''Faxonius immunis'' 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

Cambaridae The Cambaridae are the largest of the four families of freshwater crayfish, with over 400 Species. Most of the species in the family are native the United States east of the Great Divide and Mexico, but fewer range north to Canada, and south to ...

. It is native to North America and it is an

introduced species An introduced species, alien species, exotic species, adventive species, immigrant species, foreign species, non-indigenous species, or non-native species is a species living outside its native distributional range, but which has arrived there ...

in Europe, where it lives along the

Upper Rhine The Upper Rhine (german: Oberrhein ; french: Rhin Supérieur) is the section of the Rhine between Basel in Switzerland and Bingen in Germany, surrounded by the Upper Rhine Plain. The river is marked by Rhine-kilometres 170 to 529 (the sc ...

. Its common names include calico crayfish and papershell crayfish.Adams, S., Schuster, G.A. & Taylor, C.A. 2010
''Orconectes immunis''.
The IUCN Red List of Threatened Species 2010. Downloaded on 16 June 2016.

Taxonomy

''Faxonius immunis'' was first described by

Hermann August Hagen Hermann August Hagen (30 May 1817 – 9 November 1893) was a German entomologist who specialised in Neuroptera and Odonata. He had established himself as one of Europe's preeminent entomologists by 1867 when he accepted a position at Harvard Unive ...

in 1870, in his ''Monograph of the North American Astacidae'', under the name ''Cambarus immunis''. The original specimens came from Lawn Ridge, Marshall County,

Illinois Illinois ( ) is a U.S. state, state in the Midwestern United States, Midwestern United States. Its largest metropolitan areas include the Chicago metropolitan area, and the Metro East section, of Greater St. Louis. Other smaller metropolita ...

Description

''Faxonius immunis'' is similar to a number of species of crayfish in the genus ''

Faxonius ''Faxonius'' is a genus of freshwater crayfish in the family Cambaridae. There are more than 90 described species in ''Faxonius''. It includes the rusty crayfish, an invasive species in North America, and three species, ''F. virilis'', ''F. immu ...

''. While the colouration of the claws is distinctive, it can be difficult to use that to identify a specimen without reference specimens for comparison. ''F. immunis'' can be distinguished from '' F. virilis'' by the presence of a notch near the base of the ''dactylus'' (finger) of the claw, which is not found in ''F. virilis''.

Distribution and habitat

North America

''Faxonius immunis'' naturally occurs across a wide area of eastern North America, from

Maine Maine () is a state in the New England and Northeastern regions of the United States. It borders New Hampshire to the west, the Gulf of Maine to the southeast, and the Canadian provinces of New Brunswick and Quebec to the northeast and north ...

and

Connecticut Connecticut () is the southernmost state in the New England region of the Northeastern United States. It is bordered by Rhode Island to the east, Massachusetts to the north, New York to the west, and Long Island Sound to the south. Its cap ...

in the east to

Colorado Colorado (, other variants) is a state in the Mountain West subregion of the Western United States. It encompasses most of the Southern Rocky Mountains, as well as the northeastern portion of the Colorado Plateau and the western edge of t ...

and

Wyoming Wyoming () is a U.S. state, state in the Mountain states, Mountain West subregion of the Western United States. It is bordered by Montana to the north and northwest, South Dakota and Nebraska to the east, Idaho to the west, Utah to the south ...

in the west, and from

Alabama (We dare defend our rights) , anthem = "Alabama (state song), Alabama" , image_map = Alabama in United States.svg , seat = Montgomery, Alabama, Montgomery , LargestCity = Huntsville, Alabama, Huntsville , LargestCounty = Baldwin County, Al ...

in the south and north to

Manitoba Manitoba ( ) is a Provinces and territories of Canada, province of Canada at the Centre of Canada, longitudinal centre of the country. It is Canada's Population of Canada by province and territory, fifth-most populous province, with a population o ...

Ontario Ontario ( ; ) is one of the thirteen provinces and territories of Canada.Ontario is located in the geographic eastern half of Canada, but it has historically and politically been considered to be part of Central Canada. Located in Central Ca ...

and

Quebec Quebec ( ; )According to the Canadian government, ''Québec'' (with the acute accent) is the official name in Canadian French and ''Quebec'' (without the accent) is the province's official name in Canadian English is one of the thirtee ...

in Canada. Populations in Quebec may be the result of introductions by anglers from

New York New York most commonly refers to: * New York City, the most populous city in the United States, located in the state of New York * New York (state), a state in the northeastern United States New York may also refer to: Film and television * '' ...

