Arachnidiopsis paradoxa
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| Scientific name | ||||||||||||
| Arachnidiopsis paradoxa | ||||||||||||
| Penard , 1918 |
Arachnidiopsis paradoxa is an eyelash animal of uncertain systematic position. After its discovery in 1918, it has been considered lost since 1937. It was not until 2006 that it was rediscovered.
description
The descriptions of Penard and Kreutz give way to z. T. clearly from each other. This may be due to the small number of specimens that Kreutz found in 2006.
| feature | Penard | cross |
|---|---|---|
| length | 30-48 µm | 25-30 µm |
| shape | round to elongated oval, partly pointed at the end | oval, partly pointed at the end |
| Attachments | two tentacles at the anterior end, no cilia | like Penard |
The representations of Penard and Kreutz differ primarily with regard to the tentacles.
| feature | Penard | cross |
|---|---|---|
| length | highly changeable (can be withdrawn) | about 30 µm |
| thickness | highly variable (can be flattened) | 2.2-4.5 µm |
| cross-section | flat to tubular | oval |
| Interior construction | filled with water | homogeneous hyaline |
In addition, according to Penard, the tentacles should be long enough to twist along the longitudinal axis and attach themselves to objects. However, both could not be confirmed by Kreutz.
Move
The tentacles are in constant oar-like motion, often twisting in a spiral.
Arachnidiopsis paradoxa is also able to move amoeboidly , although the purpose of this movement is unclear.
Habitat and manner
Judging by the findings so far, Arachnidiopsis paradoxa lives mainly in and from detritus . However, Penard and Kreutz were also able to detect symbiotic bacteria inside cells.
Taxonomic position
Because of the round nucleus, Penard suspected that it could be infusoria. Alfred Kahl classified them in 1935 as ciliates of an unclear position. However, to date it has not been possible to detect the so-called nuclear dimorphism , the typical combination of two cell nuclei of different sizes (micro and macronucleus) for ciliates. Only one macronucleus could be detected so far.
The amoeboid movement and the symbiotic bacteria could also indicate a relationship to the amoeba.
Find history
Arachnidiopsis paradoxa was discovered by Eugène Penard in two places in the Geneva area . The first was a swamp known as the "Swamp of Pinchat". The exact location is unclear today. However, it is considered likely that it was the present-day Geneva district of Pinchat . The second site was most likely a pond in the center of Geneva in the Parc de l'Ariana , but this pond was filled in when the Palais des Nations was built.
In 1937 Penard then published an article in which he called for the search for Arachnidiopsis paradoxa . Since then, the organism has been considered lost.
The re-discovery was made in 2006, Martin Kreutz in the sludge of Simmel Ried in Konstanz . After 15 years of intensive research, one specimen each was discovered in July and November of that year. Since one burst prematurely and the other, discovered more by chance, was too contaminated with detritus , only a limited investigation could be carried out.
literature
- Martin Kreutz: Encounter with Arachnidiopis paradoxa . In: microcosm. Volume 97, Issue 1, 2008. ISSN 0026-3680 .
- Martin Kreutz, W. Foissner: The Sphagnum ponds of Simmelried in Germany: A bio-diversity hot-spot for microscopic organisms . In: Protozoological Monographs. Vol. 3, 2006. Shaker Verlag , Aachen.
- Alfred Kahl: primeval animals or protozoa (Infusoria) . In: F. Dahl (Ed.): Die Tierwelt Deutschlands . Gustav Fischer Verlag, Jena 1935.
- Eugène Penard: L ' Arachnidopsis paradoxa. In: Bull. Soc. Franc. Micr. Paris 6, 20-21 (1937).