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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Astrodisculus

Astrodisculus Greeff, 1869 (ref. ID; 3691) reported year? (ref. ID, 1618) or Greeff, 1869 sensu Penard, 1904 (ref. ID; 3541, 4670)

See Chlamydaster

[ref. ID; 1618]
Spherical with gelatinous envelope, free from inclusions, sometimes absent; no demarcation between two regions of the cytoplasm; pseudopodia fine without granules; fresh water. (ref. ID; 1618)

[ref. ID; 1923]
Nucleus eccentric, generally a central corpuscle from which the axial filaments arise. With a mucilaginous shell aglomerating foreign elements. Surface of the mucilagenous investment with delicate extraneous particles and bacteria. Body investment spherical, concentric. (ref. ID; 1923)
  1. Astrodisculus affinis Schouteden, 1905 (ref. ID; 3541)
  2. Astrodisculus araneiformis Schewiakoff, 1893 (ref. ID; 3541) reported year? (ref. ID; 3691)
  3. Astrodisculus laciniatus Penard, 1904 (ref. ID; 3691 original paper)
    See; Chlamydaster laciniatus (ref. ID; 3541, 4879)
  4. Astrodisculus marinus Kufferath, 1952 (ref. ID; 3541)
  5. Astrodisculus penari Roskin, 1929 (ref. ID; 3541)
  6. Astrodisculus radians Greeff (ref. ID; 1618, 1923, 3691) or Greeff, 1869 sensu Penard, 1904 nec Stern, 1924 (ref. ID; 3541, 4670)
    Syn; Heliophrys varians West (ref. ID; 3691); Heliosphaerium aster Frenzel, 1897 (ref. ID; 3541) reported year? (ref. ID; 3691)
  7. Astrodisculus radians Stern, 1924
    See; Chlamydaster sterni (ref. ID; 3541, 4879)
  8. Astrodisculus serratus Walton, 1930 (ref. ID; 3541)
  9. Astrodisculus zonatus Penard, 1904 (ref. ID; 3541, 3691 original paper)

Astrodisculus radians Greeff (ref. ID; 1618, 1923, 3691) or Greeff, 1869 sensu Penard, 1904 nec Stern, 1924 (ref. ID; 3541, 4670)

Synonym

Heliophrys varians West (ref. ID; 3691); Heliosphaerium aster Frenzel, 1897 (ref. ID; 3541) reported year? (ref. ID; 3691)

Descriptions

Outer surface usually with adherent foreign bodies and bacteria; cytoplasm often loaded with green, yellow, or brown granules; nucleus eccentric; a contractile vacuole; in pools and ditches. (ref. ID; 1618)
Very minute form with a thick, colorless mucilagenous investment. Pseudopodia not numerous, of moderate length; nucleus not large, placed eccentrically. One contractile vacuole. Habitat pools and ditches; not common. (ref. ID; 1923)

Remarks

The plasma body of this species spherical but easily deformed into an egg shape. It has a gelationus envelope with bacteria loosely distributed. The nucleus is round, eccentric, and with a nucleolus almost half filling it. The pseudopodia are filiform, hyaline and not granular (Greeff 1869; Rainer 1968). From this description the organism would appear very similar indeed to Nucleosphaerium. However, a form of locomotion which involves the lengthening and shortening of the pseudopodia was described (Rainer 1968), and similar form of locomotion described for A. zonatus Penard (Penard 1904; Rainer 1968). This form of locomotion is typical of heliozoans (Watters 1968), and modern opinion is tending to put Astrodisculus with the heliozoans, mainly due to the fact that it has an eccentric nucleus, as do the centrohelid heliozoans. (ref. ID; 4670)

Measurements

Diameter 25-30 um including envelope. (ref. ID; 1618)
Diameter 13-17 um. (ref. ID; 1923)