Austropotamobius bihariensis


Austropotamobius bihariensis is a species of crayfish in the family Astacidae. It is known to exist only in Romania, being restricted to the rivers in the western Apuseni Mountains. Its proposed English common name 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 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 '','' it has a shorter rostrum, the antennal scale is smooth without denticules, and the claws are covered with tubercules that are bigger and fewer than on the stone crayfish claws.

Ecology

European crayfish species prefer 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 and the upper area of the Arieș river. The holotype was collected from Damiș River, Bratca commune, Bihor county.

Conservation

A. bihariensis populations were previously treated as A. torrentium. The total population was estimated at 31,150 individuals, with 1,163,754 m² of suitable habitat, but only 37.9% of this habitat lies within protected areas.
In Romania, A. bihariensis is protected in national legislation. According to the Emergency Ordinance no. 57/2007, which implements the EU Habitats Directive, the species is listed in Annex 3 and Annex 5, requiring the designation of Sites of Community Importance and Special Areas of Conservation to ensure its protection.