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Oreohelix cooperi

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Oreohelix cooperi

Vulnerable  (NatureServe)[1]
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Mollusca
Class: Gastropoda
Order: Stylommatophora
Family: Oreohelicidae
Genus: Oreohelix
Species:
O. cooperi
Binomial name
Oreohelix cooperi
(William Binney, 1858)

Oreohelix cooperi, also known as Cooper’s rocky mountainsnail or the Black Hills mountainsnail, is a critically endangered species of land snail that lives in the Rocky Mountain Ranges and Great Plains of North America.[2] Oreohelix cooperi is a hermaphroditic land snail that possesses low adult vagility and dispersal larvae stage.[2] Due to this spatial restriction, the decreased ability for O. cooperi to migrate leads it to being an endemic species to the Black Hills region.[3]

Physical description

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Oreohelix cooperi is in the phylum Mollusca, class Gastropoda, and order Stylommatophora. Within the Oreohelix genus, there are approximately 40-70 different species of land snail.[4] Characteristics of land snails include shells that vary in height and breadth, as well as vary in roundness and flatness.[5] The parts of the shell include a body whorl, spire, and apex.[5] The size of most large mountain land snails species is >5cm.[2] For O. cooperi, differences in shell size can be attributed to environmental factors, such as varying soil calcium concentrations.[6] Differences in size of the adults could be caused by differences in average temperature as well as shell density.[6] There is little genetic structure across its geographic range.[6]

Oreohelix cooperi is hermaphroditic as are most land snails.[6] As a hermaphrodite, they possess the reproductive organs of both males and females.[7] Additionally, O. cooperi are considered ovoviviparous, which means that after fertilization and until birth, the embryos continue to grow within the adult snail.[6]

Habitat and ecology

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Oreohelix cooperi lives in the Black Hills, east of the Rocky Mountains, in South Dakota and Wyoming.[2] The Black Hills region is characterized by a variety of habitats including prairie, deciduous forests, and coniferous forests.[2] This semi-arid region can maintain moisture throughout the year, which is facilitated by structural components such as down woody material.[8] The Black Hills receives its moisture from clouds coming from the west as the higher altitudes produce a rain shadow effect on the eastern slope of the range.[9] Oreohelix cooperi can occupy this region, as they prefer moist forest microhabitats with high calcium concentrations.[4]

Due to the fact that O. cooperi has low adult vagility and low dispersal at the larvae stage, they are likely to remain restricted in the Black Hills.[2] Due to this spatially restricted distribution, O. cooperi is considered an endemic species.[3] They are restricted to areas with a high concentrations of calcium, such as limestone and dolomite substrates, which allows them to maintain their shells.[3] Winters are cold, and summers are hot, as a consequence of continental climatic patterns.[9] O. cooperi is able to overwinter as well as the ability to undergo aestivation in the summer.[4] 

Threats and conservation

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Habitat loss is currently causing a decline in population sizes of Oreohelix cooperi.[3] Populations of O. cooperi are currently at risk due to the threats posed by fire, road-building, motorized recreation, and mining.[10] Management activities also pose a threat to populations of O. cooperi, as they could change the composition of cover provided by vegetation growth and litter, as well as ground temperature.[10] Additionally, it is also difficult to recolonize isolated populations of O. cooperi.[10] Climate change also poses a threat to O. cooperi populations, as it could lead to changes in moisture availability in the Black Forest region of South Dakota and Wyoming.[8]

Although there have been recommendations to list O. cooperi as a protected species under the Endangered Species Act (ESA), it is currently not listed.[3] Oreohelix cooperi is also not listed on the IUCN Red List. Due to habitat fragmentation and degradation, population numbers of O. cooperi continue to decline.[3]   

References

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  1. ^ "Oreohelix cooperi". NatureServe Explorer An online encyclopedia of life. 7.1. NatureServe. Retrieved 14 March 2025.
  2. ^ a b c d e f Weaver, Kathleen F.; Anderson, Tamara; Guralnick, Robert (2006). "Combining phylogenetic and ecological niche modeling approaches to determine distribution and historical biogeography of Black Hills mountain snails (Oreohelicidae)". Diversity and Distributions. 12 (6): 756–766. Bibcode:2006DivDi..12..756W. doi:10.1111/j.1472-4642.2006.00289.x. ISSN 1472-4642.
  3. ^ a b c d e f "Black Hills mountainsnail | Xerces Society". xerces.org. Retrieved 2025-02-16.
  4. ^ a b c Dempsey, Z. W.; Burg, T. M.; Goater, C. P. (2019). "Found, forgotten, and found again: Systematics and distribution of Cooper's Rocky Mountain Snail (Oreohelix cooperi) on a Sky Island in the Canadian Prairies". Canadian Journal of Zoology. 97 (9): 833–840. Bibcode:2019CaJZ...97..833D. doi:10.1139/cjz-2018-0118.
  5. ^ a b Eversham, B. (April 2018). "Identifying land snails" (PDF).
  6. ^ a b c d e Anderson, T. K.; Weaver, K. F.; Guralnick, R. P. (2007-05-01). "Variation in adult shell morphology and life-history traits in the land snail Oreohelix cooperi in relation to biotic and abiotic factors". Journal of Molluscan Studies. 73 (2): 129–137. doi:10.1093/mollus/eym006. ISSN 0260-1230.
  7. ^ Beese, K.; Beier, K.; Baur, B. (2006-03-01). "Coevolution of male and female reproductive traits in a simultaneously hermaphroditic land snail". Journal of Evolutionary Biology. 19 (2): 410–418. doi:10.1111/j.1420-9101.2005.01022.x. ISSN 1010-061X. PMID 16599917.
  8. ^ a b "Black Hills National Forest" (PDF). Forest Service U.S. Department of Agriculture. June 2022. Archived from the original (PDF) on October 23, 2023.
  9. ^ a b Ball, J.; Erickson, D.; Gerwulf, L. (1992). "The Black Hills Forest" (PDF). Habitats South Dakota Forests.
  10. ^ a b c Anderson, T. (19 April 2005). Oreohelix strigosa cooperi (Cooper's Rocky Mountain Snail): a technical conservation assessment (PDF) (Technical report). USDA Forest Service, Rocky Mountain Region.