Editing Digenea (section)

==Evolution==
The evolutionary origins of the Digenea have been debated for some time, but there appears general agreement that the proto-digenean was a parasite of a mollusc, possibly of the mantle cavity.  Evidence for this comes from the ubiquity of molluscs as first intermediate hosts for digeneans, and the fact that most aspidogastreans (the sister group to the Digenea) also have mollusc associations.  It is thought that the early trematodes (the collective name for digeneans and aspidogastreans) likely evolved from rhabdocoel [[turbellaria]]ns that colonised the open mantle cavity of early molluscs.

It is likely that more complex life cycles evolved through a process of terminal addition, whereby digeneans survived predation of their mollusc host, probably by a fish.  Other hosts were added by the same process until the modern bewildering diversity of life cycle patterns developed.

===Important families===
Digenea includes about 80 families.<ref>Olson P. D., Cribb T. H., Tkach V. V., Bray R. A. & Littlewood D. T. J. (2003). "Phylogeny and classification of the Digenea (Platyhelminthes: Trematoda)". ''International Journal for Parasitology'' '''33'''(7): 733–755. {{doi|10.1016/S0020-7519(03)00049-3}}</ref> They are listed below, organised by order.

'''Digenea'''
*[[Diplostomida]]
**Suborder Diplostomata
***Superfamily Brachylaimoidea <small>Joyeux & Foley, 1930</small>
****[[Brachylaimidae]] <small>Joyeux & Foley, 1930</small>
****[[Leucochloridiidae]] <small>Poche, 1907</small>
***Superfamily Diplostomoidea <small>Poirier, 1886</small>
****[[Brauninidae]] <small>Wolf, 1903</small>
****[[Cyathocotylidae]] <small>Mühling, 1898</small>
****[[Diplostomidae]] <small>Poirier, 1886</small>
****[[Proterodiplostomidae]] <small>Dubois, 1936</small>
****[[Strigeidae]] <small>Railliet, 1919</small>
***Superfamily Schistosomatoidea <small>Stiles & Hassall, 1898</small>
****[[Aporocotylidae]] <small>Odhner, 1912</small>
****[[Schistosomatidae]] <small>Stiles & Hassall, 1898</small>
****[[Spirorchiidae]] <small>Stunkard, 1921</small>
*[[Plagiorchiida]]
**Apocreadiata
***Apocreadioidea <small>Skrjabin, 1942</small>
****[[Apocreadiidae]] <small>Skrjabin, 1942</small>
**Bivesiculata
***Bivesiculoidea
****[[Bivesiculidae]] <small>Yamaguti, 1934</small>
**Bucephalata
***Bucephaloidea <small>Poche, 1907</small>
****[[Bucephalidae]] <small>Poche, 1907</small>
****[[Nuitrematidae]] <small>Kurochkin, 1975</small>
***Gymnophalloidea <small>Odhner, 1905</small>
****[[Botulisaccidae]] <small>Yamaguti, 1971</small>
****[[Fellodistomidae]] <small>Nicoll, 1909</small>
****[[Gymnophallidae]] <small>Odhner, 1905</small>
****[[Tandanicolidae]] <small>Johnston, 1927</small>
**Echinostomata
***Echinostomatoidea <small>Looss, 1902</small>
****[[Calycodidae]] <small>[[Robert-Philippe Dollfus|Dollfus]], 1929</small>
****[[Cyclocoelidae]] <small>Stossich, 1902</small>
****[[Echinochasmidae]] <small>Odhner, 1910</small>
****[[Echinostomatidae]] <small>Looss, 1899</small>
****[[Eucotylidae]] <small>Cohn, 1904</small>
****[[Fasciolidae]] <small>Railliet, 1895</small>
****[[Himasthlidae]] <small>Odhner, 1910</small>
****[[Philophthalmidae]] <small>Looss, 1899</small>
****[[Psilostomidae]] <small>Looss, 1900</small>
****[[Rhytidodidae]] <small>Odhner, 1926</small>
****[[Typhlocoelidae]] <small>Harrah, 1922</small>
**Haplosplanchnata
***Haplosplanchnoidea <small>Poche, 1925</small>
****[[Haplosplanchnidae]] <small>Poche, 1926</small>
**Hemiurata
***Azygioidea <small>Lühe, 1909</small>
****[[Azygiidae]] <small>Lühe, 1909</small>
***Hemiuroidea <small>Looss, 1899</small>
****[[Accacoeliidae]] <small>Odhner, 1911</small>
****[[Bathycotylidae]] <small>[[Robert-Philippe Dollfus|Dollfus]], 1932</small>
****[[Derogenidae]] <small>Nicoll, 1910</small>
****[[Dictysarcidae]] <small>Skrjabin & Guschanskaja, 1955</small>
****[[Didymozoidae]] <small>Monticelli, 1888</small>
****[[Gonocercidae]] <small>Skrjabin & Guschanskaja, 1955</small>
****[[Hemiuridae]] <small>Looss, 1899</small>
****[[Hirudinellidae]] <small>[[Robert-Philippe Dollfus|Dollfus]], 1932</small>
****[[Isoparorchiidae]] <small>Travassos, 1922</small>
****[[Lecithasteridae]] <small>Odhner, 