Encyonema

Encyonema is a genus of asymmetric biraphid diatoms belonging to the family Cymbellaceae. This genus is characterized by its curved dorsal edge and ventrally-deflected distal raphe ends. Encyonema contains mostly freshwater species, though there are a few marine exceptions. First described by German phycologist and botanist Friedrich T. Kützing in his 1833 publication "Synopsis diatomearum," this genus has over 400 described specific and infraspecific taxa and new species are still being described today. The genus underwent significant revision in the 1980s and 90s, resulting in the reclassification of multiple species as belonging to Encyonema that were previously grouped in the Cymbella genus. K. Krammer and Round et al. were the first to formally separate Encyonema species from Cymbella, citing differences in raphe orientation as well as striae and plastid structures.

The genus has cosmopolitan distribution, primarily being found in benthic freshwater habitats with low electrolyte content. Many Encyonema species are capable of producing mucilaginous sheaths, with some forming colonies within mucilage tubes. This genus exhibits a broad size range, with species like E. reichardtii being as small as 9.8 x 3.3 μm while others like E. reimeri get as large as 89 x 26.5 μm.

Species Species:

Encyonema abruptirostratum Metzeltin, Kulikovskiy & Lange-Bertalot, 2012 Encyonema accedens Krammer & Lange-Bertalot, 1998 Encyonema acquapurae Wengrat, Marquardt & C.E.Wetzel, 2017 Encyonema acquasede Marquardt, A.C.R.Rocha & C.E.Wetzel, 2016 Encyonema acuminatum Z.X.Shi, 2013 Encyonema aequilongum Lange-Bertalot & Krammer, 1997 Encyonema affine Metzeltin & Krammer, 1997 Encyonema africanum Krammer, 1997 Encyonema alpha Heinzerling, 1908 Encyonema alpiniforme Krammer, 1997 Encyonema alpinum D.G.Mann, 1990 Encyonema altiplanense Lange-Bertalot, 2000 Encyonema amanianum Krammer, 1997 Encyonema amazonianum Vouilloud, S.E.Sala, Núñez-Avellaneda & S.R.Duque, 2010 Encyonema ampliatum Krammer & Lange-Bertalot, 1997 Encyonema andranokelynum Krammer, 1997 Encyonema angustecapitatum Krammer, 1997 Encyonema angustum T.Marsson, 1900 Encyonema ankobraense Krammer, 1997 Encyonema antogaryanum Krammer, 1997 Encyonema apiculatum Krammer, 1997 Encyonema appalachianum M.Potapova, 2014 Encyonema arcus Ralfs, 1861 Encyonema aueri Krammer, 1997 Encyonema auerswaldii Rabenhorst, 1853 Encyonema bacillum Kulikovskiy, Metzeltin & Lange-Bertalot, 2012 Encyonema baicalense Kulikovskiy, Metzeltin & Lange-Bertalot, 2012 Encyonema baicalosilesiacum Kulikovskiy, Metzeltin & Lange-Bertalot, 2012 Encyonema beta Heinzerling, 1908 Encyonema biarcuatum Metzeltin & Lange-Bertalot, 2003 Encyonema bipartitum Krammer, 1997 Encyonema blancheanum Krammer, 1997 Encyonema bonapartei Heudre, Wetzel & Ector, 2016 Encyonema bourrellyi Metzeltin & Lange-Bertalot, 2007 Encyonema braunii D.G.Mann, 1990 Encyonema brehmiforme Krammer, 1997 Encyonema brehmii D.G.Mann, 1990 Encyonema brevicapitatum Krammer, 1997 Encyonema brewerianum Krammer, 1997 Encyonema burovae Kulikovskiy, Metzeltin & Lange-Bertalot, 2012 Encyonema calciphilum Graeff & Kociolek, 2013 Encyonema canadense Krammer & Lange-Bertalot, 1997 Encyonema candangense W.J.da Silva & M.G.Machado de Souza, 2015 Encyonema capixabense Marquardt, Morais & Zorzal-Almeida, 2025 Encyonema carina Lange-Bertalot & Krammer, 1997 Encyonema caronianum Krammer, 1997 Encyonema cascadense Krammer, 1997 Encyonema cespitosum Kützing, 1849 Encyonema chebalingense W.Zhang & S.Blanco, 2021 Encyonema chilense Krammer, 1997 Encyonema costei Metzeltin & Lange-Bertalot, 2007 Encyonema cristatum Frenguelli, 1933 Encyonema cubanense Metzeltin & Lange-Bertalot, 2007 Encyonema dadwinense Krammer, 1997 Encyonema densistriatum E.Novelo, Tavera & C.Ibarra, 2007 Encyonema difficiliformis Krammer, Lange-Bertalot & Metzeltin, 1997 Encyonema difficilis Krammer, 1997 Encyonema directiforme Krammer & Lange-Bertalot, 1997 Encyonema directum K. Krammer, 1997 Encyonema disjunctum Reichardt, 2004 Encyonema distinctepunctatum Krammer, 1997 Encyonema distinctum Lange-Bertalot & Krammer, 1997 Encyonema donatoi Krammer & Lange-Bertalot, 1997 Encyonema