The Parastacidae are the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

freshwater Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. The term excludes seawater and brackish water, but it does include non-salty mi ...

crayfish Crayfish are freshwater crustaceans belonging to the infraorder Astacidea, which also contains lobsters. Taxonomically, they are members of the superfamilies Astacoidea and Parastacoidea. They breathe through feather-like gills. Some spe ...

found in the Southern Hemisphere. The family is a classic

Gondwana Gondwana ( ; ) was a large landmass, sometimes referred to as a supercontinent. The remnants of Gondwana make up around two-thirds of today's continental area, including South America, Africa, Antarctica, Australia (continent), Australia, Zea ...

-distributed taxon, with

extant Extant or Least-concern species, least concern 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 * Exta ...

members in

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

Madagascar Madagascar, officially the Republic of Madagascar, is an island country that includes the island of Madagascar and numerous smaller peripheral islands. Lying off the southeastern coast of Africa, it is the world's List of islands by area, f ...

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

New Zealand New Zealand () is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and List of islands of New Zealand, over 600 smaller islands. It is the List of isla ...

, and

New Guinea New Guinea (; Hiri Motu: ''Niu Gini''; , fossilized , also known as Papua or historically ) is the List of islands by area, world's second-largest island, with an area of . Located in Melanesia in the southwestern Pacific Ocean, the island is ...

, and

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

taxa In biology, a taxon (back-formation from ''taxonomy''; : taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular name and ...

also in

Antarctica Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean (also known as the Antarctic Ocean), it contains the geographic South Pole. ...

Classification and phylogeny

Parastacidae belongs to the superfamily Parastacoidea, the

monotypic taxon In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of Genus, genera, the term ...

which contains all

in the Southern Hemisphere. Parastacoidea is the

sister taxon In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and ...

to Astacoidea, which contains all crayfish of the

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 by humans as being in the same celestial sphere, celestial hemisphere relative to the invariable plane of the Solar ...

. Crayfish and

lobster Lobsters are Malacostraca, malacostracans Decapoda, decapod crustaceans of the family (biology), family Nephropidae or its Synonym (taxonomy), synonym Homaridae. They have long bodies with muscular tails and live in crevices or burrows on th ...

s together comprise the

infraorder Order () is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between Family_(biology), family and Class_(biology), class. In biological classification, the order is a taxonomic rank used in the classific ...

Astacidea Astacidea is an infraorder of decapod crustaceans including lobsters (but not "lobsters" such as the spiny lobster etc.), crayfish, and their close relatives. Description The Astacidea are distinguished from most other decapods by the presence ...

, as shown in the simplified

cladogram A cladogram (from Greek language, Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an Phylogenetic tree, evolutionary tree because it does not s ...

below:

Distribution

Three genera are found in

Chile Chile, officially the Republic of Chile, is a country in western South America. It is the southernmost country in the world and the closest to Antarctica, stretching along a narrow strip of land between the Andes, Andes Mountains and the Paci ...

, '' Virilastacus'', '' Samastacus'' and '' Parastacus'', the last of which also occurs disjunctly in

southern Brazil The South Region of Brazil ( ) is one of the five regions of Brazil. It includes the states of Paraná, Rio Grande do Sul, and Santa Catarina, and covers , being the smallest region of the country, occupying only about 6.76% of the territory of ...

and

Uruguay Uruguay, officially the Oriental Republic of Uruguay, is a country in South America. It shares borders with Argentina to its west and southwest and Brazil to its north and northeast, while bordering the Río de la Plata to the south and the A ...

. There are no crayfish native to continental Africa, but seven species on

, all of the genus '' Astacoides''.

Australasia Australasia is a subregion of Oceania, comprising Australia, New Zealand (overlapping with Polynesia), and sometimes including New Guinea and surrounding islands (overlapping with Melanesia). The term is used in a number of different context ...

is particularly rich in crayfish. The small genus ''

Paranephrops ''Paranephrops'' is a genus of freshwater crayfish found only in New Zealand. They are known by the English common names freshwater crayfish and koura, the latter from their Māori language, Māori name of ''kōura''. Species The two species a ...

'' is

endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

. The genera '' Astacopsis'' is endemic to

Tasmania Tasmania (; palawa kani: ''Lutruwita'') is an island States and territories of Australia, state of Australia. It is located to the south of the Mainland Australia, Australian mainland, and is separated from it by the Bass Strait. The sta ...

, while a further two are found on either side of the

Bass Strait Bass Strait () is a strait separating the island state of Tasmania from the Mainland Australia, Australian mainland (more specifically the coast of Victoria (Australia), Victoria, with the exception of the land border across Boundary Islet). The ...

– '' Geocharax'' and '' Engaeus''. The greatest diversity, however, is found on the Australian mainland. Three genera are endemic and have restricted distributions ('' Engaewa'', '' Gramastacus'' and '' Tenuibranchiurus''), while two are more widespread and contain more than one hundred species between them: '' Euastacus'', around the Australian coast from

Melbourne Melbourne ( , ; Boonwurrung language, Boonwurrung/ or ) is the List of Australian capital cities, capital and List of cities in Australia by population, most populous city of the States and territories of Australia, Australian state of Victori ...

Brisbane Brisbane ( ; ) is the List of Australian capital cities, capital and largest city of the States and territories of Australia, state of Queensland and the list of cities in Australia by population, third-most populous city in Australia, with a ...

, and ''

Cherax ''Cherax'', commonly known as yabby/yabbies in Australia, is the most widespread genus of fully aquatic crayfish in the Southern Hemisphere. Various species of cherax may be found in both still and flowing bodies of freshwater across most of A ...

'' across Australia and

. The Tasmanian genus ''Parastacoides'' was determined to be a synonym of ''Geocharax'', and is no longer valid.

Fossil record

The oldest specimens from the family Parastacidae are the

Albian The Albian is both an age (geology), age of the geologic timescale and a stage (stratigraphy), stage in the stratigraphic column. It is the youngest or uppermost subdivision of the Early Cretaceous, Early/Lower Cretaceous epoch (geology), Epoch/s ...

fossils of '' Palaeoechinastacus'' from

Victoria, Australia Victoria, commonly abbreviated as Vic, is a state in southeastern Australia. It is the second-smallest state (after Tasmania), with a land area of ; the second-most-populated state (after New South Wales), with a population of over 7 million; ...

. The only northern hemisphere representative is also a fossil, '' Aenigmastacus crandalli'' from

Canada Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...

References

External links

* {{Authority control Crayfish Extant Albian first appearances Taxa named by Thomas Henry Huxley Decapod families