Actinophrys (Protozoan) Movies

Actinophrys Video No. 1 - An actinophrys explores its world with gently waving axopodia; under phase contrast illumination at a magnification of 200x with a playing time of 26.2 seconds. Choose a playback format that matches your connection speed: 28.8k (modem), 56.6k (modem), or T1/Cable/DSL, or download this video clip in MPEG format (10.9 MB).

Actinophrys Video No. 2 - An actinophrys engulfs a morsel of food; under phase contrast illumination at a magnification of 200x with a playing time of 16.8 seconds. Choose a playback format that matches your connection speed: 28.8k (modem), 56.6k (modem), or T1/Cable/DSL, or download this video clip in MPEG format (7.02 MB).

Originally named "Sun Animalcules," these predatory organisms belong to the protozoan class Heliozoa (superclass Actinopoda). They are found most often in freshwater, floating in the open water amongst reeds and filamentous algae. Actinophrys is notable for having more than one nucleus. In general, heliozoans are spherical and are frequently enveloped by a shell, or test, made of silica or organic material. Organisms secrete the shell in the form of scales or pieces in a gelatinous covering. The shells exhibit a wide variety of shapes, which can be used in species identification. Heliozoans reproduce asexually by binary fission or by budding, but several genera have flagellated forms that may possibly be sex gametes.