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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Pelomyxa

Pelomyxa Greeff, 1874 (ref. ID; 3652, 3687)

[ref. ID; 1618]
Large amoeboid organisms, ranging from 0.5 to 4 or 5 mm in length when clavate and moving progressively; nuclei numerous less than 100 to 1000 or more; many small contractile vacuoles; refringent bodies of various dimension and number; with or without bacterial inclusions (which Penard and others consider as symbiotic); holozoic on plant or animal organisms or detritus; plasmotomy simple or multiple; in fresh water. (ref. ID; 1618)

[ref. ID; 1923]
Large amoebae with indeterminate pseudopods directing locomotion. Many nuclei; body usually enclosing symbiotic bacteria. Many species. Modern authors tend to consider as Pelomyxa the large or medium-sized amoebae showing a fixed polarity, with a single anterior pseudopod and a posterior urosphaera (=spherical zone ending the body, often provided with a tuft of very delicate pseudopods). (ref. ID; 1923)

[ref. ID; 3652]
A genus containing one species, P. palustris, a giant multinucleate amoeboid flagellate with three kinds of cytoplasmic bacteria (oxidative, glycolytic, methanogenic) often adhering to nuclei; many nonmotile flagella; many microtubules. Life cycles includes cysts. (ref. ID; 3652)
  1. Pelomyxa badia Lepsi, 1960 (ref. ID; 3687 original paper)
  2. Pelomyxa belevskii Penard, 1893 (ref. ID; 3687, 3693)
  3. Pelomyxa (Amoeba) binucleata (Gruber, 1885) (ref. ID; 3687) or (Gruber) Penard, 1902 (ref. ID; 3693 redescribed paper)
    Syn; Amoeba binnucleata Gruber (ref. ID; 3693)
  4. Pelomyxa carolinensis Wilson, 1900 (ref. ID; 3687) reported year? (ref. ID; 1618, 1923)
  5. Pelomyxa caulleryi (ref. ID; 3652)
  6. Pelomyxa fragilis Penard, 1904 (ref. ID; 3687)
  7. Pelomyxa illinoisensis Kudo (ref. ID; 1618, 1923)
  8. Pelomyxa laureata Penard (ref. ID; 1923)
  9. Pelomyxa nobilis Penard (ref. ID; 1923)
  10. Pelomyxa palustris Greeff, 1874 (ref. ID; 3652, 3665, 3687) reported year? (ref. ID; 1618, 1923, 3693) reported author and year? (ref. ID; 3292, 3946, 4672)
    Syn; Pelomyxa villosa Leidy (ref. ID; 1618)
  11. Pelomyxa paradoxa Penard, 1902 (ref. ID; 3687, 3693 original paper)
  12. Pelomyxa parvialveolata Korotneff, 1879 (ref. ID; 3687)
  13. Pelomyxa (Amoeba) prima (Gruber, 1885) (ref. ID; 3687) or (Gruber) Penard, 1902 (ref. ID; 3693 redescribed paper)
    Syn; Amoeba prima Gruber (ref. ID; 3693)
  14. Pelomyxa (Amoeba) quarta (Gruber, 1885) (ref. ID; 3687)
  15. Pelomyxa (Amoeba) quinta (Gruber, 1885) (ref. ID; 3687)
  16. Pelomyxa (Amoeba) secunda (Gruber, 1885) (ref. ID; 3687)
  17. Pelomyxa tarda Gruber, 1886 (ref. ID; 3687)
  18. Pelomyxa tertia (Gruber, 1885) (ref. ID; 3687) or (Gruber) Penard, 1902 (ref. ID; 3693 redescribed paper)
    Syn; Amoeba tertia Gruber (ref. ID; 3693)
  19. Pelomyxa villosa Leidy, 1879 (ref. ID; 3687) reported year? (ref. ID; 1618)
    See; Pelomyxa palustris (ref. ID; 1618)
  20. Pelomyxa viridis Bourne, 1891 (ref. ID; 3687)
  21. Pelomyxa vivipara Penard, 1902 (ref. ID; 3687, 3693 original paper) reported year? (ref. ID; 1923)

Pelomyxa carolinensis Wilson, 1900 (ref. ID; 3687) reported year? (ref. ID; 1618, 1923)

Descriptions

Locomotion active; nuclei up to 1000 or more, circular in front view, about 20 um in diameter and ellipsoid in profile; fluid and food vacuoles, crystals, many contractile vacuoles; feeds on various protozoa and invertebrates; easily cultivated in laboratory; plasmotomy into 2-6 individuals; nuclear division simultaneous and synchronous. (ref. ID; 1618)
Without symbiotic bacteria. (ref. ID; 1923)

Measurements

Monopodal forms 1-5 mm long; polypodal forms 1-2 mm in diameter. (ref. ID; 1618)

Pelomyxa caulleryi (ref. ID; 3652)

Descriptions

Pelomyxa caulleryi recognized as a recently excysted form of P. palustris. (ref. ID; 3652)

Pelomyxa illinoisensis Kudo (ref. ID; 1618, 1923)

Descriptions

The organism resembles P. carolinensis, but much smaller in size; several hundred nuclei, spherical, 14-16 um in diameter; peripheral granules of the nuclei are large and often discoid, irregularly distributed; crystals occur abundantly in all physiological conditions; chalky white in reflected light; plasmotomy into 2-5 daughters; encystment and excystment take place freely in cultures; cysts with usually 2 membranes, a multinucleate amoeba emerges from a cyst after several weeks. (ref. ID; 1618)

Measurements

500-1000 um in length; clavate forms seldom 1.5 mm; cyst 250-350 in diameter. (ref. ID; 1618)

Pelomyxa laureata Penard (ref. ID; 1923)

Descriptions

Without symbiotic bacteria. (ref. ID; 1923)

Pelomyxa palustris Greeff, 1874 (ref. ID; 3652, 3665, 3687) reported year? (ref. ID; 1618, 1923, 3693) reported author and year? (ref. ID; 3292, 3946, 4672)

Synonym

Pelomyxa villosa Leidy (ref. ID; 1618)

Description

Large; sluggish, with usually one broad pseudopodium; undifferentiated cytoplasm with many nuclei and various inclusions such as fragments of plant bodies, numerous small sand particles, etc., which brings about opacity and dark coloration of body; in addition bacteria (Cladothrix pelomyxae Veley, Myxococcus pelomyxae Keller and Bacterium parapelomyxae Keller) occur in the cytoplasm which some observers consider as symbionts; cyst with 2-3 envelopes; feeds on plant and inorganic debris; polysaprobic in still stagnant water, buried in mud. (ref. ID; 1618)
Nuclei numerous. Endoplasm enclosing sand, brilliant corpuscles and bacteria simple and double rod. Habitat ooze of ponds, water with putrefying leaves, sphagnous swamps. (ref. ID; 1923)
The giant amoeba Pelomyxa palustris is a peculiar eukaryotic organism. It lacks Golgi-bodies, mitochondria, a mitotic apparatus, and any "9+2" organelle. Pelomyxa is a multinucleate herbivorous organism. (ref. ID; 3665)

Measurements

2-3 mm, or larger in diameter. (ref. ID; 1618)