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Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Crustacea
Class: Malacostraca
Order: Amphipoda
Family: Allocrangonyctidae
Holsinger, 1989 [1]
Genus: Allocrangonyx
Schellenberg, 1936 [2]
  • Allocrangonyx pellucidus (Mackin, 1935)
  • Allocrangonyx hubrichti Holsinger, 1971

Allocrangonyx is a genus of troglobitic amphipod crustaceans from the South Central United States.[3] The two species are both listed as vulnerable on the IUCN Red List.[4][5] The animals are blind and unpigmented. During the male's development, the outer ramus of the third uropod differentiates into secondary segments and grows to a length greater than the animal's body length.[6]

Allocrangonyx pellucidus[edit]

Allocrangonyx pellucidus lives in springs adjacent to Turner Falls.

A. pellucidus, the "Oklahoma cave amphipod",[2] is known from caves and springs in the Arbuckle Mountains of Johnston, Murray and Pontotoc counties, Oklahoma.[7] The largest males reach 21.75 mm (0.856 in) long, while females reach 18 mm (0.71 in).[3]

Allocrangonyx hubrichti[edit]

A. hubrichti, the "Central Missouri cave amphipod"[2] or "Hubricht's long-tailed amphipod",[6] was thought for many years to be endemic to the state of Missouri, but specimens were discovered in 1996, 283 km (176 mi) away, in a water well near Romance, White County, Arkansas.[8] While the well is drilled into Pennsylvanian age sandstone, all previous records have been from Ordovician limestones and dolomitic rocks.[8]


  1. ^ "Allocrangonyctidae Holsinger, 1989". Integrated Taxonomic Information System. 
  2. ^ a b c "Allocrangonyx Schellenberg, 1936". Integrated Taxonomic Information System. 
  3. ^ a b John R. Holsinger (1971). "A new species of the subterranean amphipod genus Allocrangonyx (Gammaridae), with a redescription of the genus and remarks on its zoogeography". International Journal of Speleology. 3 (3/4): 317–331. doi:10.5038/1827-806x.3.3.11. 
  4. ^ Inland Water Crustacean Specialist Group (1996). "Allocrangonyx hubrichti". IUCN Red List of Threatened Species. Version 2009.2. International Union for Conservation of Nature. Retrieved April 14, 2010. 
  5. ^ Inland Water Crustacean Specialist Group (1996). "Allocrangonyx pellucidus". IUCN Red List of Threatened Species. Version 2009.2. International Union for Conservation of Nature. Retrieved April 14, 2010. 
  6. ^ a b Julian J. Lewis (October 2002). "Conservation assessment for Hubricht's long-tailed amphipod (Allocrangonyx hubrichti)" (PDF). USDA Forest Service. 
  7. ^ G. O. Graening; John R. Holsinger; Danté B. Fenolio; Elizabeth A. Bergey; Caryn C. Vaughn (2006). "Annotated checklist of the amphipod crustaceans of Oklahoma, with emphasis on groundwater habitats" (PDF). Proceedings of the Oklahoma Academy of Science. 86: 65–74. 
  8. ^ a b Henry W. Robison; John R. Holsinger (2000). "First record of the subterranean amphipod crustacean Allocrangonyx hubrichti (Allocrangonyctidae) in Arkansas" (PDF). Journal of the Arkansas Academy of Science. 54: 153.