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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Apogromia

Class Granuloreticulosea: Order Monothalamida: Family Microgromiidae: Subfamily Monostomiinae, tribus Microgromiini. (ref. ID; 4684)

[ref. ID; 4684]
Two genera belonging to the tribus Microgromiini are known: Microgromia and Apogromia. The newly described species corresponds to the diagnosis of the genus Apogromia, which is characterized by absence of a septum and symmetrical position of the pseudopodial stalk (Pseudopodienstiel). The pseudopodial stalk is a cytoplasmic bridge that connects the main cell mass and the pseudopodia. In the genus Microgromia the pseudopodial stalk is in an asymetrical position, because the septum in the test partly blocks the aperture. In the genus Apogromia, where the septum is absent, the aperture is free, and the pseudopodial stalk is located symmetrically in line with to the longitudinal axis of the test. It should be noted that in the genus Microgromia the asymmetrical position of the pseudopodial stalk is retained even if for some reason the septum is not developed. Such a case was observed by de Saedeleer by the species M. longisaepimen. On the other hand, the pseudopodial stalk in species of the genus Apogromia is not always distinctly developed or is very thin. In the new species the bundle of pseudopodia is extended directly from the main cell mass, which at its narrowed pole is in contact with the test in the oral region and penetrates to the oral collarette. (ref. ID; 4684)

[ref. ID; 5694]
Amoeboid protists. (ref. ID; 5694)
  1. Apogromia flandriensis (ref. ID; 4684)
  2. Apogromia lemercieri (ref. ID; 4684)
  3. Apogromia musicola (Archer, 1877) de Saedeleer (ref. ID; 4684)
    Syn; Microgromia musicola Archer, 1877 (ref. ID; 4684)
  4. Apogromia pagei Ertl, 1984 (ref. ID; 4684 original paper)
  5. Apogromia verbrugghei (ref. ID; 4684)

Apogromia pagei Ertl, 1984 (ref. ID; 4684 original paper)

Descriptions

Test is hyaline or finely granular, transparent, yellow or sometimes pale-brownish, rarely dark brown. The most frequent form of the test is globular or broadly bell-shaped, on the one pole flattened or moderately concave. In this pole of the test is an aperture prolonged as a short tube. In optical section the test wall has a more or less wavy contour. The protoplast is pear-shaped, with its elongated pole toward the aperture. From this pole fine pseudopodia are extended. The protoplast does not fill the test completely. It is connected to the test in or near the oral tube. Only rarely were epipodia observed. The large vesicular nucleus, situated near the aboral end of the cell, ranged in diameter from 6-7 um. The cytoplasm contains a fair number of coarse, clear granules, but specimens without such granules were also observed. The single contractile vacuole is located in the oral region of the protoplast. Division takes place within the test. Two daughter cells were sometimes observed in a test. Details of division are not yet known. The pseudopodia are extremely thin, so that it is difficult to follow them along the whole length. They are extended in the form of a broad cone. Each pseudopodium has two or three small granules. The number of pseudopodia varies from 10-20 or more, and their length reaches 40-50 um. Only exceptionally do pseudopodia anastomose. (ref. ID; 4684)

Type locality

Backwater of the River Danube. (ref. ID; 4684)

Measurements

Size of the tests: diameter of test 28-30 um, diameter of apertures 5.5-7.5 um, length of oral collarette 4-5.5 um. (ref. ID; 4684)