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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Platycola

Platycola Kent, 1881 (ref. ID; 1248) or 1882 (ref. ID; 2014)

Class Oligohymenophora: Subclass Peritricha: Order Peritrichida: Suborder Sessilina (ref. ID; 2014)
Family Vaginicolidae Kent, 1881 (ref. ID; 1248)

[ref. ID; 2014]
Body trumpet-shaped lying within a horizontal pseudochitinous lorica to which it is attached at the posterior end. The lorica adheres along the length of one side to algae and other submerged objects by a dark sticky substance. It has a simple oval aperture, without valves etc., and is turned up diagonally so that the extended animal may protrude upwards. The genus may be most easily confused with Lagenophrys which also has a lorica lying horizontally. However, in the latter genus there is a complicated valve system to close the aperture and the animal is anchored laterally to the lorica.
Quote; Colin R. Curds, Michael A. Gates and David McL. Roberts "British and other freshwater ciliated protozoa Part II Ciliophora: Oligohymenophora and Polyhymenophora" Cambridge University Press, 1983 (ref. ID; 2014)
  1. Platycola amphora Swarczewsky, 1930 (ref. ID; 1620)
  2. Platycola amphoroides Sommer, 1951 (ref. ID; 1248 original paper)
  3. Platycola ampulla Fromentel, 1874 (ref. ID; 1620)
  4. Platycola baicalica Swarczewsky, 1930 (ref. ID; 1620)
  5. Platycola butschlii Nusslin, 1884 (ref. ID; 1620) reported author and year? (ref. ID; 7653)
  6. Platycola coelochila Stokes, 1887 (ref. ID; 1620)
  7. Platycola decumbens Ehrenberg, 1830 (ref. ID; 1557, 1620, 1629, 7690) or (Ehrenberg, 1830) Kent, 1882 (ref. ID; 4610)
    Syn; Vaginicola decumbus Ehrenberg, 1830 (ref. ID; 4610); Vaginicola truncata Fromentel, 1876 (ref. ID; 4610)
  8. Platycola dilatata Fromentel, 1874 (ref. ID; 1620)
  9. Platycola donsi Kahl, 1933 (ref. ID; 1620)
    Syn; Platycola dilatata Dons, 1922 (ref. ID; 1620)
  10. Platycola gracilis Fromentel, 1874 (ref. ID; 1620)
  11. Platycola hydrobiae Hofker, 1930 (ref. ID; 1620)
  12. Platycola intermedia Kellicott, 1884 (ref. ID; 1620)
  13. Platycola intermedia Maskell, 1887 (ref. ID; 1620)
  14. Platycola longicollis Kent, 1881 (ref. ID; 1335, 1557, 1620) reported year? (ref. ID; 1618)
  15. Platycola mollis Fromentel, 1874 (ref. ID; 1620)
  16. Platycola nigra Wailes, 1928 (ref. ID; 1620)
  17. Platycola pala Swarczewsky, 1930 (ref. ID; 1620)
  18. Platycola reflexa Mermod (ref. ID; 1620)
  19. Platycola regularis Fromentel, 1874 (ref. ID; 1620) reported author and year? (ref. ID; 7653)
  20. Platycola steineri Penard, 1914 (ref. ID; 1620)
  21. Platycola striata Fromentel, 1874 (ref. ID; 1557, 1620)
  22. Platycola tincta Fromentel, 1874 (ref. ID; 1620)
  23. Platycola truncata Fromentel, 1874 (ref. ID; 1219, 1557, 1620, 2245) reported year? (ref. ID; 3343, 5462) reported author and year? (ref. ID; 191, 7653)
    Syn; Platycola striata Kralik, 1961

Platycola decumbens Ehrenberg, 1830 (ref. ID; 1557, 1620, 1629, 7690) or (Ehrenberg, 1830) Kent, 1882 (ref. ID; 4610)

Synonym

Vaginicola decumbus Ehrenberg, 1830 (ref. ID; 4610); Vaginicola truncata Fromentel, 1876 (ref. ID; 4610)

Descriptions

The lorica of P. decumbens was colourless or pale yellow in young cells and was seen to gradually turn brown with age. It was usually seen to be roughly rectangular with rounded corners or slightly oval in shape. Lorica size vareid considerably, ranging from 65-145 um in length (mean 96 um) and 44-110 um in width (mean 75 um). The lorica usually lay decumbent with the whole of its ventral wall in contrast with the substrate. The dorsal wall was slightly convex, with the central region frequently flattened slightly to form a plateau. The dorsal wall appeared smooth when viewed with the light microscope, but some specimens were observed to have several closely spaced ridges in the anterior region, or occasionally over the whole lorica. A slit-like aperture was present at the anterior end of the lorica, through which the zooids projected, it varied in width from 35-50 um. The aperture was held pointing forwards and upwards, frequently at the end of a short broad neck, its rim was always folded back to form a single continuous lip. Around the lorica there was a broder fringe that was seen as a flat rim with an irregular wavy outline, and extended over the substrate from the edge of the lorica to a distance of up to 5 um. The vast majority of specimens isolated, were covered to varying degrees with organisms of the 'aufwuchs' community including diatoms, bacteria and fungi. Two zooids were usually present in each lorica, which were commonly seen to extend well beyond the aperture and were usually held in a vertical position. The zooids were striated with one contractile vacuole near the peristome and a long straight macronucleus situated longitudinally in the body. Each zooid was affixed by its posterior end without the use of a stalk, a similar arrangement to that observed in the genus Lagenophrys Stein, 1851. This is in contrast to other loricate genera such as Thuricola Kent, 1881, in which the zooid was found to be attached via a short stalk within the lorica, and Pyxicola Kent, 1882, where the whole lorica itself is held on a stalk. However it is not known whether the zooids of Platycola attach directly to the substrate itself or to the ventral wall of the lorica. (ref. ID; 7690)

Examined materials

P. decumbens were collected from the River Tillingbourne, a clean shallow river, at Shalford, Surrey, England, National Grid reference TQ999479 between April and March 1981. (ref. ID; 7690)

Platycola longicollis Kent, 1881 (ref. ID; 1335, 1557, 1620) reported year? (ref. ID; 1618)

Descriptions

Lorica yellow to brown when older; fresh water. (ref. ID; 1618)

Measurements

Lorica about 126 um long. (ref. ID; 1618)

Platycola truncata Fromentel, 1874 (ref. ID; 1219, 1557, 1620, 2245) reported year? (ref. ID; 3343, 5462) reported author and year? (ref. ID; 191, 7653)

Synonym

Platycola striata Kralik, 1961

Descriptions

Lorica always recumbent and attached by the flat side to the substrate; the lorica always shows a small neck-like opening in the anterior region and is fastened to the substrate by a characteristic darkish, cementing edge, which is clearly seen in the ventral view; outline of lorica, shape of neck, etc. may vary greatly; older loricae are more or less covered by brownish Fe(OH)3. Body of the ciliate fixed to the posterior end of the lorica; the elongated cylindrical body may be extended beyond the lorica; 1 band-like macronucleus; a single micronucleus; contractile vacuole near the buccal cavity; usually there are 2 individuals in the lorica, often only 1 an sometimes 3 or more; sometimes an empty lorica may be colonized by Chaetospira muelleri or Lacrymaria olor. (ref. ID; 1219)

Measurements

Body 60-170 um, lorica 65-145 um (average 96 um). (ref. ID; 1219)
Length of lorica 125 um. (ref. ID; 3343)