Cercozoans

Bodomorpha (bow-dough-more-fa) is a small cercomonad flagellate, virtually indistinguishable from Heteromita, although said to ingest food with pseudopodia formed posteriorly. With two flagella inserting subapically. Mostly from freshwater and soil. Phase contrast micrograph.

Bodomorpha minima Hollande, 1942. Cells are oval or globular in shape, 4-5 microns long, 3-4 microns wide. Not metabolic. As in Bodo, it has a small rostrum in the anterior end, behind which two flagella insert. The posterior flagellum trails posteriorly, while the active flagellum bends slightly ventrally.

Cryothecomonas (cry-oh-theek-oh-moan-ass) is a medium-sized heterotrophic flagellate with two similar flagella emerging from a point just behind the apex of the cell. The ventral surface is grooved (and this causes a slight indentation at the front of the cell). Pseudopodia may arise from the ventral groove. They consume diatoms and other detritus. DIfferential interference microscopy.

Cryothecomonas (cry-oh-theek-oh-moan-ass) is a medium-sized heterotrophic flagellate with two similar flagella emerging from a point just behind the apex of the cell. The ventral surface is grooved (and this causes a slight indentation at the front of the cell). Pseudopodia may arise from the ventral groove. They consume diatoms and other detritus. Phase contrast microscopy.

Cryothecomonas (cry-oh-theek-oh-moan-ass) is a medium-sized heterotrophic flagellate with two similar flagella emerging from a point just behind the apex of the cell. The ventral surface is grooved (and this causes a slight indentation at the front of the cell). Pseudopodia may arise from the ventral groove. They consume diatoms and other detritus. Phase contrast microscopy.

Cryothecomonas aestivalis Drebes et al., 1996. Colourless flagellates, in the free, motile stage, oblong to oval, 9-12 microns long and 4-5 microns wide, two apically inserted flagella, anteriorly directed flagellum 15 microns long, posteriorly directed flagellum up to 25 microns Feeds on the marine planktonic diatom Guinardia delicatula. Flagellate penetrates the diatom frustule. Trophonts gradually phagocytize the host cytoplasm by means of a pseudopodium, which emerges posteriorly through a gap in the theca. Theca delicate, consisting of two layers, occasionally lacking. Trophonts and division stages with shortened, in part basally thickened flagella. Mature trophonts give rise to 8-32 new flagellates (swarmers). Defecation before the last division.

Discocelis (disco-see-liss) saleuta V+rs, 1988. Cells are about 3.5 - 6.5 microns long, disc-shaped, flattened, anteriorly concave and posteriorly convex. Two flagella emerge from a depression on the anterior margin of the cell. The recurrent flagellum trails behind the gliding cell and is slightly longer than the cell. The shorter flagellum is less than 1 microns long, is hard to see and is inactive. The nucleus is located anteriorly in the right half of the cell. There is a line of bodies around the margin of the cell. The cells glide smoothly in closely contact with the substrate.

Discocelis saleuta Voers, 1988. Cells are about 3.5 - 6.5 microns long, disc-shaped, flattened, anteriorly concave and posteriorly convex. Two flagella emerge from a depression on the anterior margin of the cell. The recurrent flagellum trails behind the gliding cell and is slightly longer than the cell. The shorter flagellum is less than 1 microns long, is hard to see and is inactive. The nucleus is located anteriorly in the right half of the cell. The cells glide smoothly in closely contact with the substrate.

Small gliding flagellate with one long trailing flagellum and one short one. Phase contrast microscopy.

Kiitoksia kaloista Tong et al., 1997. Small spherical gliding cells with a near spherical body measuring 2- 4 microns in diameter. Two flagella insert about a third of the way up the cell and are directed backwards during gliding. One flagellum is about twice the cell length. The other is about half the cell length or shorter. The short flagellum is difficult to see using light microscopy and could possibly be overlooked. Gliding is smooth, with the cell and long flagellum applied to the substratum. Cells sometimes waggle slightly from side to side.

Kiitoksia (kee-tox-ee-a) is a very small gliding flagellate with a rounded cell body and a single long flagellum which trails behind the gliding cell. From marine habitats. Two species - Kiitoksia ystava and K. kaloista (which in Finnish means, - Thank you my old friend, and - Thank you for the fish. Phase contrast.

Kiitoksia ystava V+rs, 1992. Cell circular or slightly reniform, 2-3 microns A single flagellum, about twice cell length, inserts into a small dent to one side of the posterior surface. A fine hair-like portion is sometimes seen at the distal end of the flagellum. Cells glide rapidly and jerkily, with the cell nodding up and down from the surface. Seen occasionally in cultures, associated with detrital flocs.

Metopion (met-ope-ee-on) fluens Larsen and Patterson, 1990. Cell outline is ovate. Cells are 4 to 9 microns long, laterally compressed and with a small rostrum anterior to the flagellar insertion. Small bodies are seen in the protrusion or at the proximal anterior part of the cell. Two flagella of unequal size emerge from a ventral groove located in the left side of the cell. The long flagellum is about 1.5 times cell length, is thickened and is not tapered at the tip, and the short flagellum may be difficult to see. There are small granules in the posterior part of the cell. The nucleus is situated near the groove. The cells move by gliding. Rarely observed.

