Watch glass
| Watch glass | ||||||||||||
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Watch glass ( Arcella ) |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Arcella | ||||||||||||
| Ehrenberg , 1832 |
The watch glasses ( Arcella ), also watch glass animals or watch glass animals , are a genus of the Arcellinida .
features
Like all shell amoebas, they have a non-chambered housing made of a structural substance made of organic material (structural proteins). In contrast to other types, no pebbles or other foreign bodies are installed to reinforce the housing. The bowl-like case is reminiscent of a watch glass. The case has a diameter of up to 0.17 mm and a height of up to 0.07 mm. When viewed under the microscope, this housing usually appears round with a central opening. The brownish color of the domed shells is caused by the accumulation of iron and manganese compounds, which increases with age.
Most species have two cell nuclei, some more, the large-mouthed clock glass animal ( Arcella megastoma ) has up to 200. There are several contractile vacuoles . The cell is anchored to the housing wall, but does not completely fill the housing. The cysts are round and located inside the case.
distribution
The protozoa live worldwide in fresh water, also in eutrophic waters, in bogs or even on wet leaves. They are also found in wet and dry mosses, a few species also live terrestrially. They feed mostly herbivorous .
Systematics and types (selection)
Type species is the common clock glass animal ( Arcella vulgaris ). Filled fossils belonging to the genus Arcella have been known since the Paleozoic and were found, for example, in the coal of the Ruhr area . Extant currently about 50 species and numerous varieties and forms are known, including:
- Common clock glass animal ( Arcella vulgaris )
- Humped clock glass animal ( Arcella gibbosa )
- Arcella hemisphaerica
- Pyramid clock glass animal ( Arcella conica )
- Toothed clock glass animal ( Arcella dentata )
- Plate clock glass animal ( Arcella artocrea )
- Disc clock-glass animal ( Arcella discoides )
- Loud-mouthed clock -glass animal ( Arcella megastoma )
proof
- ↑ a b c Heinz Streble , Dieter Krauter : Life in the water drop. Microflora and microfauna of freshwater. An identification book. 3. Edition. Franckh, Stuttgart 1976, ISBN 3-440-04000-3 , p. 222.
- ↑ a b c d Ralf Meisterfeld: Arcellinida In: John J. Lee, GF Leedale, P. Bradbury (Ed.): An Illustrated Guide to the Protozoa . tape 2 . Allen, Lawrence 2000, ISBN 1-891276-23-9 , pp. 834-835 .
