Euastacus

Euastacus is a genus of freshwater crayfish known as "spiny crayfish". They are found in the south-east of the Australian mainland, along with another genus of crayfish, Cherax. Both genera are members of the family Parastacidae, a family of freshwater crayfish restricted to the Southern Hemisphere.

Euastacus
Euastacus spinifer
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Crustacea
Class: Malacostraca
Order: Decapoda
Family: Parastacidae
Genus: Euastacus
Clark, 1936
Type species
Euastacus elongatus
Clark, 1941

Euastacus crayfish are distinguished from the smooth-shelled Cherax species by the short robust spikes on their claws and carapace, and frequently, their larger size. Many Euastacus species grow to a relatively large size, with the Murray River crayfish (Euastacus armatus) being the second largest freshwater crayfish species in the world. (The largest freshwater crayfish in the world is the Tasmanian giant freshwater crayfish (Astacopsis gouldi), found on the Australian island of Tasmania, and the genus Astacopsis is now known to be a very closely related sister genus to Euastacus.)

The genera Cherax and Euastacus continue a trend present in many Australian native freshwater fish genera of speciation into generalist lowland and specialist upland species. Generally, Cherax species inhabit lowland rivers at low to medium altitudes and swamps and ephemeral waters in inland areas of Australia including the Murray-Darling Basin. Conversely, Euastacus species are only found in permanent waters and generally inhabit upland rivers at medium to high altitudes in the Murray-Darling Basin as well as many easterly and southerly flowing coastal river systems. The partial exceptions to this are:

  • the Murray River crayfish which was originally found along the entire length of the Murray River in addition to many upland habitats, and is still found in the middle reaches of the Murray River
  • the Glenelg Spiny Crayfish (Eustacus bispinosus), found (or formerly found) in lowland areas of the Glenelg River system and Eight Mile Creek/Ewen Ponds system [1]
  • the Gippsland Crayfish (Euastacus kershawi), found in lowland areas of some streams in the Gippsland area.

Even when found in lowland habitats, these several more adaptable Euastacus crayfish are still highly dependent on reliable flows and good water quality, with good dissolved oxygen levels and low salinity. In contrast to Cherax (yabby) species, Euastacus species are unable to survive drying of their habitats.

The genus Cherax has a far wider distribution than the genus Euastacus, and is found in many parts of Australia including south-western Australia. The genus Euastacus is restricted to the south-east of the Australian mainland. There is a high degree of endemism in Euastacus species in coastal river systems, with many species restricted to single river or creek catchment. Euastacus species occur in several upland reservoirs.

Euastacus species are extremely slow growing, long-lived (possibly 40+ years in some species), and late to reach sexual maturity. These biological characteristics make Euastacus species vulnerable to environmental disturbances and essentially unable to support to catch-and-kill fisheries.

Euastacus sp.

Species

Of the 50 species in the genus Euastacus,[2][3] 17 are on the IUCN Red List as critically endangered (CR), 17 are endangered (EN), 5 vulnerable (VU), 1 near threatened (NT), 8 least concern (LC) and 1 is data deficient (DD):