Metopion fluens Larsen and Patterson, 1990. The cell outline is ovate. Cells are 4 to 9 microns long, laterally compressed and with a small rostrum anterior to the flagellar insertion. Small bodies are seen in the protrusion or at the proximal anterior part of the cell. Two flagella of unequal size emerge from a ventral groove located in the left side of the cell. The long flagellum is about 1.5 times cell length, is thickened and is not tapered at the tip, and the short flagellum may be difficult to see. There are small granules in the posterior part of the cell. The nucleus is situated near the groove. The cells move by gliding.

Metromonas (met-row-moan-ass) is a predator. Usually attached to the substrate by the curving posterior end of the longer flagellum (see, there is also a short one in most cells). They nod backwards and forwards. In cultures they usually appear in large numbers after the small bacterivorous flagellates - evidently preying upon them. Prey are ingested after encountering the margins of the cell. Unhappy cells tend to migrate by gliding along the substrate, with the flagellum no longer coiled but trailing behind the cells. Phase contrast

Metromonas (met-row-moan-ass) is a predator. Usually attached to the substrate by the curving posterior end of the longer flagellum (see, there is also a short one in most cells). They nod backwards and forwards. In cultures they usually appear in large numbers after the small bacterivorous flagellates - evidently preying upon them. Prey are ingested after encountering the margins of the cell. There are thin cylindrical structures near the margin - which we may assume to be associated with the capture of food. Unhappy cells tend to migrate by gliding along the substrate, with the flagellum no longer coiled but trailing behind the cells. Phase contrast

Metromonas (met-row-moan-ass) is a predator. Usually attached to the substrate by the curving posterior end of the longer flagellum (see, there is also a short one in most cells). They nod backwards and forwards. In cultures they usually appear in large numbers after the small bacterivorous flagellates - evidently preying upon them. Prey are ingested after encountering the margins of the cell. Unhappy cells tend to migrate by gliding along the substrate, with the flagellum no longer coiled but trailing behind the cells. Phase contrast

Metromonas (met-row-moan-ass) grandis Larsen and Patterson, 1990. Cell outline is leaf shaped or slightly roundish. Cells are 5 to 11 microns long (mostly 7 to 10 microns), 4 to 10 microns wide, about 2 microns deep and dorso-ventrally flattened. One side of the cell appears folded. The cells have two flagella, a long flagellum is 1.2 to 2.5 times the length of the cell and trails behind the cell when gliding. There is a short inactive flagellum, less than 2 microns long, which inserts to the right of the major flagellum and is always present. The cells attach to the substratum with the longer flagellum and move with a nodding action - like a pendulum. The nucleus is near the flagellar insertion. Relatively common.

Metromonas grandis Larsen and Patterson, 1990. Cell outline is leaf shaped or slightly roundish. Cells are 5 to 11 microns long (mostly 7 to 10 microns), 4 to 10 microns wide, about 2 microns deep and dorso-ventrally flattened. One side of the cell appears folded. The cells have two flagella, a long flagellum is 1.2 to 2.5 times the length of the cell and trails behind the cell when gliding. There is a short inactive flagellum, less than 2 microns long, which inserts to the right of the major flagellum and is always present. The cells attach to the substratum with the longer flagellum and move with a nodding action - like a pendulum. The nucleus is near the flagellar insertion.

Metromonas (met-row-moan-ass) simplex (Griessmann, 1913) Larsen and Patterson, 1990. Cells are obovate, 3 to 8 microns long (mostly 4 to 7 microns), 2 to 6 microns wide and dorso-ventrally flattened, and have smooth pellicle. The abflagellar margin of the cell is thicker than the (posterior) margin. Two flagella of very unequal length arise from the posterior part of the cell. The major flagellum is always present, is about 1.5 to 3.0 times the length of the cell and may be attached to the substrate. The short inactive flagellum is about 1 microns long and inserts to the right of the major flagellum. It may be difficult to see. The cells normally attach to the substratum and swing from side to side like a pendulum and the cells may also glide with the cell body in front of the flagellum. More common than M. grandis.

Metromonas simplex (Griessmann, 1913) Larsen and Patterson, 1990. Cells are obovate, 3 to 8 microns long (mostly 4 to 7 microns), 2 to 6 microns wide and dorso-ventrally flattened, and have smooth pellicle. The margin of the cell that is away from the flagella is thicker than the (posterior) margin. Two flagella of very unequal length arise from the posterior part of the cell. The major flagellum is always present, is about 1.5 to 3.0 times the length of the cell and may be attached to the substrate. The short inactive flagellum is about 1 microns long and inserts to the right of the major flagellum. It may be difficult to see. The cells normally attach to the substratum and swing from side to side like a pendulum and the cells may also glide with the cell body in front of the flagellum.

This is a long exposure phase contrast micrograph of Metromonas simplex in situ. This is one of my all time favourites as it so effectively captures the movements of this distinctive predator. Attaching by the crook of the long flagellum, the cell swings actively in an arc - increasing the probability of encountering another protist - its food.