Italian jackdaw crab

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Italian jackdaw crab
Austropotamobius italicus Jackdaw Shrimp.JPG

Italian jackdaw crab ( Austropotamobius italicus )

Systematics
Subordination : Pleocyemata
Partial order : Large crayfish (Astacidea)
Superfamily : Crayfish (Astacoidea)
Family : Astacidae
Genre : Austropotamobius
Type : Italian jackdaw crab
Scientific name
Austropotamobius italicus
Faxon , 1914

The Italian jackdaw crab ( Austropotamobius italicus ) is a European species of crayfish. Its home is Italy and the western Balkan Peninsula, other occurrences, for example in Spain, may be traced back to animals abandoned by humans, but others assume an autochthonous occurrence here. Its taxonomic status is also controversial; many authors consider it a subspecies or form of the jackdaw crab ( Austropotamobius pallipes ). Today it is threatened in its entire area by pollution and degradation of the waters, but even more by the effects of North American crayfish that have been released and naturalized by humans.

features

The differentiation of the Italian jackdaw crab from the jackdaw crab based on morphological characteristics is uncertain; the characteristics used are assessed differently by different authors and may not apply equally to all populations. To differentiate according to genetic characteristics, see below (section Taxonomy ). Both types of jackdaw crayfish differ most easily from the closely related stone crayfish ( Austropotamobius torrentium ) in that they form a group on the side of the carapace behind the cervical furrow (this is the conspicuous semicircular seam that divides the carapace into front and rear halves when viewed from above) bear conspicuous thorns. Jackdaw crabs and Italian jackdaw crabs are differentiated according to the following characteristics: The rostrum (the pointed protrusion of the carapace between the eyes) is more trapezoidal in A. italicus , with well-developed lateral spines, in A. pallipes i. e. S. rather triangular without rostral thorns or only with wart-like protrusions in their place. The surface of the cephalothorax in A. italicus is rougher, not as smooth as in A. pallipes , and the surface of the scissors is more coarsely granulated. In the male, the first pair of gonopods , the extremities of the pleon transformed into mating organs, often have an asymmetrical tip, in A. pallipes it is always symmetrical. More noticeable features such as size, color, shape of the scissors or the length of the rostrum are extremely variable and not suitable for differentiation.

distribution

The Italian jackdaw crab is only found south of the Alps. He lives all over Italy to the south, in Carinthia (Austria) as well as in Slovenia, Croatia and Bosnia. In north-western Italy, in Piedmont, there is an area in which Italian jackdaw crabs and jackdaw crabs presumably occur side by side ( sympatric ), partly in the same water system (in the rivers Lemme, Borbera and Scrivia ), this is also the case for part of the French Maritime Alps (Orobische Alps). The assignment of some populations living in the Apennines is difficult, however. Evidence of the Balkans exists almost only in waters that drain from the Dinaric Mountains to the Adriatic Sea, in Slovenia and Croatia, and the Istrian peninsula ., Possibly also in Bosnia There are also rare occurrences in tributaries draining towards the Danube. The Spanish occurrences also belong to this species.

Due to the genetic uniformity of the Spanish populations (with marginal occurrences also in Portugal) it was assumed that these go back to abandoned animals, probably imported from Italy as early as the Middle Ages. Other studies found larger genetic differences, which make it possible to differentiate the populations from the pre-ice age. The status of the Spanish populations is therefore still unclear.

Ecology and way of life

The Italian jackdaw crab lives in clean, oxygen-rich waters that contain at least 2.8 milligrams of dissolved calcium per liter, so it is absent in areas with acidic rocks and very soft water. It prefers flowing waters with stony or sandy-stony bottoms and lakes, especially in the mountains. The species tolerates little water pollution.

Taxonomy

The shape of the jackdaw crab ( Austropotamobius pallipes in the broader sense) is difficult and has not yet been clearly clarified. While some reviewers traditionally only recognize one species, with different varieties, others were independent species and subspecies e.g. B. from Carinthia, Ticino, Spain and Croatia. By comparing the base sequence of the MtDNA , Grandjean et al. 2000 divided into two clades , for which they used the species names A. pallipes and A. italicus . All later concepts of the Italian jackdaw crab build on its use in this work. The morphological features suggested by the earlier investigators for differentiation proved to be too variable for addressing in detail, but correlate in part with the genetically differentiated populations.

Other genetic studies, using other sequence sections, have confirmed the differentiation in the nucleus, but in some cases produced a more complicated and contradicting picture. While most researchers therefore recognize the Italian jackdaw crab as a separate species, others consider it only as a subspecies (or population group) within a broad species A. pallipes .

Fratini et al. think it is possible to divide the Italian jackdaw crab into four subspecies using genetic markers. These would be A. italicus italicus , A. italicus carinthiacus , A. italicus carsicus , A. italicus meridionalis . In some cases, forms or subspecies established earlier on a morphological basis. According to other studies, however, this classification is subject to considerable reservations, so it is currently unclear whether it can be confirmed.

