Paraphysomonadaceae

Paraphysomonas (para-fie-sew-moan-ass) a heterotrophic stramenopile (related to Ochromonas and organisms traditionally referred to as chrysophytes). It is distinguished because the body surface is coated with a fine layer of scales, although in most species (this one is an exception) the scales cannot be seen with the light microscope. There are two flagella, a long one with hairs (the hair are not visible with the light microscope) but which beats with an undulating motion and draws fluid and suspended food particles to the surface of the cell. They are voracious. Phase contrast.

Paraphysomonas (para-fie-sew-moan-ass) a heterotrophic stramenopile (related to Ochromonas and organisms traditionally referred to as chrysophytes). It is distinguished because the body surface is coated with a fine layer of scales, although in most species (this one is an exception) the scales cannot be seen with the light microscope. There are two flagella, a long one with hairs (the hairs are not visible with the light microscope) but which beats with an undulating motion and draws fluid and suspended food particles to the surface of the cell. They are voracious, and this one has ingested a diatom many times larger than itself. Phase contrast.

Paraphysomonas (para-fie-sew-moan-ass) a heterotrophic stramenopile (related to Ochromonas and organisms traditionally referred to as chrysophytes). It is distinguished because the body surface is coated with a fine layer of scales, although in most species (this one is an exception) the scales cannot be seen with the light microscope. There are two flagella, a long one with hairs (the hair are not visible with the light microscope) but which beats with an undulating motion and draws fluid and suspended food particles to the surface of the cell. They are voracious. Phase contrast.

Paraphysomonas (para-fie-sew-moan-ass) a heterotrophic stramenopile (related to Ochromonas and organisms traditionally referred to as chrysophytes). It is distinguished because the body surface is coated with a fine layer of scales, although in most species (this one is an exception) the scales cannot be seen with the light microscope. There are two flagella, a long one with hairs (the hair are not visible with the light microscope) but which beats with an undulating motion and draws fluid and suspended food particles to the surface of the cell. This photograph was taken with a lengthened exposure, and the envelope of the flagellar beat is visible. Phase contrast.

Paraphysomonas (para-fie-sew-moan-ass) a heterotrophic stramenopile (related to Ochromonas and organisms traditionally referred to as chrysophytes). It is distinguished because the body surface is coated with a fine layer of scales, although in most species (this one is an exception) the scales cannot be seen with the light microscope. There are two flagella, a long one with hairs (the hair are not visible with the light microscope) but which beats with an undulating motion and draws fluid and suspended food particles to the surface of the cell. Phase contrast.

Paraphysomonas (para-fie-sew-moan-ass) a heterotrophic stramenopile (related to Ochromonas and organisms traditionally referred to as chrysophytes). It is distinguished because the body surface is coated with a fine layer of scales, although in most species (this one is an exception) the scales cannot be seen with the light microscope. There are two flagella, a long one with hairs (the hair are not visible with the light microscope) but which beats with an undulating motion and draws fluid and suspended food particles to the surface of the cell. Phase contrast.

Paraphysomonas, a colourless stramenopile flagellate. With one long flagellum that draws fluid towards the cell, and one short flagellum. Usually consumes bacteria. Body with layer of fine scales and spines. From Lake Donghu, China. Phase contrast micrograph.

Transmission electron micrograph of a whole mount showing the short naked recurrent flagellum and the longer mastigonemate flagellum. The body is coated in small organic scales. Image by D. J. Patterson.

Paraphysomonas vestita (Stokes, 1885) De Saedeleer, 1929. Ovoid to elongate cells, from 6 to 15 microns long. Two flagella insert in an apical depression. One flagellum is very short and held laterally while the other, two to three times the length of the cell, is held anteriorly and beats with short wavelength and high amplitude wave pattern. Cells often contain granules. Scales are visible in light microscopy as delicate spines. In electron microscopy, the scales have a plain circular base (1-2 microns) with a well-marked rim and a tapering spine 3 to 5 microns long.