1905</small>
****[[Ptychogonimidae]] <small>[[Robert-Philippe Dollfus|Dollfus]], 1937</small>
****[[Sclerodistomidae]] <small>Odhner, 1927</small>
****[[Sclerodistomoididae]] <small>Gibson & Bray, 1979</small>
****[[Syncoeliidae]] <small>Looss, 1899</small>
**Heronimata
***Heronimoidea <small>Ward, 1918</small>
****[[Heronimidae]] <small>Ward, 1918</small>
**Lepocreadiata
***Lepocreadioidea <small>Odhner, 1905</small>
****[[Aephnidiogenidae]] <small>Yamaguti, 1934</small>
****[[Deropristidae]] <small>Cable & Hunninen, 1942</small>
****[[Enenteridae]] <small>Yamaguti, 1958</small>
****[[Gorgocephalidae]] <small>Manter, 1966</small>
****[[Gyliauchenidae]] <small>Fukui, 1929</small>
****[[Lepidapedidae]] <small>Yamaguti, 1958</small>
****[[Lepocreadiidae]] <small>Odhner, 1905</small>
****[[Liliatrematidae]] <small>Gubanov, 1953</small>
**Monorchiata
***Monorchioidea <small>Odhner, 1911</small>
****[[Lissorchiidae]] <small>Magath, 1917</small>
****[[Monorchiidae]] <small>Odhner, 1911</small>
**Opisthorchiata
***Opisthorchioidea <small>Braun, 1901</small>
****[[Cryptogonimidae]] <small>Ward, 1917</small>
****[[Heterophyidae]] <small>Leiper, 1909</small>
****[[Opisthorchiidae]] <small>Looss, 1899</small>
**Pronocephalata
***Paramphistomoidea <small>Fischoeder, 1901</small>
****[[Cladorchiidae]] <small>Fischoeder, 1901</small>
****[[Mesometridae]] <small>Poche, 1926</small>
****[[Microscaphidiidae]] <small>Looss, 1900</small>
****[[Paramphistomidae]] <small>Fischoeder, 1901</small>
***Pronocephaloidea <small>Looss, 1899</small>
****[[Labicolidae]] <small>Blair, 1979</small>
****[[Notocotylidae]] <small>Lühe, 1909</small>
****[[Nudacotylidae]] <small>Barker, 1916</small>
****[[Opisthotrematidae]] <small>Poche, 1926</small>
****[[Pronocephalidae]] <small>Looss, 1899</small>
****[[Rhabdiopoeidae]] <small>Poche, 1926</small>
**Transversotremata
***Transversotrematoidea <small>Witenberg, 1944</small>
****[[Transversotrematidae]] <small>Witenberg, 1944</small>
**Xiphidiata
***Allocreadioidea <small>Looss, 1902</small>
****[[Acanthocolpidae]] <small>Lühe, 1906</small>
****[[Allocreadiidae]] <small>Looss, 1902</small>
****[[Batrachotrematidae]] <small>[[Robert-Philippe Dollfus|Dollfus]] & Williams, 1966</small>
****[[Brachycladiidae]] <small>Odhner, 1905</small>
****[[Opecoelidae]] <small>Ozaki, 1925</small>
***Gorgoderoidea <small>Looss, 1901</small>
****[[Callodistomidae]] <small>Odhner, 1910</small>
****[[Dicrocoeliidae]] <small>Looss, 1899</small>
****[[Gorgoderidae]] <small>Looss, 1899</small>
***Haploporoidea <small>Nicoll, 1914</small>
****[[Atractotrematidae]] <small>Yamaguti, 1939</small>
****[[Haploporidae]] <small>Nicoll, 1914</small>
***Microphalloidea <small>Ward, 1901</small>
****[[Diplangidae]] <small>Yamaguti, 1971</small>
****[[Exotidendriidae]] <small>Mehra, 1935</small>
****[[Faustulidae]] <small>Poche, 1926</small>
****[[Microphallidae]] <small>Ward, 1901</small>
****[[Pachypsolidae]] <small>Yamaguti, 1958</small>
****[[Phaneropsolidae]] <small>Mehra, 1935</small>
****[[Pleurogenidae]] <small>Looss, 1899</small>
****[[Prosthogonimidae]] <small>Lühe, 1909</small>
****[[Renicolidae]] <small>[[Robert-Philippe Dollfus|Dollfus]], 1939</small>
****[[Zoogonidae]] <small>Odhner, 1902</small>
***Plagiorchioidea <small>Lühe, 1901</small>
****[[Auridistomidae]] <small>Lühe, 1901</small>
****[[Brachycoeliidae]] <small>Looss, 1899</small>
****[[Cephalogonimidae]] <small>Looss, 1899</small>
****[[Choanocotylidae]] <small>Jue Sue & Platt, 1998</small>
****[[Echinoporidae]] <small>Krasnolobova & Timofeeva, 1965</small>
****[[Encyclometridae]] <small>Mehra, 1931</small>
****[[Leptophallidae]] <small>Dayal, 1938</small>
****[[Macroderoididae]] <small>McMullen, 1937</small>
****[[Meristocotylidae]] <small>Fischthal & Kuntz, 1981</small>
****[[Ocadiatrematidae]] <small>Fischthal & Kuntz, 1981</small>
****[[Orientocreadiidae]] <small>Yamaguti, 1958</small>
****[[Plagiorchiidae]] <small>Lühe, 1901</small>
****[[Styphlotrematidae]] <small>Baer, 1924</small>
****[[Telorchiidae]] <small>Looss, 1899</small>
****[[Thrinascotrematidae]] <small>Jue Sue & Platt, 1999</small>
****[[Urotrematidae]] <small>Poche, 1926</small>