Centrohelid

Canencia, Madrid, Spain

Portrait of the heterophrid centroheliozoan, Chlamydaster sterni (Rainer, 1968). The external surface of the cell is coated by a thick homogeneous coat of mucous without siliceous elements. Bacteria and debris sometimes adhere to the mucous coat. The axopodia protrude through the mucous. The axopodia bear extrusomes (not seen here). There is a single contractile vacuole. The other species in this genus, C. laciniatus (Penard, 1904) is distinguished by its fimbriated mucous coat. C. sterni is planktonic in both freshwater and marine habitats. Collected from a commercial saltwater aquarium in Boise, Idaho November 2004. Phase contrast.

Lumbreras, La Rioja, Spain

Canencia, Madrid, Spain

Portrait of the heterophrid centroheliozoan, Chlamydaster sterni (Rainer, 1968). The external surface of the cell is coated by a thick homogeneous coat of mucous without siliceous elements. Bacteria and debris can be seen here adhering to the mucous coat. The axopodia protrude through the mucous. Extrusomes appear here as small beads along some of the axopodia. The contractile vacuole is seen at 9 o’clock. Several large cytoplasmic food vacuoles are visible and a small particle of food at 2 o’clock is about to be ingested. The other species in this genus, C. laciniatus (Penard, 1904) is distinguished by its fimbriated mucous coat. C. sterni is planktonic in both freshwater and marine habitats. Collected from a commercial saltwater aquarium in Boise, Idaho. DIC.

Vilobi Del Penedes, Catalonia, Spain

Heterophrys (het-err-off-riss) is a centrohelid heliozoon - the most speciose group of heliozoa. The heliozoa do not form a natural (monophyletic and holophyletic) group of protists, but a type of organization that have been arrived at from a number of different evolutionary lineages. Heterophrys is apparently naked, careful scrutiny usually reveals delicate radiating (organic) spicules. the arms terminate on a non-nuclear organizing centre (the dark dot in this cell). Heliozoa are predators, motile prey is captured after swimming into the arms. This cell seems to have been eating algae. Differential interference contrast.

Lumbreras, La Rioja, Spain

Heterophrys (het-err-off-riss) is a centrohelid heliozoon - the most speciose group of heliozoa. The heliozoa do not form a natural (monophyletic and holophyletic) group of protists, but a type of organization that have been arrived at from a number of different evolutionary lineages. Heterophrys is apparently naked, careful scrutiny usually reveals delicate radiating (organic) spicules. the arms terminate on a non-nuclear organizing centre (the dark dot in this cell. Heliozoa are predators, motile prey is captured after swimming into the arms. This cell seems to have been eating algae. Phase contrast.

Heterophrys (het-err-off-riss) is a centrohelid heliozoon - the most speciose group of heliozoa. Heterophrys is apparently naked, careful scrutiny usually reveals delicate radiating (organic) spicules. the arms terminate on a non-nuclear organizing centre (the dark dot in this cell. Heliozoa are predators, motile prey is captured after swimming into the arms - as can be seen here. Phase contrast.

Heterophrys (het-err-off-riss) is a centrohelid heliozoon, distinguished by having radially arrayed organic spicules arising from the surface of the cell. The longer rays with granules are the arms - pseudopodial extensions supported by microtubules. The arms are used to capture food. Phase contrast. Material from Nymph Creek and Nymph Lake, thermal sites within Yellowstone National Park, photograph by Kathy Sheehan and David Patterson.

Portrait of heterophrys, a small heliozoon coated in very thin organic spines. This thin axopodia contain prominent spherical extrusomes are fully extended in this image. Axopodia contract when the organism is disturbed, bunching extrusomes at the cell surface as seen in the other image. Usually described as a marine genus, these individuals were collected from an organically enriched standing freshwater pond near Boise, Idaho. Phase contrast

Portrait of Heterophrys, a centroheliozo0n with fine radial organic spicules passing through a mucus coat. Axopodia bearing extrusomes are seen in this image. Some species contain endosymbiotic algae. From freshwater pond near Boise, Idaho. Phase contrast.

Portrait of Heterophrys, a centroheliozoan with fine radial organic spicules passing through a mucous coat. Axopodia bearing extrusomes are seen in this image. Some species contain endosymbiotic algae. From freshwater pond near Boise, Idaho. Phase contrast.

Phase contrast image of living cell, thin arms used for food capture.

Transmission electron micrograph of a whole spine scale.

Transmission electron micrograph of whole spine scales and plate scales.

The picture shows the two types of actinomorphic siliceous spines (the shorter type is forked, see inset top right) and the tangential scales. Nucleus is clearly shown together with some food vacuoles.  Sample from sphagnum pond Dosenmoor near Neumuenster (Schleswig-Holstein, Germany). Images were taken using Zeiss Universal with Olympus C7070 CCD camera.

Acanthocystis turfacea (a-can-tho-sis-tis tur- fats-ee-a), a centrohelid heliozoon. Body coated with a layer of flattened siliceous scales and spine scales. Spine scales are of two lengths, and forked at their apices. This sample from moss. Nucleating site for axopodia just about evident in the cell to the right. Differential interference contrast.

Acanthocystis turfacea (a-can-tho-sis-tis tur- fats-ee-a), a centrohelid heliozoon. Body coated with a layer of flattened siliceous scales and spine scales. Spine scales are of two lengths, and forked at their apex. This sample from moss. Differential interference contrast.

Acanthocystis turfacea (a-can-tho-sis-tis tur- fats-ee-a), a centrohelid heliozoon. Body coated with a layer of flattened siliceous scales and spine scales. Spine scales are of two lengths, and forked at their apices. Axonemes terminate on central granule or centroplast, shown here. This sample from moss. Differential interference contrast.

Acanthocystis turfacea (a-can-tho-sis-tis tur- fats-ee-a), a centrohelid heliozoon. Body coated with a layer of flattened siliceous scales and spine scales. Spine scales are of two lengths, and forked at their apices. This sample from moss. Differential interference contrast.

Acanthocystis turfacea (a-can-tho-sis-tis tur- fats-ee-a), a centrohelid heliozoon. Body coated with a layer of flattened siliceous scales and spine scales. Spine scales are of two lengths, and forked at their apex. The cytoplasm of this species contains often symbiotic algae. The body of this specimen measures 88 microns in diameter. This specimen was collected in a pond near Konstanz, Germany. Differential interference contrast.