Jackdaw crab
| Jackdaw crab | ||||||||||||
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Jackdaw Shrimp ( Austropotamobius (p.) Pallipes ) |
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| Austropotamobius pallipes | ||||||||||||
| ( Lereboullet , 1858) |
The jackdaw crayfish ( Austropotamobius pallipes ) is a species of crayfish (Astacidae) native to southern, western and central Europe . In Germany it is the rarest native river crayfish, as it only occurs in the southwest of Baden-Württemberg, where it reaches its northeastern limit of distribution. The jackdaw crayfish is the sister species of the stone crayfish and differs from it by clear thorns behind the neck furrow. It is endangered by habitat loss and water pollution as well as by invasive, non-native crayfish and crayfish plague throughout its range. In Germany, the jackdaw crab is threatened with extinction (Red List Category 1).
Scientific name: gr. Potamos = river, bios = life; Latin oyster = south, pallidus = pale (?) and pes = foot
description
The color is brownish. The claws of the jackdaw shrimp are broad and strong. The top is usually a dark chocolate brown, the underside of the scissors is more whitish. Behind the neck furrow there are two to three clearly visible thorns and only a pair of eye ridges. The back furrows run separately from the neck furrow to the rear edge of the breastplate. The sides in front of the neck furrow are smooth. It becomes up to 10 cm long. It has flattened end links that form a tail fan.
Gender recognition
Females stay significantly smaller than males. The males (like all astacids) not only have sexual openings between the fifth pair of legs, but also mating pens (gonopods). In females you can see genital openings (gonopores) on the third pair of legs. The abdomen (tail segment) in females is also significantly wider than in males.
Systematics
The jackdaw crab is a complex of species that may include several species and subspecies. More recent molecular genetic and morphological studies confirm a split into two forms with uncertain species status: Austropotamobius (p.) Pallipes and A. (p.) Italicus . Austropotamobius (p.) Pallipes includes the form originally described by Lereboullet (nominate form) and is mainly found in France, England, southern Baden and north-western Switzerland. Austropotamobius (p.) Italicus is a southern European form that occurs in Italy, southern France, southern Switzerland, Istria and along the Dalmatian coast. The jackdaw crab stocks on the Iberian Peninsula also belong to A. (p.) Italicus , but possibly go back to a historical displacement, probably from northern Italy. In western Austria there is also an allochthonous population of A. (p.) Italicus , which locally displaces the indigenous stone crayfish.
habitat
The jackdaw crab has a very wide temperature tolerance. It occurs in waters that have summer temperatures of 10 ° C to 24 ° C. Its habitat ranges from small streams to swampy, boggy still waters. He's not very picky about his cave dwelling either. It is sensitive to chemical and organic pollution, especially insecticides. The jackdaw crabs live in caves and tree roots in the bank area in slowly flowing but deep waters.
distribution
The jackdaw crab has always occurred in Germany only in a narrowly limited area of the southern Upper Rhine, the High Rhine and in the foothills of the Black Forest, where the north-eastern limit of its distribution area lies in Germany. As a rule, it no longer occurs east of the Rhine. It is the most common type of cancer in England and France. The German deposits were unknown for years and were only rediscovered and described in the late 1980s. In older literature, however, there are already concrete references to its distribution in the western Upper Rhine plain in Alsace. In Switzerland it can be found in the Crestasee and probably also in the Caumasee .
Web links
- Online identification key for crayfish in Baden-Württemberg
- Crayfish in Austria (PDF file, 2.5 MB)
- Austropotamobius pallipes in the endangered Red List species the IUCN 2006 Posted by: B. Sket, 1996. Retrieved on 10 May, 2006.
Individual evidence
- ↑ C. Chucholl, P. Dehus, (2011): Crayfish in Baden-Württemberg . Fisheries Research Center Baden-Württemberg (FFS), Langenargen, 92 pages
- ↑ Chucholl, C. & Blank, S. & Brinker, A. (2017): The protection of the crayfish - A guide . Ministry for Rural Areas and Consumer Protection Baden-Württemberg, Stuttgart, 84 pages