''Astacus'' (from the Greek , ', meaning "lobster" or "crayfish") is a genus of

crayfish Crayfish are freshwater crustaceans belonging to the clade Astacidea, which also contains lobsters. In some locations, they are also known as crawfish, craydids, crawdaddies, crawdads, freshwater lobsters, mountain lobsters, rock lobsters, mu ...

found in Europe and western Asia, comprising three

extant Extant is the opposite of the word extinct. It may refer to: * Extant hereditary titles * Extant literature, surviving literature, such as ''Beowulf'', the oldest extant manuscript written in English * Extant taxon, a taxon which is not extinct, ...

(living) species and three

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

fossil species. Due to the crayfish plague, crayfish of this genus have declined in many European regions, being replaced by the

invasive Invasive may refer to: *Invasive (medical) procedure *Invasive species *Invasive observation, especially in reference to surveillance *Invasively progressive spread of disease from one organ in the body to another, especially in reference to cancer ...

North American signal crayfish, which carries the plague but is unaffected by it.

Classification

''Astacus'' belongs to the family Astacidae, one of the three families of

Northern Hemisphere The Northern Hemisphere is the half of Earth that is north of the Equator. For other planets in the Solar System, north is defined as being in the same celestial hemisphere relative to the invariable plane of the solar system as Earth's Nort ...

freshwater crayfish within the

superfamily SUPERFAMILY is a database and search platform of structural and functional annotation for all proteins and genomes. It classifies amino acid sequences into known structural domains, especially into SCOP superfamilies. Domains are functional, str ...

Astacoidea. The internal phylogeny of Astacidae can be shown in the cladogram below:

Extant species

*'' Astacus astacus'' (Linnaeus, 1775) - known as the "European crayfish", "noble crayfish" or "broad-fingered crayfish" - it is distributed across Europe, in France throughout Central Europe, to the

Balkan Peninsula The Balkans ( ), also known as the Balkan Peninsula, is a geographical area in southeastern Europe with various geographical and historical definitions. The region takes its name from the Balkan Mountains that stretch throughout the who ...

, and north as far as parts of the British Isles, Scandinavia, and the western parts of the former Soviet Union. It is the most common species of

in Europe, and a traditional foodstuff. Like other crayfish, ''A. astacus'' is restricted to

fresh water Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the term specifically excludes seawater and brackish water, it does include ...

, living only in unpolluted streams, rivers, and lakes. Males may grow up to 16 cm long, and females up to 12 cm. *'' Astacus balcanicus'' (Karaman, 1929) - found in the Vardar river basin, Lake Pamvotida ( Greece) and Lake Ohrid ( North Macedonia/eastern Albania) *'' Astacus colchicus'' Kessler, 1876 - can be found in Rioni river basin ( Georgia)

Fossil species

*?'' Astacus edwardsii'' Van Straelen, 1928 - France - proposed to new genus '' Emplastron'' in 2021 study *'' Astacus laevissimus'' Fritsch & Kafka, 1887 - Czech Republic *'' Astacus multicavatus'' Bell, 1863 - United Kingdom

References

{{Taxonbar, from=Q1942450 Astacidae Crustacean genera Taxa named by Johan Christian Fabricius