Euglenoides

Rhabdomonas spiralis (PRINGSHEIM,1942).Collected from a freshwater pond near Boise, Idaho.July 2007. DIC.

Portrait of Menoidium a colorless euglenoid flagellate. Strongly flattened. One side curved with the other more straight. One emergent flagellum. Stigma absent. Paramylon bodies are dimorphic with smaller round and larger elongate ring forms. Swims rotating on long axis. Highly refractile. From standing freshwater near Boise, Idaho. Brightfield.

Portrait of Menoidium a colorless euglenoid flagellate. Strongly flattened. One side curved with the other more straight. One emergent flagellum. Stigma absent. Paramylon bodies are dimorphic with smaller round and larger elongate ring forms. Swims rotating on long axis. From standing freshwater near Boise, Idaho. Phase contrast.

Menoidium pellucidum. Cell observed in freshwater habitats in the vicinity of Broome, Western Australia in September 2003. This image was taken using phase contrast optics.   This work was supported by the Australian Biological Resources Study.

Menoidium pellucidum. Empty pellicle observed in freshwater habitats in the vicinity of Broome, Western Australia in September 2003.  This work was supported by the Australian Biological Resources Study.

Menoidium pellucidum. Cell observed in freshwater habitats in the vicinity of Broome, Western Australia in September 2003. This image was taken using phase contrast optics.   This work was supported by the Australian Biological Resources Study.

Anisonema (a-nice-o-neme-a), heterotrophic euglenid, glides over the substrate, with an anterior flagellum sweeping in front of the cell and with a long recurrent flagellum trailing over the substrate. As is common in the euglenids, the flagella seem to be very thick - especially as we can see here the recurrent flagellum. Occasionally jerks backwards. Common in intertidal sediments. Phase contrast.

Anisonema (a-nice-o-neme-a), a genus of heterotrophic euglenids commonly found in sediments. With one flagellum sweeping from side to side in front of the cell, and with a second flagellum following a hooked curve and then trailing behind the cell. The cells may periodically jerk backwards. Body not metabolic, no mouth visible by light microscopy. Phase contrast.

Anisonema has no chloroplasts. It has two flagella. One projects from the front of the cell and sweeps from side to side, the second flagellum trails behind the cell. This euglenid was collected at Obsidian Creek.

Gliding Anisonema cell, the anterior flagellum is to the top and beats with a sweeping motion, the second flagellum adheres to the substrate and tarils behind the moving cell. Phase contrast microscopy.

Anisonema (a-nice-o-neme-a) is one of the gliding heterotrophic euglenids, common. It has a distinctive pattern of movement, moving forwards with one thicker flagellum trailing and the other flagellum extending in front and sweeping from side to side in front of the cell, and then periodically jerking backwards. This movement is associated with the strong recurrent flagellum which, as it leaves the cell, follows a curve or hook. The genus is defined in part by not having a mouth that is visible by light microscopy, but this cell has clearly been eating diatoms. Differential Interference Contrast.

Anisonema (a nice-owe-knee-ma) acinus Dujardin, 1841. Cell outline is like a grain of barley. Cells are 21 to 40 microns long, 13 to 17 microns wide, flattened with a ventral groove, which diminishes posteriorly. There are about nine longitudinal pellicular grooves on each of the ventral and dorsal faces of the cell. In some cells, the grooves are fine and difficult to see but in a few cells they are deeper. The cells have a chisel-shaped ingestion organelle, which is difficult to observe at times. The anterior flagellum is about 1.5 times cell length and beats freely from side to side. The trailing posterior flagellum is about 1.7 to 3.2 times the length of the cell, is thicker than the anterior flagellum, lies in the ventral groove, and tapers posteriorly. The cells contain diatoms up to 25 microns long and one cell had four diatoms as long as 13 microns The flagellar pocket is located in the left side of the cell and the nucleus is in the right side. The cells glide smoothly, but jerk backwards when changing direction. Commonly observed.

