Potamolithus

Potamolithus rushii, from Pilsbry (1911).

Belongs within: Lithoglyphinae.

Potamolithus is a genus of freshwater snails with heavy, globose shells found on rocks in high energy environments in South America (Davis & Pons da Silva 1984).

Characters (from Davis & Pons da Silva 1984): Shell globose; operculum lacking internal pegs, projections, or calcium smears; radula with three or more pairs of basal cusps on rachidian tooth, some of the basal cusps arising from face of tooth, not lateral angle; left tentacle lacking hypertrophied cilia; nuchal node present on neck of female; pleuro-supraesophageal connective elongate; pedal tentacles absent; stomach lacking protuberance or fold; female genital aperture at posterolateral to anterior end of pallial oviduct, pallial oviducts closed, comprised of albumen and capsule glands merging directly into each other, seminal receptacle posterior to bursa copulatrix, sperm carried to bursa copulatrix in grooved channel open to pallial oviduct that is offset and folded around ventral pallial oviduct; penis slender, with protractile papilla, bearing one duct.

Potamolithus Pilsbry 1896 RGG06
    |--*P. rushii Pilsbry 1896 DPS84
    |--P. agapetus Pilsbry 1911 RGG06
    |--P. australis Biese 1944 RGG06
    |--P. buschii (Frauenfeld 1865) RGG06
    |--P. callosus Pilsbry 1925 RGG06
    |--P. catharinae Pilsbry 1911 RGG06
    |--P. concordianus Parodiz 1966 RGG06
    |--P. conicus (Brot 1867) RGG06
    |--P. dinochilus Pilsbry 1896 RGG06
    |--P. doeringi Pilsbry 1911 RGG06
    |--P. hidalgoi Pilsbry 1896 RGG06
    |--P. iheringi Pilsbry 1896 RGG06
    |--P. jacuhyensis Pilsbry 1899 RGG06
    |--P. karsticus Simone & Moracchioli 1994 S11
    |--P. lapidum (d’Orbigny 1835) RGG06 [=Lithoglyphus lapidum DPS84]
    |--P. microthauma Pilsbry 1896 RGG06
    |--P. orbignyi Pilsbry 1896 RGG06
    |--P. paranensis Pilsbry 1911 RGG06
    |--P. peristomatus (d’Orbigny 1835) RGG06
    |--P. petitianus d’Orbigny 1840 RGG06
    |--P. philipianus Pilsbry 1911 RGG06
    |--P. quadratus Pilsbry & Ihering 1911 RGG06
    |--P. ribeirensis Pilsbry 1911 S11
    |--P. simplex Pilsbry 1911 RGG06
    |--P. tricostatus (Brot 1967) RGG06
    |--P. troglobius Simone & Moracchioli 1994 S11
    |--P. valchetensis Miquel 1998 RGG06
    `--P. windhauseni (Parodiz 1961) RGG06

*Type species of generic name indicated

REFERENCES

[DPS84] Davis, G. M., & M. C. Pons da Silva. 1984. Potamolithus: morphology, convergence, and relationships among hydrobioid snails. Malacologia 25 (1): 73–108.

[RGG06] Rumi, A., D. E. Gutiérrez Gregoric, V. Núñez, I. I. César, M. A. Roche, M. P. Tassara, S. M. Martín & M. F. López Armengol. 2006. Freshwater Gastropoda from Argentina: species richness, distribution patterns, and an evaluation of endangered species. Malacologia 49 (1): 189–208.

[S11] Simone, L. R. L. 2011. Phylogeny of the Caenogastropoda (Mollusca), based on comparative morphology. Arquivos de Zoologia 42 (4): 161–323.