Dexiostoma campyla
| Dexiostoma campyla | ||||||||||||
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| Systematics | ||||||||||||
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| Scientific name of the genus | ||||||||||||
| Dexiostoma | ||||||||||||
| Jankowski 1967 | ||||||||||||
| Scientific name of the species | ||||||||||||
| Dexiostoma campyla | ||||||||||||
| ( Stokes , 1886) Jankowski , 1967 |
Dexiostoma campyla is a protozoa that the ciliates heard and the only member of the genus Dexiostoma . The species was previously included in the genus Colpidium , but was separated from it as a genus in its own right in 1967. Dexiostoma campyla lives in bodies of water. It can be used as an indicator of the degree of pollution of a body of water.
features
Dexiostoma campyla are usually about 60 (35 to 90) micrometers long and 20 (15 to 35) micrometers wide, about three times as long as they are wide, and of slender, occasionally broad oval shape. The front end is rounded like the rear end, the latter is occasionally slightly tapered. The laterally flattened body widens from the front to the rear end.
The pre-oral area is blunt on one side and has a slightly oval, non-lashed section. The proral suture is straight and not twisted (twisted), lies almost in the middle and slightly shifted to the left. The first membranelle consists almost entirely of a single row of kinetosomes , the short third consists of three rows of kinetosomes.
The cells have 16 to 33 somakinetes , with those on the right side being significantly less curved than in the genera Colpidium and Paracolpidium . The kinets on the right side do not or hardly point over to the left side in the pre-oral area and also reach closer to the front end than the kinets on the left side. The distance between kinets 2 and 3 is slightly larger in the proral area. The two-ended kinets, which are between the numbers 5 and 6 and 20, have paired kinetosomes.
The silver line system runs lengthways, with a secondary meridian always running between every two main meridians. The mucocysts are arranged in individual rows between two kinets; during their regeneration, the secondary meridians of the silver line system divide into two parallel lines with isolated anastomoses .
The macronucleus is approximately round and measures between 12 and 20 micrometers in diameter, the contractile vacuole between 6 and 12 micrometers. The latter is located in the front third of the cell, its excretion pore measures around 1 micrometer and lies between kinets 5 and 7.
The cilia are 8 to 10 micrometers long, those at the rear end 12 to 15 micrometers. Dexiostomas move very quickly, always rotating around their own longitudinal axis.
Way of life
The species, which is widespread worldwide, is found in ponds, lakes and rivers, where it mainly lives polysaprobic and eats bacteria . But it can also absorb detritus . The salt tolerance is low, but that of ammonium is very high.
Systematics
From the closely related genus Colpidium , to which it was long counted, the species was separated in 1967 on the basis of the position and shape of the proral suture as well as its deviating oral infraciliature and was first described by AW Jankowski as a monotypical genus. The separation is controversial to the present day, but is supported by molecular genetic studies. In addition to the genus Colpidium , the genera Paracolpidium and Tetrahymena are closely related .
proof
- Wilhelm Foissner , Hubert Schiffmann: Taxonomy and phylogeny of the genus Colpidium (Ciliophora, Tetrahymenidae) and new description of Colpidium truncatum STOKES, 1885. In: Naturkundliches Jahrbuch der Stadt Linz. Volume 24, 1978, pp. 21-40 ( PDF on ZOBODAT ).
- Bruno Ganner, Wilhelm Foissner: Taxonomy and ecology of some ciliates (Protozoa, Ciliophora) of the saprobic system. III. Revision of the genera Colpidium and Dexiostoma, and establishment of a new genus, Paracolpidium nov. gen. Hydrobiologia, 182: 3, 1989, pp. 181-218.
Individual evidence
- ↑ Thomas Posch, Hartmut Arndt: Uptake of sub-micrometre- and micrometre-sized detrital particles by bacterivorous and omnivorous ciliates. In: Aquatic Microbial Ecology, Vol. 10, 1996, pp. 45-53.
- ↑ David L. Nanney, Chaeryung Park, Rosamaria Preparata, Ellen M. Simon: Comparison of Sequence Differences in a Variable 23S rRNA Domain among Sets of Cryptic Species of Ciliated Protozoa in: Journal of Eukaryotic Microbiology, 45: 1, 1998, pp. 91-100.