Anisonema acinus Dujardin, 1841. Cell outline is like a grain of barley. Cells are 21 to 40 microns long, 13 to 17 microns wide, flattened with a ventral groove, which diminishes posteriorly. There are about nine longitudinal pellicular grooves on each of the ventral and dorsal faces of the cell. In some cells, the grooves are fine and difficult to see but in a few cells they are deeper. There is debate as to whether this species has an ingestion organelle, it was described without such an organelle, in some cells no organelle is seen, but in other cells otherwise indistinguishable from mouthless cells, a mouth can be seen. The anterior flagellum is about 1.5 times cell length and beats freely from side to side. The cells may eat large particles of food, such as diatoms. The trailing posterior flagellum is about 1.7 to 3.2 times the length of the cell, is thicker than the anterior flagellum, lies in the ventral groove, and tapers posteriorly. The flagellar pocket is located in the left side of the cell and the nucleus is in the right side. The cells glide smoothly, but jerk backwards when changing direction.

Anisonema acinus. Cell observed in freshwater habitats in the vicinity of Broome, Western Australia in September 2003. This image was taken using phase contrast optics.   This work was supported by the Australian Biological Resources Study.

Heterotrophic euglenoid photographed using DIC microscopy. Isolated by M. Virginia Sanchez Puerta from Little Sippewisset Pond, Woods Hole, MA, USA in October 2005

Anisonema glaciale Larsen and Patterson, 1990. The cell body is oval or slightly ovate, 26-28 microns long, 13-14 microns wide. The cell surface has 12-15 delicate furrows. The posterior flagellum lies in a distinct gutter on the central side. Refractile bodies cluster around the base and one or both walls of the reservoir. Nucleus central. The moves forward with a rapid sleek gliding, the anterior flagellum sweeping from side to side, but may occasionally come to a complete halt for the few seconds, usually executing a reversal following the arrest.

Anisonema ovale Klebs, 1893. Cells are oval, rigid and measure 11 microns long and 7 microns wide. The cell surface is smooth. The anterior flagellum is about the cell length and the posterior one is 1.5 times the cell length. Looks like Protaspis tegere and further study may reveal that this is not really an Anisonema.

Anisonema (a-nice-o-neme-a), a genus of heterotrophic euglenids commonly found in marine sediments. With one flagellum sweeping from side to side in front of the cell, and with a second flagellum following a curve and then trailing behind the cell. Periodically the cells jerk backwards. Body not metabolic, no mouth visible by light microscopy. This species is A. trepidum, distinguished by occasionally arresting its forward movement. Differential Interference Contrast.

Anisonema (an-iceo-owe-knee-ma) trepidum, a small gliding euglenid flagellate, body stiff, with one undulating flagellum held in front of the cell, the second trailing. Every now and then, cells may come to a halt. Phase contrast micrograph.

Anisonema (a nice-owe-knee-ma) trepidum Larsen, 1987. Cells are oblong, 13 to 19 microns long, 6.5 to 10 microns wide, flattened with a chisel-shaped ingestion organelle, which is difficult to observe. There are three distinct grooves on the dorsal and ventral faces of the cell. Two emergent flagella are of unequal length. The anterior flagellum is approximately 1.5 times the cell length, and the trailing posterior flagellum is stronger than the anterior flagellum, is approximately 3.5 to 5 times cell length and tapers distally. The flagellar pocket and nucleus are in the left side of the cell. The cells contained small granules. The cells glide quickly in straight lines and jerk when changing direction. Rarely observed.

Anisonema trepidum Larsen, 1987. Cells are oblong, 13 to 19 microns long, 6.5 to 10 microns wide, flattened and may have a wedge-shaped ingestion organelle. There are three distinct grooves on the dorsal and ventral faces of the cell. The two emergent flagella are of different lengths. The anterior flagellum is approximately 1.5 times the cell length, and the trailing posterior flagellum is stronger than the anterior flagellum, is approximately 3.5 to 5 times cell length and tapers distally. The flagellar pocket and nucleus are in the left side of the cell. The cells contained small granules. The cells glide quickly in straight lines and jerk when changing direction.