Drawing

Description:

Monotrichomonas carabina Bernard et al., 1999. Cells 5 to 11 microns long, often with a fine posterior spike which may be as long as the body. Cells are bi-flagellated and normally rounded. The anterior flagellum inserts slightly subapically and is two to three times the length of the body. The posterior flagellum inserts slightly more posteriorly in a latero-posterior plane and is one to two times the length of the body. The proximal portion of the posterior flagellum attaches to the cell body as an undulating membrane, ranging from less than 2 pm long to almost the whole length of the cell. There is a small apical crest. The nucleus is located anteriorly and is surrounded by small, closely packed granules. In some cells a delicate cone of cytoskeletal material was observed running from the nuclear region to merge with the posterior spike. Food vacuoles contain bacteria. Cells swim with a jerky spiralling progression, with the anterior flagellum beating with a clawing motion and the posterior flagellum beating with wide amplitude waves. Compressed or detritus-bound cells may be very plastic, may occasionally produce fine cytoplasmic threads and may glide. During gliding, the distal portion of the flagellum forms a three-quarter loop which travels down the flagellum during cell movement, but is held stationary relative to the substrate. When the loop reaches the proximal end of the flagellum, the movement stops and the flagellum unloops. Further gliding may occur with the flagellum extending anteriorly and forming a new distal loop.