Aylacostoma is a genus of tropical freshwater snails with an operculum. They are part of the family Hemisinidae, a group of aquatic gastropod molluscs. They are found in South and Central America. As a consequence of the Yacyretá Dam, two species are entirely extinct and another is extinct in the wild.[3][4]
| Aylacostoma | |
|---|---|
_-_Thiaridae_-_Mollusc_shell.jpeg)
| |
| Aylacostoma crenocarina | |
Scientific classification 
| |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Gastropoda |
| Subclass: | Caenogastropoda |
| Family: | Hemisinidae |
| Genus: | Aylacostoma Spix, 1827[1] |
| Type species | |
| Aylacostoma glabrum Spix, 1827
| |
| Diversity[2] | |
| 32 species | |
Species
editSpecies within genus Aylacostoma include:
- Aylacostoma brunneum Vogler & Peso, 2014
- Aylacostoma chloroticum Hylton-Scot, 1953
- Aylacostoma ci Simone, 2001
- Aylacostoma exoplicatum Simone, 2001
- Aylacostoma francanum (Ihering, 1909)[2]
- Aylacostoma glabrum Spix, 1827
- Aylacostoma guaraniticum Hylton-Scot, 1953
- Aylacostoma osculati (Villa, 1857) - synonym: Hemisinus osculati[5]
- Aylacostoma stigmaticum Hylton-Scot, 1953
- Aylacostoma tenuilabris (Reeve, 1860)
Distribution
editThe native distribution of this genus includes Central and South America.[2]
Life habits
editSome species in this genus used to live in areas of white water in the Yacyretá Rapids, Paraná River, feeding on the algae that grow attached to the rocks on the bottom. The water in the area is saturated with oxygen, from the fast-moving waters.[citation needed]
Aylacostoma is a parthenogenic species: the population consists of only females, which increase in number by asexual reproduction. The females give birth to a small number of larvae, no more than three, that are born very well developed, so they have the physical strength needed to attach to a rock and resist the strong current.[citation needed]
Conservation status
editWith the building in 1993 of the Yacyretá Dam, almost all the suitable habitat for Aylacostoma living in this region was flooded. Consequently, A. guaraniticum and A. stigmaticum became entirely extinct, A. brunneum extinct in the wild (survives in captivity), and A. chloroticum restricted to single small wild population and a captive "safety" population.[3][4] The captive populations of the last two species are jointly managed by the National University of Misiones and Bernardino Rivadavia Natural Sciences Museum.[3]
References
edit- ^ Spix J. B. von (1827). Testacea fluviatilia quae in itinere per Brasiliam annis MDCCCXVII-MDCCCXX. page 15.
- ^ a b c Paschoal L. R. P., Andrade D. d. P. & Cavallari D. C. (2013). "First record of Aylacostoma francana (Ihering, 1909) (Gastropoda, Thiaridae) in Minas Gerais state, Brazil". Biotemas 26(2): 277-281. doi:10.5007/2175-7925.2013v26n2p277.
- ^ a b c Vogler (2013). The Radula of the Extinct Freshwater Snail Aylacostoma stigmaticum (Caenofastropoda: Thiaridae) from Argentina and Paraguay. Malacologia 56 (1-2): 329-332.
- ^ a b Vogler, Beltramino, Strong & Rumi (2015). A phylogeographical perspective on the ex situ conservation of Aylacostoma (Thiaridae, Gastropoda) from the High Paraná River (Argentina–Paraguay). Zoological Journal of the Linnean Society 174(3): 487-499.
- ^ Pastorino, G.; Darrigan, G. (2011). "Aylacostoma osculati". IUCN Red List of Threatened Species. 2011: e.T189536A8745653. doi:10.2305/IUCN.UK.2011-2.RLTS.T189536A8745653.en. Retrieved 16 November 2021.
External links
edit
- Simone L. R. L. (2006). Land and freshwater molluscs of Brazil: an illustrated inventory on the Brazilian malacofauna, including neighbour regions of the South America, respect to the terrestrial and freshwater ecosystems. São Paulo: FAPESP, 390 pp.