Gammarus acherondytes, the Illinois cave amphipod, is a species of crustacean in the family Gammaridae. The crustacean is endemic to the Illinois Sinkhole Plain of Monroe County and St. Clair County, in southwestern Illinois, including Illinois Caverns State Natural Area.[1][2]

Gammarus acherondytes
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Malacostraca
Order: Amphipoda
Family: Gammaridae
Genus: Gammarus
Species:
G. acherondytes
Binomial name
Gammarus acherondytes
Hubricht & Mackin, 1940
Synonyms

Gammarus acheronytes (orthographic error)

Historically Gammarus acherondytes was known from six caves, but in a survey in 1995 the species was found at only three of the sites, with one further site inaccessible. This species occurs only in underground streams. It was first collected in 1938 and described as a new species in 1940. It has only been found in six cave streams, all lie within a 10-mile radius circle around Waterloo, Illinois, making this a very localized species. However, there is no evidence that these cave streams are currently interconnected. The main threat to the species is groundwater contamination.[1][2]

Description

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Gammarus acherondytes is a rather small crustacean with its most notable features being the light gray-blue color of its exoskeleton, and rather small eyes and no sensory organs on its second antenna.[3]

Range and habitat

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Gammarus acherondytes is native to underground streams and waterways in Illinois. It has been recorded from five cave streams located in the Monroe and St.Clair counties. Fogelpole Cave, Illinois Caverns, Krueger-Dry Run Cave, Madonnaville Cave, and Pautler Cave in Monroe County. Along with Stemler Cave in St. Clair County. With Pautler Cave being closed down by the landowner.[4] The largest population is recorded in the Illinois Caverns while no specimens were collected in Madonnaville and Stemler Cave since 1986 and 1965 respectively. Genetic evidence implies that none of these cave systems are interconnected due to the genomic pool of the populations being quite varied.[5]

Threats and conservation efforts

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Human pollution and runoff is the main threat to the species. With chemical pollution being the major threat to quality of water where they reside. Although research shows that Gammarus acherondytes breed all year-round. With juveniles constituting more than 50% of the population and strongly influence population density. Giving reason to believe that if they are allowed to remain undisturbed the population could feasibly bounce back to pre-pollutant levels.[6]

References

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  1. ^ a b c Crandall, K.; et al. (Inland Water Crustacean Specialist Group) (2002). "Gammarus acherondytes". IUCN Red List of Threatened Species. 2002: e.T40743A10361653. doi:10.2305/IUCN.UK.2002.RLTS.T40743A10361653.en. Retrieved 17 November 2021.
  2. ^ a b "Illinois Cave Amphipod, Gammarus acherondytes" (PDF). United States Fish and Wildlife Service. Retrieved 12 January 2019.
  3. ^ Webb, Donald W. (1995). "STATUS REPORT ON THE CAVE AMPHIPOD GAMMARUS ACHERONDYTES HUBRICHT AND MACKIN (CRUSTACEA: AMPHIPODA) IN ILLINOIS" (PDF). Illinois Natural History Survey. 22: 1–21 – via Illinois Digital Environment for Access to Learning and Scholarship.
  4. ^ Webb, Donald; Page, Lawrence; Taylor, Steven J.; Krejca, Jean K. (December 1998). "The Current Status and Habitats of the Illinois Cave Amphipod, Gammarus Acherondytes Hubrichts and Mackin (Crustacea: Amphipoda)". Journal of Cave and Karst Studies the National Speleological Society Bulletin. 60: 172–178.
  5. ^ Venarsky, M. P.; Anderson, F. E.; Wilhelm, F. M. (2008-04-05). "Population genetic study of the U.S. federally listed Illinois cave amphipod, Gammarus acherondytes". Conservation Genetics. 10 (4): 915–921. doi:10.1007/s10592-008-9579-0. ISSN 1566-0621. S2CID 22571861.
  6. ^ Venarsky, Michael P.; Wilhelm, Frank M.; Anderson, Frank E. (2007-01-01). "Conservation Strategies Supported by Non-Lethal Life History Sampling of the U.S. Federally Listed Illinois Cave Amphipod, Gammarus Acherondytes". Journal of Crustacean Biology. 27 (2): 202–211. doi:10.1651/s-2782.1. ISSN 0278-0372.
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