Guaranita Aylacostoma Snail (Aylacostoma guaraniticum)
This species was described in 1954, it inhabited highly oxygenated freshwater habitats near the Yacyretá-Apipé rapids in the high Paraná river at the border area between Argentinia and Paraguay.
It shared this habitat with two other species from the same genus, the Green Aylacostoma Snail (Aylacostoma chloroticum Hylton Scott) and the Stigmated Aylacostoma Snail (Aylacostoma stigmaticum Hylton Scott), all described by the same author at the same time.
The habitat of these three species was destroyed by the building of dams and by the filling of the Yacyretá reservoir in the early 1990s, leading to the extinction of at least two of the three species, including the Guaranita Aylacostoma Snail. [1]
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References:
[1] Roberto E. Vogler; Ariel A. Beltramino; Juana G. Peso; Alejandra Rumi: Threatened gastropods under the evolutionary genetic species concept: redescription and new species of the genus Aylacostoma (Gastropoda: Thiaridae) from High Paraná River (Argentina–Paraguay). Zoological Journal of the Linnean Society 172: 501-520. 2014
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edited: 24.11.2018