References
  1. Australian Government Department of Sustainability, Environment, Water (2011). "Listing Advice for Euastacus bispinosus" (PDF). Retrieved 20 April 2011.
  2. James W. Fetzner Jr. (14 January 2008). "Euastacus". Crayfish Taxon Browser. Carnegie Museum of Natural History. Retrieved 10 March 2010.
  3. Jason Coughran; Robert B. McCormack (2011). "Euastacus morgani sp. n., a new spiny crayfish (Crustacea, Decapoda, Parastacidae) from the highland rainforests of eastern New South Wales, Australia". ZooKeys. 85: 17–26. doi:10.3897/zookeys.85.1237. PMC 3082992. PMID 21594095.
  4. N. Alves; J. Coughran; J. Furse & S. Lawler (2010). "Euastacus armatus". IUCN Red List of Threatened Species. 2010. Retrieved 25 August 2011.CS1 maint: ref=harv (link)
  5. J. Furse & J. Cochran (2010). "Euastacus australasiensis". IUCN Red List of Threatened Species. 2010. Retrieved 25 August 2011.CS1 maint: ref=harv (link)
  6. J. Furse & J. Cochran (2010). "Euastacus balanesis". IUCN Red List of Threatened Species. 2010. Retrieved 25 August 2011.CS1 maint: ref=harv (link)
  7. J. Furse; J. Cochran & S. Lawler (2010). "Euastacus bidawalis". IUCN Red List of Threatened Species. 2010. Retrieved 25 August 2011.CS1 maint: ref=harv (link)
  8. J. Furse & J. Cochran (2010). "Euastacus bindal". IUCN Red List of Threatened Species. 2010. Retrieved 25 August 2011.CS1 maint: ref=harv (link)
  9. J. Furse & J. Cochran (2010). "Euastacus bispinosus". IUCN Red List of Threatened Species. 2010. Retrieved 25 August 2011.CS1 maint: ref=harv (link)
  10. J. Furse & J. Cochran (2010). "Euastacus brachythorax". IUCN Red List of Threatened Species. 2010. Retrieved 25 August 2011.CS1 maint: ref=harv (link)
  11. J. Furse & J. Cochran (2010). "Euastacus clarkae". IUCN Red List of Threatened Species. 2010. Retrieved 25 August 2011.CS1 maint: ref=harv (link)
  12. J. Furse & J. Cochran (2010). "Euastacus claytoni". IUCN Red List of Threatened Species. 2010. Retrieved 25 August 2011.CS1 maint: ref=harv (link)
  13. J. Furse; J. Cochran & S. Lawler (2010). "Euastacus crassus". IUCN Red List of Threatened Species. 2010. Retrieved 25 August 2011.CS1 maint: ref=harv (link)
  14. J. Furse & J. Cochran (2010). "Euastacus dalagarbe". IUCN Red List of Threatened Species. 2010. Retrieved 25 August 2011.CS1 maint: ref=harv (link)
  15. J. Furse & J. Cochran (2010). "Euastacus dangadi". IUCN Red List of Threatened Species. 2010. Retrieved 25 August 2011.CS1 maint: ref=harv (link)
  16. J. Furse & J. Cochran (2010). "Euastacus dharawalus". IUCN Red List of Threatened Species. 2010. Retrieved 25 August 2011.CS1 maint: ref=harv (link)
  17. J. Furse; J. Cochran & S. Lawler (2010). "Euastacus diversus". IUCN Red List of Threatened Species. 2010. Retrieved 25 August 2011.CS1 maint: ref=harv (link)
  18. J. Furse & J. Cochran (2010). "Euastacus eungella". IUCN Red List of Threatened Species. 2010. Retrieved 25 August 2011.CS1 maint: ref=harv (link)
  19. J. Furse & J. Cochran (2010). "Euastacus fleckeri". IUCN Red List of Threatened Species. 2010. Retrieved 25 August 2011.CS1 maint: ref=harv (link)
  20. J. Furse & J. Cochran (2010). "Euastacus gamilaroi". IUCN Red List of Threatened Species. 2010. Retrieved 25 August 2011.CS1 maint: ref=harv (link)
  21. J. Furse & J. Cochran (2010). "Euastacus girurmulayn". IUCN Red List of Threatened Species. 2010. Retrieved 25 August 2011.CS1 maint: ref=harv (link)
  22. J. Furse & J. Cochran (2010). "Euastacus gumar". IUCN Red List of Threatened Species. 2010. Retrieved 25 August 2011.CS1 maint: ref=harv (link)
  23. J. Furse & J. Cochran (2010). "Euastacus guruhgi". IUCN Red List of Threatened Species. 2010. Retrieved 25 August 2011.CS1 maint: ref=harv (link)
  24. J. Furse & J. Cochran (2010). "Euastacus guwinus". IUCN Red List of Threatened Species. 2010. Retrieved 25 August 2011.CS1 maint: ref=harv (link)
  25. "Euastacus hirsutus". IUCN Red List of Threatened Species. 2010. 2010. Retrieved 25 August 2011.CS1 maint: ref=harv (link)
  26. J. Furse & J. Cochran (2010). "Euastacus hystricosus". IUCN Red List of Threatened Species. 2010. Retrieved 25 August 2011.CS1 maint: ref=harv (link)
