.5 microns). The projections in the living cell lie almost perpendicular to the longitudinal axis of the lorica. The number of longitudinal costae is less towards the hind end of the lorica chamber due to the amalgamation in pairs and threes of costal strips. The lorica is terminated by an aggregated pedicel formed of 3-5 bundled costal strips are each 7 - 9.5 microns long. They have swollen and clawed posterior tips and they often diverge to form a larger holdfast area. A protoplast suspensory membrane extends from the base of the lorica chamber to the level of the posteriormost transverse costa. Replication tectiform.