Pulmonata or pulmonates, is an informal group (previously an order, and before that a subclass) of snails and slugs characterized by the ability to breathe air, by virtue of having a pallial lung instead of a gill, or gills. The group includes many land and freshwater families, and several marine families. The taxon Pulmonata as traditionally defined was found to be polyphyletic in a molecular study per Jörger et al., dating from 2010. Pulmonata are known from the Carboniferous Period to the present. Pulmonates have a single atrium and kidney, and a concentrated, symmetrical, nervous system. The mantle cavity is on the right side of the body, and lacks gills, instead being converted into a vascularised lung. Most species have a shell, but no operculum, although the group does also include several shell-less slugs. Pulmonates are hermaphroditic, and some groups possess love darts. Linnean taxonomy The taxonomy of this group according to the taxonomy of the Gastropoda (Ponder & Lindberg, 1997) was as follows: Order Pulmonata Cuvier in Blainville, 1814 - pulmonates Suborder Systellommatophora Pilsbry, 1948 Superfamily Onchidioidea Rafinesque, 1815 Superfamily Otinoidea H. & A. Adams, 1855 Superfamily Rathouisioidea Sarasin, 1889 Suborder Basommatophora Keferstein in Bronn, 1864 - freshwater pulmonates, pond snails Superfamily Acroloxoidea Thiele, 1931 Superfamily Amphiboloidea J.E. Gray, 1840 Superfamily Chilinoidea H. & A. Adams, 1855 Superfamily Glacidorboidea Ponder, 1986 Superfamily Lymnaeoidea Rafinesque, 1815 Superfamily Planorboidea Rafinesque, 1815 Superfamily Siphonarioidea J.E. Gray, 1840 Suborder Eupulmonata Haszprunar & Huber, 1990 Infraorder Acteophila Dall, 1885 = formerly Archaeopulmonata Superfamily Melampoidea Stimpson, 1851 Infraorder Trimusculiformes Minichev & Starobogatov, 1975 Superfamily Trimusculoidea Zilch, 1959 Infraorder Stylommatophora A. Schmidt, 1856 - land snails Subinfraorder Orthurethra Superfamily Achatinelloidea Gulick, 1873 Superfamily Cochlicopoidea Pilsbry, 1900 Superfamily Partuloidea Pilsbry, 1900 Superfamily Pupilloidea Turton, 1831 Subinfraorder Sigmurethra Superfamily Acavoidea Pilsbry, 1895 Superfamily Achatinoidea Swainson, 1840 Superfamily Aillyoidea Baker, 1960 Superfamily Arionoidea J.E. Gray in Turnton, 1840 Superfamily Buliminoidea Clessin, 1879 Superfamily Camaenoidea Pilsbry, 1895 Superfamily Clausilioidea Mörch, 1864 Superfamily Dyakioidea Gude & Woodward, 1921 Superfamily Gastrodontoidea Tryon, 1866 Superfamily Helicoidea Rafinesque, 1815 Superfamily Helixarionoidea Bourguignat, 1877 Superfamily Limacoidea Rafinesque, 1815 Superfamily Oleacinoidea H. & A. Adams, 1855 Superfamily Orthalicoidea Albers-Martens, 1860 Superfamily Plectopylidoidea Moellendorf, 1900 Superfamily Polygyroidea Pilsbry, 1894 Superfamily Punctoidea Morse, 1864 Superfamily Rhytidoidea Pilsbry, 1893 Superfamily Sagdidoidera Pilsbry, 1895 Superfamily Staffordioidea Thiele, 1931 Superfamily Streptaxoidea J.E. Gray, 1806 Superfamily Strophocheiloidea Thiele, 1926 Superfamily Trigonochlamydoidea Hese, 1882 Superfamily Zonitoidea Mörch, 1864 ? Superfamily Athoracophoroidea P. Fischer,