Description of Mastigella commutans
provided by BioPedia
Cells are rounded, cylindrical or pear-shaped when motile and are 12-30 microns long. A single flagellum up to 60 microns long is present in about half the cells. Cells are amoeboid while stationary, and the flagellum can arise from any part of the cell surface. Cells become elongated when gliding and have the flagellum directed anteriorly. The flagellum has a languid spiral or undulating base-to-tip beating pattern. The single observed nucleus is not closely associated with the base of the flagellum. The anterior quarter to half of moving cells is usually hyaline. Food vacuoles and endosymbiotic bacteria may be visible posteriorly. Pseudopodia may be lobose or filose, with the filose pseudopodia most commonly observed during swimming. In the region of the flagellar insertion, pseudopodia may form suddenly (i.e. are eruptive). A contractile vacuole is located posteriorly, and fills by fusion of smaller vesicles. No large multinucleate forms or cysts have been observed.
