''Craterocephalus eyresii'', the Lake Eyre hardyhead, is a species of freshwater

silverside Silverside may refer to: * Silverside (beef), a cut of beef * Silverside (fish), the Atheriniformes, an order of fish * Agnes Silverside (died 1557), one of the Colchester Martyrs * USS ''Silversides'', the name of 2 U.S. Navy submarines * Silver ...

from the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Atherinidae which is

endemic Endemism is the state of a species being found 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 found elsew ...

to the

Lake Eyre Lake Eyre ( ), officially known as Kati Thanda–Lake Eyre, is an endorheic lake in east-central Far North South Australia, some north of Adelaide. The shallow lake is the depocentre of the vast endorheic Lake Eyre basin, and contains the ...

basin in Australia.

Description

''Craterocephalus eyresii'' is a small drab yellowish-grey coloured fish with greenish-silvery underside, and a silver mid-lateral stripe which has some dark melanophores around it., and transparent to yellowish fins. There are two

dorsal fin A dorsal fin is a fin located on the back of most marine and freshwater vertebrates within various taxa of the animal kingdom. Many species of animals possessing dorsal fins are not particularly closely related to each other, though through conv ...

s which are widely separated with the first dorsal fin originating before the tips of the ventral fins and the

anal fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as se ...

origin lies directly underneath the origin of second dorsal fin. The caudal fin is forked. The fins are yellowish in colour. It attains a maximum

total length Fish measurement is the measuring of individual fish and various parts of their anatomies. These data are used in many areas of ichthyology, including taxonomy and fisheries biology. Overall length * Standard length (SL) is the length of a fish ...

of .

Distribution

''Craterocephalus eyresii'' is endemic to Lake Eyre and rivers to the south and west of it in

South Australia South Australia (commonly abbreviated as SA) is a state in the southern central part of Australia. It covers some of the most arid parts of the country. With a total land area of , it is the fourth-largest of Australia's states and territories ...

. It also occurs in

Lake Frome Lake Frome / Munda is a large endorheic lake in the Australian state of South Australia to the east of the Northern Flinders Ranges. It is a large, shallow, unvegetated salt pan, long and wide, lying mostly below sea level and having a total s ...

and its drainage basin in the northern Flinders Ranges as well as Lake Torrens and its tributaries.

Habitat and biology

''Craterocephalus eyresii'' is found in a variety of wetlands from swamps to rivers. It is common wherever it occurs and it is normally found among aquatic vegetation and over gravel substrates in lakes or in the slow-flowing parts of streams. It may be found in both turbid and clear water. It can also inhabit ephemeral rivers, streams, natural springs, salt lakes and man-made bores where it prefers to stay around submerged vegetation over gravel substrates. In dry periods it seeks refuge in bores and semi-permanent waterholes. It mainly feeds on small crustaceans. In permanent waters it breeds from January to March, but will breed opportunistically in flood periods. It is an important component of the diet of many waterbirds such as herons, cormorants and pelicans.

Taxonomy

''Craterocephalus eyresii'' '' sensu lato'' has been split it into four species, the Darling River hardyhead (''C. amniclus''), Finke River hardyhead (''C. centralis''), Lake Eyre hardyhead (''C. eyresii''), and

Murray hardyhead The Murray hardyhead (''Craterocephalus fluviatilis'') is a species of fish in the family Atherinidae endemic to inland parts of southeastern Australia. The fish is an omnivore, feeding on small crustaceans, aquatic insects and algae Algae ...

(''C. fluviatilis''). As the most studied populations have been populations of the Murray hardhead then much of the information which appears to refer to the Lake EYre hardyhead actually refers to the Murray hardyhead.

References

{{Taxonbar, from=Q2223733 eyresii Taxa named by Franz Steindachner Fish described in 1883