''Austropotamobius bihariensis'' is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

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 ...

in the family Astacidae. It is known to exist only in

Romania Romania ( ; ro, România ) is a country located at the crossroads of Central Europe, Central, Eastern Europe, Eastern, and Southeast Europe, Southeastern Europe. It borders Bulgaria to the south, Ukraine to the north, Hungary to the west, S ...

being restricted to the rivers in the western Apuseni Mountains. Its proposed English

common name In biology, a common name of a taxon or organism (also known as a vernacular name, English name, colloquial name, country name, popular name, or farmer's name) is a name that is based on the normal language of everyday life; and is often contrast ...

is idle crayfish. It is supposed to have diverged/split ~15 Ma old from a common relative of ''A. torrentium'' from the Dinarides and evolved isolated due to the historically tectonic north-eastern movement of Tisza-Dacia mega-unit (including the Apuseni Mountains) through the Pannonian Basin, during the Miocene. The molecular divergence in 582 base length nucleotides of COI mtDNA sequences is supported by 43 mutational steps, a differentiation of 7.4% from the sister clade of ''A. torrentium'' located in north-western Dinarides

Description

This crayfish strongly resembles its close relative '' A. torrentium''. The individuals, not longer than 10 cm, are brown dorsally, showing lighter colors on the ventral side with hints of orange on the claws. In comparison with ''

Austropotamobius torrentium ''Austropotamobius torrentium'', also called the stone crayfish, is a European species of fresh water, freshwater crayfish in the family Astacidae. It is mostly found in tributaries of the Danube, having originated in the northern part of the Bal ...

'' (the stone crayfish)'','' it has a shorter rostrum, the

antennal Antennae ( antenna), sometimes referred to as "feelers", are paired appendages used for sensing in arthropods. Antennae are connected to the first one or two segments of the arthropod head. They vary widely in form but are always made of one o ...

scale is smooth without denticules and the claws are covered with tubercules that are bigger and not as many as on the stone crayfish claws. File:Scale A bihariensis 01.jpg, Antennal scale of ''Austropotamobius bihariensis'' File:Scale A torrentium.jpg, Antennal scale of ''Austropotamobius torrentium''

Ecology

European crayfish species prefer in general clean waters, but their tolerance to water pollution is variable. ''A. bihariensis'' seems to prefer cleaner and better oxygenated rivers than the stone crayfish.

Distribution

All the populations of ''A. bihariensis'' are found in the upper sectors of Criș rivers (

Crișul Alb The Crișul Alb (Romanian), ( Hungarian: Fehér-Körös) is a river in western Romania, in the historical region of Transylvania, and in south-eastern Hungary (Békés County). Its source is in the southern Apuseni Mountains (Romanian: Munții A ...

Crișul Negru The Crișul Negru (Black Criș) (Romanian), ( hu, Fekete-Körös) is a river in western Romania (Transylvania) and south-eastern Hungary (Békés County). The river has its source in the western Apuseni Mountains. It flows through the towns Ștei ...

and Crișul Repede). The

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several ...

(deposited at the

Grigore Antipa National Museum of Natural History The Grigore Antipa National Museum of Natural History ( ro, Muzeul Național de Istorie Naturală „Grigore Antipa”) is a natural history museum, located in Bucharest, Romania. It was originally established as the National Museum of Natural H ...

) was collected from Damiș river, Bratca commune, Bihor county.

Conservation

''A. bihariensis'' populations were previously treated as ''A. torrentium'' (a threatened species, listed in the

IUCN Red List The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is the world's most comprehensive inventory of the global conservation status of biol ...

and in the appendix of the Bern Convention and EU Habitats Directive. Conservation status of the idle crayfish is not assessed. Along with other crayfish species from Europe, the idle crayfish faces several threats, among which, the pressure of invasive species is very important

References

{{Taxonbar, from=Q65068622 Astacidae Fauna of Romania Endemic fauna of Romania