Figure 5. Phenotypes of T. adhaerens change at various feeding conditions.

T. adhaerens acquires various body shapes in individual cultures dependent on food availability and composition. At conditions maintained in stable and biologically equilibrated stock aquariums, T. adhaerens is usually small and pale with diameter varying from 50 µm to 400 µm while cultures with added algae contain large flat animals with diameter reaching up to 1 mm (A and B). In some cultures, animals grow as long stretching structures, reaching a length exceeding one or even several centimeters (C). The algal food makes the animals greenish, reddish, rusty or brown with variable proportion of prominent dark cells. Animal shapes also vary from flat and round with smooth circumference, to curved or ruffled circumference or animals with long projections. Bars represent 1 mm in (A, B, I), 1 cm in C, 250 µm in (D), 500 µm in (E and H), 200 µm in (F) , and 100 µm in (G).