Detail of spine scales of Paraphysomonas vestita a colourless stramenopile flagellate. This is the type species for the genus. About 50 species are recognized. . Radiating endogenous siliceous spine scales (seen here) cover the cell surface. Scale morphology (by EM) is species specific. Most Paraphysomonas species have spine scales of a single morphology but some species have 2 or 3 different types. These pushpin-shaped spine scales of P. vestita have imperforate circular base-plates by EM. The scales persist in sediments for months, providing a tool for population studies. From standing freshwater near Boise, Idaho. DIC optics.

Portrait of Paraphysomonas vestita, a colourless stramenopile flagellate. This is the type species for the genus. About 50 species are recognized. Swims freely but may attach to substrate by thin posterior stalk. The body is spherical, pyriform or ovoid. There are two flagella (visible but slightly out of focal plane here), one longer with tripartite hairs and a short less active one, which is smooth. The slightly eccentric nucleus is seen here. A single contractile vacuole is seen here. Stigma absent. Radiating endogenous siliceous spine scales (seen here) cover the cell surface. Scale morphology (by EM) is species specific. Most Paraphysomonas species have spine scales of one morphology but some species have 2 or 3 different types. Cells consume bacteria, diatoms and algae. From standing freshwater near Boise, Idaho. DIC optics.

Paraphysomonas butcheri Pennick and Clarke, 1972. As for all Paraphysomonas species, the cell has one long and one short flagellum. The surface of the cell is covered with two types of scales. Plate scales are elliptical or occasionally circular, 0.4-0.7 x 0.3-0.45 microns, with numerous circular perforations. Crown scales have a proximal ring connected to a distal arched ring by a number of struts. Scale only is illustrated.

Single cell, fixed with osmikum vapor and imaged using a transmission electron microscope. The cell is coated in small scales. There are two flagella, the longer one is coated with (tripartite) hairs that help draw food (bacteria, two of which lie beside the flagellum) into the cell.

Transmission electron micrograph of whole cell showing the surface scales.

This transmission electron micrograph of a whole mount cell shows the hairs associated with the flagellum. The hairs have three parts, a flimsy looking basal section that attaches to the flagellum, a long stiff section that then ends in fine hairs. This arrangement is synapomorphic for the stramenopiles.

Paraphysomonas corbidifera Pennick and Clarke, 1973. Cells motile, usually spherical, 2-3.25 microns in diameter. Two unequal flagella, one 2.5-3.0 times the cell body diameter in length, with two opposite rows of mastigonemes, each ending in a single fine filament, the other flagellum smooth, 2-2.5 microns in length. Cell body covered in numerous scales visible only under the electron microscope. Scales of one basic form, three-dimensional, open crown-like structures consisting of a basal ring 0.55 microns in diameter, connected by 5 or 6 equally spaced perpendicular rods, 0.125-0.15 microns long, to an apical ring. On the apical ring, halfway between each of these vertical rods, arise short horizontal rods supporting a central polygonal structure subdivided into further polygonal apertures. Cells colourless, nutrition phagotrophic. Reproduction asexual by binary fission. Image is of surface scale.

Paraphysomonas foraminifera Lucas, 1967. Motile cells, ovoid to subovoid 3.8 microns (range 3.1-4.4 microns) in diameter. Two unequal flagella, the longer 3-5 times the body diameter in length and bearing hairs approximately 1.5 microns long, these having terminal filaments 0.3-0.5 microns in length (the hairs are not visible by light microscopy), the shorter smooth and equal in length to the body diameter, coating of scales thin but with numerous scales observable only with the electron microscope, each scale consisting of a disc approximately 1 microns (0.97-1.12 microns) in diameter, perforated by about eight concentric rings of pores and with a central spine 1.5 microns (1.46-1.63 microns) in length. The spine is approximately 0.06 microns in diameter for 1/3 to1/2 of its length and then gradually tapers to a point. Cell uninucleate without a stigma or chloroplasts and containing oil and leucosin as storage materials. Nutrition phagotrophic. Asexual reproduction by simple fission into daughter cells of equal or unequal size.