Darling River hardyhead

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Darling River hardyhead
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Atheriniformes
Family: Atherinidae
Genus: Craterocephalus
Species:
C. amniculus
Binomial name
Craterocephalus amniculus

The Darling River hardyhead (Craterocephalus amniculus) is a species of fish in the family Atherinidae endemic to Australia. The species name amniculus is from the Latin meaning a small creek or stream, in reference to the habitat where these fish are often found. [2]

Contents

Craterocephalus amniculus is recorded to be vulnerable to becoming an endangered species because of its restricted range, but the threats and information regarding this recording have not been verified or documented. [1]

Description

The Darling River hardyhead is a small, laterally compressed fish that has a slender and elongated body. The large eyes are silvery in colour and it has narrow lips with few teeth in the mouth. The back is a dusky gold colour while it is silvery gold below. There is a dark, silvery stripe that runs the length of the flanks. [3] They attain a maximum length of 55 millimetres (2.2 in). This species has two small, dorsal fin which have short bases and with the second positioned directly over the anal fin. The caudal fin is forked and the pectoral fins are located high on the body while the anal fin has 5–8 rays. It has small scales that infrequently overlap and there is a count of 37–38 along the midlateral with a transverse count of 14–18 scales. Normally there are no scales on top of head, although sometimes small and circular may be present. [4] The mouth is protractile but its gape is restricted by a ligament situated about a third of the way along the mouth. [5]

Distribution

The Darling River hardyhead occurs in the northern section of the Murray-Darling basin where it inhabits the upper tributaries of the River Darling in the border area between Queensland and New South Wales. Within the Murray-Darlin basin this species has been recorded from the Condamine, Peel, Namoi, Macintyre and Cockburn rivers and in Boiling Down and Warialda Creeks. This is a disjunct distribution and the presence of Un-specked hardyheads seems to exclude this species. Where it does occur it is reported to be relatively common. [4] In the catchment of the Hunter River the Darling River hardyhead occurs between 50 and 330 metres (160 and 1,080 ft). [5]

Habitat and biology

The Darling River hardyhead occurs in slow-flowing, clear, shallow rivers and streams or among the aquatic vegetation at the margins of these waters. It will also occur in faster currents such as those that are found where a deeper pool drains. Their life history is almost unknown but small juvenile specimens have been collected in September. It has been reported to occur solitarily or in schools which can be formed of more than fifty fishes. In the Macintyre River, spawning seems to run from September to February. [4] What is known is that they form pairs to spawn and after mating the females lay the eggs among aquatic vegetation. [5]

Breeding and spawning occurs in the middle of summer. [6]

They are omnivorous with the bulk of their diet consisting of algae and insect larvae but gastropods, small crustaceans, worms and the eggs of fish have all been recorded as being consumed by this species. [5]

Conservation

The Darling River hardyhead is threatened by habitat degradation associated with agriculture and damaging factors include soil erosion, land clearance, the clearing of riverside vegetation, erosion of riverbanks caused by livestock, flood management and water abstraction. It is also threatened by introduced fish species such as mosquitofish ( Gambusia holbrooki ), goldfish, common carp and rainbow trout, the latter often stocked. [5]

Taxonomy

The Darling River hardyhead was previously misidentified as Craterocephalus eyresii and was not described until 1990 when Lucy Crowley and Walter Ivantsoff published a description of this species from a type locality of Cockburn River, Nemingha, New South Wales. [7] The populations of similar hardyheads in the Hunter catchment have been provisionally assigned to this species but may, on further investigation, prove to be a different species. [8]

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Old World silverside Family of fishes

The Old World silversides are a family, Atherinidae, of fish in the order Atheriniformes. They occur worldwide in tropical and temperate waters. About two-thirds of the species are marine, and the remainder live in fresh water. The 74 species are in 13 genera. The genus Craterocephalus is the most diverse with 25 species. Four genera are monotypic.

Hardyhead silverside Species of fish

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Agassiz's perchlet, also known as Agassiz's glass fish and the olive perchlet, is a species of ray-finned fish in the family Ambassidae. It is semi-transparent with dark scale edges forming a pattern over most of the body. It grows to a maximum of 7.5 cm. It is a macrophyte spawner with adhesive eggs. It is endemic to Australia. It was named for the zoologist Louis Agassiz.

<i>Craterocephalus</i> Genus of fishes

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The Finke River hardyhead is a species of fish in the family Atherinidae. It is endemic to the Finke River system in the Northern Territory, where it is widespread in open water or around aquatic vegetation. They occur in a wide range of salinity and pH and in Summer seek refuge in semi-permanent water holes. They are omnivores and feed on small crustaceans, insects, gastropods, polychaete worms, algae and fish eggs. This species shows a wide tolerance to temperature and salinity and is omnivore, probably spawning during warmer months. It was previously mis-identified as Craterocephalus eyresii.

Murray hardyhead Species of fish

The Murray hardyhead 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.

Glover's hardyhead is a species of fish in the family Atherinidae endemic to Dalhousie Springs in the Lake Eyre basin, Australia. The fish has a high thermal tolerance and inhabits warm, freshwater spring-fed pools and channels. It is listed as vulnerable on the IUCN Red List. The specific name honours John Glover (1935–1992) who was the Curator of Fishes at the South Australian Museum.

The Drysdale hardyhead is a species of fish in the family Atherinidae endemic to the Drysdale River in the Kimberley region of Australia. It is listed as near threatened on the IUCN Red List and rare under the Australian EPBC Act 1999. The specific name honours Ivantsoff's wife, Helena.