; the Canadian populations are centered in southern Ontario. It is believed to have been introduced to a number of states in

New England New England is a region comprising six states in the Northeastern United States: Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont. It is bordered by the state of New York to the west and by the Canadian provinces ...

, including

Massachusetts Massachusetts (Massachusett language, Massachusett: ''Muhsachuweesut assachusett writing systems, məhswatʃəwiːsət'' English: , ), officially the Commonwealth of Massachusetts, is the most populous U.S. state, state in the New England ...

New Hampshire New Hampshire is a U.S. state, state in the New England region of the northeastern United States. It is bordered by Massachusetts to the south, Vermont to the west, Maine and the Gulf of Maine to the east, and the Canadian province of Quebec t ...

Rhode Island Rhode Island (, like ''road'') is a U.S. state, state in the New England region of the Northeastern United States. It is the List of U.S. states by area, smallest U.S. state by area and the List of states and territories of the United States ...

and

Vermont Vermont () is a state in the northeast New England region of the United States. Vermont is bordered by the states of Massachusetts to the south, New Hampshire to the east, and New York to the west, and the Canadian province of Quebec to ...

Europe

''Faxonius immunis'' has been popular in the

aquarium An aquarium (plural: ''aquariums'' or ''aquaria'') is a vivarium of any size having at least one transparent side in which aquatic plants or animals are kept and displayed. Fishkeepers use aquaria to keep fish, invertebrates, amphibians, aq ...

trade in Germany, and is kept as a pet both in aquaria and

garden pond A garden pond is a water feature constructed in a garden or designed landscape, normally for aesthetic purposes, to provide wildlife habitat, or for swimming. Habitat Garden ponds can be excellent wildlife habitats, and can make a contribution ...

s. The first recorded escape was a single individual in a small canal in the

Rhine ), Surselva, Graubünden, Switzerland , source1_coordinates= , source1_elevation = , source2 = Rein Posteriur/Hinterrhein , source2_location = Paradies Glacier, Graubünden, Switzerland , source2_coordinates= , so ...

valley of

Baden-Württemberg Baden-Württemberg (; ), commonly shortened to BW or BaWü, is a German state () in Southwest Germany, east of the Rhine, which forms the southern part of Germany's western border with France. With more than 11.07 million inhabitants across a ...

in 1997. Later, a breeding population was discovered, and this has now spread at least as far downstream as

Karlsruhe Karlsruhe ( , , ; South Franconian: ''Kallsruh'') is the third-largest city of the German state (''Land'') of Baden-Württemberg after its capital of Stuttgart and Mannheim, and the 22nd-largest city in the nation, with 308,436 inhabitants. ...

( downstream) and possibly as far as

Speyer Speyer (, older spelling ''Speier'', French: ''Spire,'' historical English: ''Spires''; pfl, Schbaija) is a city in Rhineland-Palatinate in Germany with approximately 50,000 inhabitants. Located on the left bank of the river Rhine, Speyer li ...

( downstream from Karlsruhe). It has since been recorded from other locations in Europe, including the German state of

Rhineland-Palatinate Rhineland-Palatinate ( , ; german: link=no, Rheinland-Pfalz ; lb, Rheinland-Pfalz ; pfl, Rhoilond-Palz) is a western state of Germany. It covers and has about 4.05 million residents. It is the ninth largest and sixth most populous of the ...

, as well as in France. It appears to be out-competing another

invasive species An invasive species otherwise known as an alien is an introduced organism that becomes overpopulated and harms its new environment. Although most introduced species are neutral or beneficial with respect to other species, invasive species ad ...

, '' F. limosus'', which has been present in the area for five decades.

Habitat

''Faxonius immunis'' is only found in slow-flowing bodies of water, such as

stream A stream is a continuous body of water, body of surface water Current (stream), flowing within the stream bed, bed and bank (geography), banks of a channel (geography), channel. Depending on its location or certain characteristics, a stream ...

pond A pond is an area filled with water, either natural or artificial, that is smaller than a lake. Defining them to be less than in area, less than deep, and with less than 30% emergent vegetation helps in distinguishing their ecology from th ...

marsh A marsh is a wetland that is dominated by herbaceous rather than woody plant species.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p Marshes can often be found at ...

es and roadside ditches, in contrast to '' F. virilis'' which also lives in rivers with moderate flow. It can survive in areas with large fluctuations in the amount of available water, by burrowing into the ground when the surface waters recede.

References

{{Taxonbar, from=Q1722252 Cambaridae Freshwater crustaceans of North America Fauna of the Great Lakes region (North America) Fauna of the Eastern United States Crustaceans described in 1870 Taxa named by Hermann August Hagen