Hazard and protection

The collective species Austropotamobius pallipes including A. italicus is considered endangered according to the IUCN Red List . Although the species has lost many occurrences, especially at lower altitudes, due to water pollution or morphological water development, the main source of threat is displacement by exotic crayfish species introduced from North America. Since many of these species are more heat-loving, they still have local refuges in the upper reaches of rivers. But as soon as an American species is established in a body of water, the Italian jackdaw shrimp disappears there. In addition to direct competition, this is primarily due to the cancer plague transmitted by American species . It is therefore believed that it has lost more than half of its previous occurrences in the past few decades.

The collection type is listed in Appendix II and Appendix V of the Fauna-Flora-Habitat Directive of the EU and in Appendix III of the Bern Convention . The member states of the European Union are obliged to take protective measures for the species, in particular to designate special protected areas for their conservation. Economic use can also be restricted. Although the species used to be important for fishing, its use no longer plays an economic role today, although illegal use (e.g. in Italy) still occurs.

Individual evidence

  1. ^ A b F. Grandjean, N. Gouin, M. Frelon, C. Souty-Grosset (1998): Genetic and Morphological Systematic Studies on the Crayfish Austropotamobius pallipes (Decapoda: Astacidae). Journal of Crustacean Biology Vol. 18, No. 3: 549-555
  2. ↑ cf. z. B. Manfred Pöckl (1992): Identification key for Austrian crayfish (class Crustacea, subclass Malacostraca, order Decapoda, department Astacura). Lauterbornia 10: 1-8.
  3. ↑ Mladen S. Karaman (1962): A contribution to the systematics of the Astacidae (Decapoda). Crustaceana Vol. 3, No. 3: 173-191.
  4. ^ Richard Bott (1950): The river crabs of Europe (Decapoda, Astacidae). Treatises of the Senckenberg Natural Research Society, Volume 483
  5. ↑ S. Zaccara, F. Stefani, P. Galli, PA Nardi, G. Crosa (2004): Taxonomic implications in conservation management of white-clawed crayfish (Austropotamobius pallipes) (Decapoda, Astacidae) in Northern Italy. Biological Conservation 120: 1-10. doi : 10.1016 / j.biocon.2004.01.020
  6. ↑ a b Peter Trontelj, Yoichi Machino, Boris Sket (2005): Phylogenetic and phylogeographic relationships in the crayfish genus Austropotamobius inferred from mitochondrial COI gene sequences. Molecular Phylogenetics and Evolution 34: 212-226.
  7. ^ DM Holdich (2002): Distribution of crayfish in Europe and some adjoining countries. Bulletin Francais de la Pêche et de la pisciculture 367: 611-650.
  8. ^ F. Grandjean, N. Gouin, C. Souty-Groset, J. Diéguez-Uribeondo (2000): Drastic bottlenecks in the endangered crayfish species Austropotamobius pallipes in Spain and implications for its colonization history. Heredity 86: 1-8.
  9. ↑ Carlos Pedraza-Lara, Fernando Alda, Salvador Carranza, Ignacio Doadrio (2010): Mitochondrial DNA structure of the Iberian populations of the white-clawed crayfish, Austropotamobius italicus italicus (Faxon, 1914). Molecular Phylogenetics and Evolution 57: 327-342. doi : 10.1016 / j.ympev.2010.06.007
  10. ^ M Scalici, G Gibertini (2005): Can Austropotamobius italicus meridionalis be used as a monitoring instrument in Central Italy? Preliminary observations. Bulletin Francais de la Pêche et de la pisciculture 376-377: 613-625. doi : 10.1051 / kmae: 2005019
  11. ^ Henning Albrecht (1982): The system of European river crabs. (Decapoda, Astacidae): proposal and justification. Messages from the Hamburg Zoological Museum and Institute Volume 79: 187-210.
  12. ↑ Frédéric Grandjean, D. James Harris, Catherine Souty-Grosset, Keith A. Crandall (2000): Systematics of the European endangered crayfish species Austropotamobius pallipes (Decapoda: Astacidae). Journal of Crustacean Biology Vol. 20, Issue 3: 522-529 doi : 10.1651 / 0278-0372 (2000) 020 [0522: SOTEEC] 2.0.CO; 2
  13. ↑ S. Fratini, S. Zaccara, S. Barbaresi, F. Grandjean, C. Souty-Grosset, G. Crosa, F. Gherardi (2005): Phylogeography of the threatened crayfish (genus Austropotamobius) in Italy: implications for its taxonomy and conservation. Heredity 94: 108-118. doi : 10.1038 / sj.hdy.6800581
  14. ↑ The IUCN Red List of Threatened Species: Austropotamobius pallipes
  15. ↑ Jose M. Gil-Sanchez, Javier Alba-Tercedor (2002): Ecology of the native and introduced crayfishes Austropotamobius pallipes and Procambarus clarkii in southern Spain and implications for conservation of the native species. Biological Conservation 105: 75-80.