Kailola's hardyhead is a species of fish in the family Atherinidae endemic to Papua New Guinea. It reaches a maximum length of 6 cm. It inhabits shallow, clear creeks with gravel substrate. This species was described by Walter Ivantsoff, Lucy Crowley and Gerald R. Allen in 1987 with a type locality of a still backwater of Foasi Creek 3 kilometers west of Safia airstrip in Papua New Guinea. The specific name honours the Patricia J. Kailola, for her contribution to the knowledge of the ichthyology of Papua New Guinea.

Craterocephalus lentiginosus, the freckled hardyhead is a species of fish in the family Atherinidae endemic to the Kimberley region in the northwest of Australia. It is also called the Prince Regent hardyhead.

The Magela hardyhead or Mariana's Hardyhead, is a species of fish in the family Atherinidae endemic to Australia. It has a very restricted distribution, only found in the Alligator Rivers region of the Northern Territory where it inhabits shallow and fast-flowing freshwater creeks. The fish has a high thermal tolerance, like some other species in the genus Craterocephalus, and may tolerate water temperatures up to 39.5º. The specific name honours Walter Ivantsoff's daughter, Marian.

The Pima hardyhead is a species of silverside in the family Atherinidae which is endemic to Papua New Guinea. This species was described in 1991 by Walter Ivantsoff, Lucy Crowley and Gerald R. Allen with the type locality given as the junction of Pima and Tua rivers. It has not been recorded since the collection of the types.

Fly-specked hardyhead Species of fish

The fly-specked hardyhead is a species of fish in the family Atherinidae endemic and widespread in the freshwater streams of the Northern Territory down the east coast of Queensland into southern Queensland. It forms shoals in streams' shallows. It grows up to 10 cm in length.

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<i>Melanotaenia duboulayi</i> Species of fish

Melanotaenia duboulayi, the crimson-spotted rainbowfish, less commonly known as the Duboulay's rainbowfish, is a species of freshwater rainbowfish endemic to eastern Australia. M. duboulayi has also been kept in aquariums since the early 20th century, and is the original Australian rainbowfish.

<i>Fundulus nottii</i> Species of fish

Fundulus nottii, the bayou topminnow or southern starhead topminnow, is a fish of the family Fundulidae [1] found in the southeastern United States.

<i>Craterocephalus marjoriae</i> Species of fish

Craterocephalus marjoriae, commonly known as Marjorie's hardyhead or silverstreak hardyhead, is a species of fish in the family Atherinidae that is native to eastern Australia, namely central Queensland to northeastern New South Wales. Here it inhabits clear flowing streams and it is common among the vegetation in their margins. It prefers shallow water over streambeds consisting of sand or gravel. It forms shoals. They spawn on multiple occasions between September and January, although this peaks earlier in the season. They form pairs for spawning, the eggs being deposited on aquatic vegetation to which they adhere. The eggs are large measuring 1.15-1.25 mm in diameter and have adhesive filaments. The eggs hatch after around a week and the larvae measure about 5.7 mm standard length. Their diet consist mostly of aquatic insects and their larvae, small crustaceans, algae and fish eggs. This species was described by Gilbert P. Whitley in 1948 with the type locality given as Eidsvold on the Burnett River in Queensland. Whitley may have named this species in honour of his sister Marjorie Frewer.

Atherion elymus, the bearded silverside or pickleface hardyhead, is a species of silverside from the family Atherionidae. It is found in the western Pacific Ocean.

<i>Craterocephalus eyresii</i> Species of fish

Craterocephalus eyresii, the Lake Eyre hardyhead, is a species of freshwater silverside from the family Atherinidae which is endemic to the Lake Eyre basin in Australia.

References

  1. 1 2 Gilligan, D.; Moy, K. (2019). "Craterocephalus amniculus". IUCN Red List of Threatened Species . 2019: e.T5487A123377680. doi: 10.2305/IUCN.UK.2019-3.RLTS.T5487A123377680.en . Retrieved 16 November 2021.
  2. ↑ Christopher Scharpf & Kenneth J. Lazara (1 January 2019). "Order ATHERINIFORMES: Families ATHERINOPSIDAE, ATHERINIDAE and ATHERIONIDAE". The ETYFish Project Fish Name Etymology Database. Christopher Scharpf and Kenneth J. Lazara. Retrieved 21 July 2019.
  3. ↑ "Darling River Hardyhead in the Hunter River catchment". Department of Primary Industries, New South Wales Government. Retrieved 21 July 2019.
  4. 1 2 3 "Craterocephalus amniculus Crowley & Ivantsoff, 1992" (PDF). Fish of the Murray-Darling Basin. Murray Darling Basin Commission. 2007. Retrieved 21 July 2019.
  5. 1 2 3 4 5 Vanessa J. Thompson & Dianne J. Bray. "Craterocephalus amniculus". Fishes of Australia. Museums Victoria. Retrieved 21 July 2019.
  6. ↑ "Craterocephalus amniculus". Encyclopedia of Life. Retrieved 25 March 2013.
  7. ↑ Eschmeyer, William N.; Fricke, Ron & van der Laan, Richard (eds.). "Craterocephalus amnuculus". Catalog of Fishes . California Academy of Sciences . Retrieved 21 July 2019.
  8. ↑ Froese, Rainer and Pauly, Daniel, eds. (2019). "Craterocephalus amniculus" in FishBase . April 2019 version.
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