Lepidogalaxias

Lepidogalaxias
Drawings of male (top) and female (bottom) specimens of Lepidogalaxias
Scientific classification Edit this classification
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Division: Teleostei
Cohort: Euteleostei
Superorder: Lepidogalaxii
Order: Lepidogalaxiiformes
Family: Lepidogalaxiidae
Rosen, 1974
Genus: Lepidogalaxias
Mees, 1961
Species:
L. salamandroides
Binomial name
Lepidogalaxias salamandroides
Mees, 1961
Salamanderfish observed in habitat, 2023

Lepidogalaxias salamandroides is a species of small freshwater fish of Western Australia. Common names for this fish include salamanderfish and Shannon mudminnow. Although it is not a lungfish, it resembles lungfish in several respects, including its ability to survive dry seasons by burrowing into the sand. It is on the IUCN Red List as Endangered.

The salamanderfish belongs to Euteleostei, a clade of ray-finned fish. However, it is not considered to be closely related to other Euteleostei species. As such, it is placed in the monotypic superorder Lepidogalaxii.

Morphology

Lepidogalaxias salamandroides is small with females measuring up to 7 cm in length. This species has a slender, elongate and cylindrical body. The colour is brownish-green on the upper parts, silver-speckled and blotched on the sides, very pale below, and the fin membranes are transparent. The fish's eyes are fixed, lack eye muscles, and are covered by a secondary eyelid. To compensate, the fish is able to move its neck in any direction.

Biology

The salamanderfish spawn in winter when water levels are highest. Males have a uniquely modified anal fin used for internal fertilization. When not in use, the fin is folded strongly to the left or right and sheathed with a series of greatly enlarged scales. The females produce 100–400 eggs with a diameter of 1.1–1.3mm, which hatch into bottom-feeder larvae 5.5mm long. Larvae and juveniles grow rapidly to gain fat stores to survive the summer drought period. Individuals can reach up to 5 years of age.

The salamanderfish is carnivorous, mainly feeding on aquatic insect larvae. When their habitat dries, up they switch to atmospheric gas exchange via cutaneous respiration. The swim bladder, on the other hand, is not suitable for aerial respiration.

Range and habitat

It has a limited distribution in acidic pools of water in heathland peat flats of southwest Australia, between the Blackwood and Kent Rivers. This range is across a distance of 180 kilometres, in an area of Northcliffe, they are common in this region. Its habitat is semi-permanent water, small pools and streams that may be high in tannins and acidity (pH 3.0–6.5). They experience a range of water temperatures, daily changes of 16 to 32 degrees Celsius, in pools no deeper than 0.1 metres. The species rests on the bottom of the water using elongated pelvic and rounded caudal fins. These small and shallow pools may contain a population of around 150 individuals, are generally no larger than 600 square metres, and evaporate in the dry seasons. It is also unusual for its ability to survive desiccation by burrowing into sand, a process of aestivation, when the pools it lives in periodically evaporate.

Taxonomy

The species was first described in 1961 by Gerlof Mees. Mees identified the species as belonging to the family Galaxiidae, but its relationship to those species was in doubt. In 1991, Lepidogalaxias salamandroides was placed among the order Osmeriformes in the monotypic genus Lepidogalaxias and family Lepidogalaxiidae. Later analyses of molecular data uncovered that Lepidogalaxias is an old and isolated lineage and the sister group to all other Euteleostei species. As a result, Lepidogalaxias is placed as the sole member of the superorder Lepidogalaxii. The species is contained in the class Actinopterygii, ray-finned fish, and is sometimes placed in the order Salmoniformes.

It is sometimes named as the mud minnow, long-finned Galaxias, scaled galaxias, or dwarf pencilfish, however mud minnow usually refers to Galaxiella munda. A further list of names refer to L. salamandroides as salamanderfish of Western Australia, West Australian salamanderfish, salamander fish, salamanderfish, and Shannon mudminnow.

References

  1. 1 2 Morgan, D.L.; Beatty, S. (2019). "Lepidogalaxias salamandroides". IUCN Red List of Threatened Species. 2019 e.T11575A123378147. doi:10.2305/IUCN.UK.2019-3.RLTS.T11575A123378147.en. Retrieved 19 November 2021.
  2. 1 2 Baldisserotto, Bernardo; Urbinati, Elisabeth Criscuolo; Cyrino, J. E. P. (November 9, 2019). Biology and Physiology of Freshwater Neotropical Fish. Academic Press. p. 13. ISBN 978-0-12-815873-9.
  3. 1 2 McGrouther, M. (August 2005). "Salamanderfish: Lepidogalaxias salamandroides Mees, 1961". Find a Fish. Australian Museum, 2006. Retrieved 2008-10-26.
  4. 1 2 3 Berra, Tim M.; Pusey, Bradley J. (October 1997). "Threatened fishes of the world: Lepidogalaxias salamandroides Mees, 1961 (Lepidogalaxiidae)". Environmental Biology of Fishes. 50 (2): 201–202. Bibcode:1997EnvBF..50..201B. doi:10.1023/A:1007322606248. ISSN 1573-5133. S2CID 21584756.
  5. ↑ Lepidogalaxias salamandroides Mees - A Redescription, with Natural History Notes
  6. 1 2 Bray, Dianne. "Salamanderfish, Lepidogalaxias salamandroides". Fishes of Australia. Retrieved 30 January 2020.
  7. ↑ Pusey, B. J.; Stewart, T. (1989). "Internal fertilization in Lepidogalaxias salamandroides Mees (Pisces: Lepidogalaxiidae)". Zoological Journal of the Linnean Society. 97: 69–79. doi:10.1111/j.1096-3642.1989.tb00554.x.
  8. ↑ Lepidogalaxias salamandroides Mees — A Redescription, with Natural History Notes
  9. ↑ Implications of climate change on the aestivating Salamanderfish, Lepidogalaxias salamandroides Mees and the Black-stripe Minnow, Galaxiella nigrostriata Shipway
  10. 1 2 3 4 Berra, Tim M. (1995). "Lepidogalaxias_salamandroides". Version 01. The Tree of Life Web Project. Retrieved 2008-10-26.
  11. ↑ Mees, G. F. 1961. Description of a new fish of the family Galaxiidae from Western Australia. J. Roy. Soc. West. Aust. 44: 33–38.
  12. ↑ Li, J., Xia, R., McDowall, R. M. (2010): Phylogenetic position of the enigmatic Lepidogalaxias salamandroides with comment on the orders of lower euteleostean fishes. Molecular Phylogenetics and Evolution vol. 57: 932–936
  13. ↑ BETANCUR-R, Ricardo; WILEY, Edward O.; ARRATIA, Gloria (2017): Phylogenetic classification of bony fishes. BMC Evolutionary Biology, vol. 17
  14. 1 2 Gerald R. Allen, Norbert J. Cross & Douglass F. Hoese (27 Jun 2007). "Lepidogalaxias salamandroides Mees, 1961". Australian Faunal Directory. Department of the Environment, Water, Heritage and the Arts. Retrieved 2009-01-04.
  15. ↑ "Lepidogalaxias salamandroides". Integrated Taxonomic Information System. Retrieved 24 January 2006.
  16. 1 2 3 4 5 "Common Names of Lepidogalaxias salamandroides". Common name summary. FishBase. Retrieved 2009-01-05.
  17. ↑ Allen, G.R.; Midgley, S.H.; Allen, M. (2002). Field Guide to the Freshwater Fish of Australia. Perth: Western Australian Museum. p. 109. ISBN 0-7307-5486-3.

Further reading

Data related to Lepidogalaxiidae at Wikispecies