Pachychilidae
Introduction '''Pachychilidae''', common name '''pachychilids''', is a taxonomic family of freshwater snails, gastropod molluscs in the clade Sorbeoconcha.
Distribution The global distribution of the family PachychilidaePachychilids are freshwater snails with a worldwide distribution in the tropics. Representatives are found in South and Central America, Africa, Madagascar, South and South-east Asia and tropical Australia (Queensland: Torres Strait Islands).
Description Pachychilids have an operculum, which is concentric and multispiral.
Ecology All species in the family inhabit freshwater except ''Faunus ater'', which is a brackish water snail found in estuaries and other coastal habitats. Pachychilids are either oviparous (lay eggs), ovoviviparous or viviparous (retain developing eggs and youngs in special incubatory structures).
Notes on the taxonomy The name is derived from a combination of the words 'pachy' (Greek = thick) and the suffix '-chilus' (Greek = Lip), meaning 'thick lipped' - with respect to the thickened aperture of the shell in some species. Most 20th-century authors did not recognize Pachychilidae as an independent family, but affiliated species under different groups, such as Thiaridae and Pleuroceridae. However, recent revisions based on molecular and morphological evidence have proven their independent and distinct status from the former. This family has no subfamilies (according to the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005).
Genera Shells of various pachychilid speciesGenera within the family Pachychilidae include:* † ''Bellatara'' Strand, 1928 - with only one species ''Bellatara janus'' (Mayer, 1870)* ''Brotia'' H. Adams, 1866 * ''Doryssa'' Swainson, 1840* † ''Eginea'' Pacaud & Harzhauser, 2012* ''Faunus'' de Montfort, 1810 with the only species ''Faunus ater'' (Linnaeus, 1758)* ''Jagora'' Köhler & Glaubrecht, 2003* † ''Jponsia'' Pacaud & Harzhauser, 2012* ''Madagasikara'' Köhler & Glaubrecht, 2010 - synonym: ''Melanatria'' Bowdich, 1822 auctt. * † ''Nodifaunus'' Olsson, 1944* ''Pachychilus'' I. Lea & H. C. Lea, 1851 - type genus of the family Pachychilidae* ''Paracrostoma'' Cossmann, 1900 * ''Potadoma'' Swainson, 1840* † ''Pseudobellardia'' Cox, 1931* ''Pseudopotamis'' Martens, 1894* ''Sulcospira'' Troschel, 1858 - synonym: ''Adamietta'' Brandt, 1974  * † ''Tinnyea'' Hantken, 1887* ''Tylomelania'' Sarasin & Sarasin, 1897* † ''Wingeastonia'' K. Martin, 1906;Genera brought into synonymy:* ''Acrostoma'' Brot, 1871: synonym of ''Paracrostoma'' Cossmann, 1900* ''Antimelania'' P. Fischer & Crosse, 1892: synonym of ''Brotia'' H. Adams, 1866* ''Brotella'' Rovereto, 1899: synonym of ''Paracrostoma'' Cossmann, 1900* Fauninae Cossmann, 1909 (subfamily) : synonym of ''Pachychilidae'' P. Fischer & Crosse, 1892* ''Melanatria'' Bowdich, 1822: synonym of ''Faunus'' Montfort, 1810* ''Oxymelania'' Crosse & P. Fischer, 1892: synonym of ''Pachychilus'' I. Lea & H. C. Lea, 1851* ''Pirena'' Lamarck, 1822: synonym of ''Faunus'' Montfort, 1810* ''Sphaeromelania'' Rovereto, 1899: synonym of ''Pachychilus'' I. Lea & H. C. Lea, 1851* ''Wanga'' Chen, 1943: synonym of ''Brotia'' H. Adams, 1866
Cladogram A cladogram based on sequences of mitochondrial 16S ribosomal RNA sequences showing phylogenic relations of Pachychilidae:
References
Further reading * Köhler F., von Rintelen T., Meyer A. & Glaubrecht M. (2004). "Multiple origin of viviparity in southeast Asian gastropods (Cerithioidea: Pachychilidae) and its evolutionary implications". ''Evolution'' '''58'''(10): 2215-2226..
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