  27. J. Furse & J. Cochran (2010). "Euastacus jagabar". IUCN Red List of Threatened Species. 2010. Retrieved 25 August 2011.CS1 maint: ref=harv (link)
  28. J. Cochran & J. Furse (2010). "Euastacus jagara". IUCN Red List of Threatened Species. 2010. Retrieved 25 August 2011.CS1 maint: ref=harv (link)
  29. J. Cochran; J. Furse & S. Lawler (2010). "Euastacus kershawi". IUCN Red List of Threatened Species. 2010. Retrieved 25 August 2011.CS1 maint: ref=harv (link)
  30. J. Cochran & J. Furse (2010). "Euastacus maccai". IUCN Red List of Threatened Species. 2010. Retrieved 25 August 2011.CS1 maint: ref=harv (link)
  31. J. Cochran & J. Furse (2010). "Euastacus maidae". IUCN Red List of Threatened Species. 2010. Retrieved 25 August 2011.CS1 maint: ref=harv (link)
  32. J. Cochran & J. Furse (2010). "Euastacus mirangudjin". IUCN Red List of Threatened Species. 2010. Retrieved 25 August 2011.CS1 maint: ref=harv (link)
  33. J. Cochran & J. Furse (2010). "Euastacus monteithorum". IUCN Red List of Threatened Species. 2010. Retrieved 25 August 2011.CS1 maint: ref=harv (link)
  34. J. Cochran & J. Furse (2010). "Euastacus neodiversus". IUCN Red List of Threatened Species. 2010. Retrieved 25 August 2011.CS1 maint: ref=harv (link)
  35. J. Cochran & J. Furse (2010). "Euastacus neohirsutus". IUCN Red List of Threatened Species. 2010. Retrieved 25 August 2011.CS1 maint: ref=harv (link)
  36. J. Cochran & J. Furse (2010). "Euastacus pilosus". IUCN Red List of Threatened Species. 2010. Retrieved 25 August 2011.CS1 maint: ref=harv (link)
  37. J. Cochran & J. Furse (2010). "Euastacus polysetosus". IUCN Red List of Threatened Species. 2010. Retrieved 25 August 2011.CS1 maint: ref=harv (link)
  38. J. Cochran & J. Furse (2010). "Euastacus reductus". IUCN Red List of Threatened Species. 2010. Retrieved 25 August 2011.CS1 maint: ref=harv (link)
  39. J. Cochran; J. Furse & S. Lawler (2010). "Euastacus rieki". IUCN Red List of Threatened Species. 2010. Retrieved 25 August 2011.CS1 maint: ref=harv (link)
  40. J. Cochran & J. Furse (2010). "Euastacus robertsi". IUCN Red List of Threatened Species. 2010. Retrieved 25 August 2011.CS1 maint: ref=harv (link)
  41. J. Cochran & J. Furse (2010). "Euastacus setosus". IUCN Red List of Threatened Species. 2010. Retrieved 25 August 2011.CS1 maint: ref=harv (link)
  42. J. Cochran & J. Furse (2010). "Euastacus simplex". IUCN Red List of Threatened Species. 2010. Retrieved 25 August 2011.CS1 maint: ref=harv (link)
  43. J. Cochran & J. Furse (2010). "Euastacus spinichelatus". IUCN Red List of Threatened Species. 2010. Retrieved 25 August 2011.CS1 maint: ref=harv (link)
  44. J. Cochran & J. Furse (2010). "Euastacus spinifer". IUCN Red List of Threatened Species. 2010. Retrieved 25 August 2011.CS1 maint: ref=harv (link)
  45. J. Furse & J. Cochran (2010). "Euastacus sulcatus". IUCN Red List of Threatened Species. 2010. Retrieved 25 August 2011.CS1 maint: ref=harv (link)
  46. J. Cochran & J. Furse (2010). "Euastacus suttoni". IUCN Red List of Threatened Species. 2010. Retrieved 25 August 2011.CS1 maint: ref=harv (link)
  47. J. Cochran & J. Furse (2010). "Euastacus urospinosus". IUCN Red List of Threatened Species. 2010. Retrieved 25 August 2011.CS1 maint: ref=harv (link)
  48. J. Cochran & J. Furse (2010). "Euastacus valentulus". IUCN Red List of Threatened Species. 2010. Retrieved 25 August 2011.CS1 maint: ref=harv (link)
  49. J. Cochran; J. Furse & S. Lawler (2010). "Euastacus wiowuru". IUCN Red List of Threatened Species. 2010. Retrieved 25 August 2011.CS1 maint: ref=harv (link)
  50. J. Cochran & J. Furse (2010). "Euastacus yanga". IUCN Red List of Threatened Species. 2010. Retrieved 25 August 2011.CS1 maint: ref=harv (link)
  51. J. Cochran & J. Furse (2010). "Euastacus yarreansis". IUCN Red List of Threatened Species. 2010. Retrieved 25 August 2011.CS1 maint: ref=harv (link)
  52. J. Cochran & J. Furse (2010). "Euastacus yigara". IUCN Red List of Threatened Species. 2010. Retrieved 25 August 2011.CS1 maint: ref=harv (link)
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