Potamolithus is a genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of small freshwater snail

Freshwater snail

A freshwater snail is one kind of freshwater mollusc, the other kind being freshwater clams and mussels, i.e. freshwater bivalves. Specifically a freshwater snail is a gastropod that lives in a watery non-marine habitat. The majority of freshwater gastropods have a shell, with very few exceptions....

s that have an operculum

Operculum (gastropod)

The operculum, meaning little lid, is a corneous or calcareous anatomical structure which exists in many groups of sea snails and freshwater snails, and also in a few groups of land snails...

, aquatic

Aquatic animal

An aquatic animal is an animal, either vertebrate or invertebrate, which lives in water for most or all of its life. It may breathe air or extract its oxygen from that dissolved in water through specialised organs called gills, or directly through its skin. Natural environments and the animals that...

 gastropod mollusks in the family Lithoglyphidae

Lithoglyphidae

Lithoglyphidae is a family of small freshwater snails with gills and an operculum, aquatic gastropod mollusks.This family is in the superfamily Rissooidea and in the clade Littorinimorpha .- Taxonomy :Taylor , Ponder & Warén and Kabat & Hershler considered this taxon as a subfamily...

.

Potamolithus was traditionally classified within the Hydrobiidae. However, anatomical study of Potamolithus by Davis & Pons da Silva (1984) showed its relationship with Lithoglyphus

Lithoglyphus

Lithoglyphus is a genus of freshwater snails with gills and an operculum, a gastropod mollusk in the family Lithoglyphidae.- Taxonomy :Lithoglyphus is the type genus of the family Lithoglyphidae....

, and it is now placed within the family Lithoglyphidae.

The first appearance of the name Potamolithus was in November 1896 as a nomen nudum

Nomen nudum

The phrase nomen nudum is a Latin term, meaning "naked name", used in taxonomy...

 (a bare name with no description or illustration). The genus was formally defined by Pilsbry in December 1896.

Distrubution

Potamolithus is the only genus of the family Lithoglyphidae in South America. Distribution of Potamolithus includes Argentina (22 species, 11 species are endemic to Argentina), Uruguay (17 species) and Brazil. Potamolithus is the largest genus (i.e. the one with the highest species richness

Species richness

Species richness is the number of different species in a given area. It is represented in equation form as S.Species richness is the fundamental unit in which to assess the homogeneity of an environment. Typically, species richness is used in conservation studies to determine the sensitivity of...

) of recent freshwater snails in Argentina and in Uruguay.

Species

Species within the genus Potamolithus include:

• Potamolithus agapetus Pilsbry, 1911
• Potamolithus bushii (Frauenfeld, 1865)
• Potamolithus callosus Pilsbry, 1925
• Potamolithus carinifer Pilsbry, 1911
• Potamolithus catharinae Pilsbry, 1911
• Potamolithus concordianus Parodiz, 1966
• Potamolithus conicus (Brot, 1867)
• Potamolithus dinochilus Pilsbry, 1896
• Potamolithus doeringi Pilsbry, 1911
• Potamolithus felipponei Ihering, 1910
• Potamolithus hidalgoi Pilsbry, 1896 - synonyms: Potamolithus microthauma Pilsbry, 1896; Potamolithus dinochilus Pilsbry, 1896; Potamolithus hatcheri Pilsbry, 1911
• Potamolithus iheringi Pilsbry, 1896
• Potamolithus karsticus Simone & Moracchioli, 1994
• Potamolithus lapidum (d'Orbigny, 1835) - synonyms: Potamolithus lapidum supersulcatus Pilsbry, 1896; Potamolithus paysanduanus Ihering, 1910; Potamolithus lapidum var. elatior Pilsbry, 1911; Potamolithus callosus Pilsbry, 1926
• Potamolithus microthauma Pilsbry, 1896
• Potamolithus orbignyi Pilsbry, 1896
• Potamolithus paranensis Pilsbry, 1911
• Potamolithus peristomatus (d'Orbigny, 1835)
• Potamolithus petitianus (d'Orbigny, 1840)
  • Potamolithus petitianus sykesii Pilsbry, 1896 - synonyms: Potamolithus bisinuatus bisinuatus Pilsbry, 1896; Potamolithus bisinuatus obsoletus Pilsbry, 1896; Potamolithus gracilis gracilis Pilsbry, 1896; Potamolithus gracilis viridis Pilsbry, 1896
• Potamolithus philipianus Pilsbry, 1911
• Potamolithus quadratus Pilsbry & Ihering, 1911
• Potamolithus rushii
  Potamolithus rushii
  Potamolithus rushii is a species of freshwater snail with an operculum, an aquatic gastropod mollusk in the family Lithoglyphidae.Potamolithus rushii is the type species of the genus Potamolithus....
  
  Pilsbry, 1896 - type genus
• Potamolithus ribeirensis Pilsbry, 1911
• Potamolithus simplex Pilsbry, 1911
• Potamolithus tricostatus (Brot, 1867)
• Potamolithus troglobius Simone & Moracchioli, 1994
• Potamolithus valchetensis Miquel, 1998

Ecology

Potamolithus species live in streams. Some species are subterranean

Subterranean

Subterranean or The Subterranean may refer to:* Subterranea , underground structures, both natural and man-madeIn literature:* The Subterraneans, a novella by Jack Kerouac...

, living in caves (for example Potamolithus troglobius and Potamolithus karsticus).

Further reading

• Bichuette M. E. (1998). "Distribuição e biologia de gastrópodes de água doce, gênero Potamolithus, no Vale do Alto Ribeira, São Paulo (Mollusca: Gastropoda: Hydrobiidae)". M. Sc. Thesis – Instituto de Biociências, Universidade de São Paulo, São Paulo, Brasil. 127 pp.
• López Armengol M. F. (1985). "Estudio sistemaco y bioecológico del género Potamolithus (Hydrobiidae) utilizando técnicas de taxonomía numérica Tesis Doctoral (N°. 455)". Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata.
• López Armengol M. F. & Darrigran G. (1998). "Distribución del género neotropical Potamolithus Pilsbry & Rush, 1896 (Gastropoda: Hydrobiidae) en el estuario del Río de la Plata". Iberus 16: 267-274.
• Parodiz J. J. (1965). "Relaciones y evidencias paleontológicas de Potamolithus". Comunicaciones de la Sociedad Malacológica del Uruguay 1: 273-278.