drakei Bahls, 2014 Encyonema droseraphilum Bahls, 2013 Encyonema dubium Krammer, 1997 Encyonema elginense D.G.Mann, 1990 Encyonema erdmannense Krammer, 1997 Encyonema evergladianum Krammer, 1997 Encyonema excavatum Z.X.Shi, 2013 Encyonema excisum Frenguelli, 1933 Encyonema exuberans P.I.Tremarin, C.E.Wetzel & T.A. Veiga Ludwig, 2011 Encyonema fogedii Krammer, 1997 Encyonema formosum D.G.Mann, 1990 Encyonema friedelhinzae Krammer, 1997 Encyonema gaeumannii Krammer, 1997 Encyonema geisslerae Krammer, 1997 Encyonema genkalii Lange-Bertalot & Krammer, 2003 Encyonema gerstenbergeri Grunow, 1865 Encyonema gibbum Krammer, 1997 Encyonema girodii Héribaud, 1902 Encyonema globiferum Ralfs, 1861 Encyonema gracile Kirchner, 1879 Encyonema gracile Rabenhorst, 1853 Encyonema gracillimum Metzeltin & Lange-Bertalot, 2007 Encyonema graciloides Krammer, 1997 Encyonema grandi Héribaud, 1903 Encyonema groenlandicum Kulikovskiy & Lange-Bertalot, 2009 Encyonema grossestriatum D.G.Mann, 1990 Encyonema guatemalense Krammer, 1997 Encyonema guettingeri Krammer, 1997 Encyonema hamsherae D.Winter & Bahls, 2013 Encyonema haudelicata Metzeltin & Lange-Bertalot, 2007 Encyonema hebridicum Grunow ex Cleve, 1891 Encyonema hebridiforme Krammer, 1997 Encyonema heilprinense Krammer, 1997 Encyonema hilliardii Krammer, 1997 Encyonema hintzii Krammer, 1997 Encyonema hoelii Krammer, 1997 Encyonema hohnii Krammer, 1997 Encyonema holmenii Krammer, 1997 Encyonema hophense Krammer, 1997 Encyonema horstii Kulikovskiy, Khursevich & Witkowski, 2012 Encyonema hungaricum Krammer, 1997 Encyonema hustedtii Krammer, 1997 Encyonema hyndmanii W.Smith Encyonema inarense Krammer, 1997 Encyonema incertum Krammer, 1997 Encyonema incurvatum Krammer, 1997 Encyonema indistinctum Krammer, 1997 Encyonema inelegans Krammer, 1997 Encyonema insulsum Krammer & Lange-Bertalot, 1998 Encyonema intermedium Héribaud, 1903 Encyonema inuitorum Bahls, 2017 Encyonema javanicum D.G.Mann, 1990 Encyonema jemtlandicum Krammer, 1997 Encyonema jolmolungmense Y.L.Li, 2007 Encyonema jordaniforme Krammer, 1997 Encyonema jordanii F.W.Mills, 1934 Encyonema juriljii D.G.Mann, 1990 Encyonema kabaniense Rodionova & Pomazkina, 2014 Encyonema kalbei Krammer, 1997 Encyonema kamtschaticum Krammer, 1997 Encyonema keshrii S.Roy, C.Radhakrishnan, J.C.Taylor, Kulikovskiy & B.Karthick, 2020 Encyonema khursevichiae Kulikovskiy, Metzeltin & Lange-Bertalot, 2012 Encyonema krasskei Krammer, 1997 Encyonema kuelbsii Lange-Bertalot & Krammer, 1997 Encyonema kukenanum Krammer, 1997 Encyonema kultukense Rodionova & Pomazkina, 2014 Encyonema lacustre Pantocsek, 1901 Encyonema laeve Eichwald, 1852 Encyonema lancettulum Krammer, 1997 Encyonema lange-bertalotii Krammer, 1997 Encyonema lapponicum Krammer, 1997 Encyonema lataerolatum Krammer Encyonema latareolatum Krammer, 1997 Encyonema late-ellipticum Rodionova & Pomazkina, 2014 Encyonema latecapitatum Krammer, 1997 Encyonema latens D.G.Mann, 1990 Encyonema latissimum Krammer, 1997 Encyonema latum Krammer, 1997 Encyonema leei T.Ohtsuka, M.Hanada & Y.Nakamura, 2004 Encyonema leibleinii W.J.Silva, R.Jahn, T.A.V.Ludwig & M.Menezes, 2013 Encyonema lembus Krammer, 1997 Encyonema lineolatum Krammer, 1997 Encyonema lunatum Van Heurck, 1880 Encyonema lunula Grunow, 1875 Encyonema macedonicum Levkov, Metzeltin & Krstic, 2006 Encyonema mackayiana Tempère & M.Peragallo, 1910 Encyonema magnum Krammer, 1997 Encyonema malaysianum Krammer, 1997 Encyonema manguinii Krammer, 1997 Encyonema marginestriatum Krammer & Metzeltin, 1997 Encyonema marvanii Kulikovskiy, Lange-Bertalot, Witkowski & Dorofeyuk, 2009 Encyonema medioasiaticum Metzeltin, Lange-Bertalot & Soninkhishig, 2009 Encyonema meghamalaiense V.Vigheshkumar, A.Vigneshwaran, C.Radhkrishnan, N.Karthick & S.Nagaraj, 2025 Encyonema melidense Krammer, 1997 Encyonema menezesiae W.J.da Silva & M.G.Machado de Souza, 2015 Encyonema menisculus Lange-Bertalot & Krammer, 2003 Encyonema mesianum D.G.Mann, 1990 Encyonema metzeltinii Krammer, 1997 Encyonema mexicanum Krammer, 1997 Encyonema microrobustum Kulikovskiy, Metzeltin & Lange-Bertalot, 2012 Encyonema minusculus Lange-Bertalot & Krammer Encyonema minutiforme Krammer, 1997 Encyonema minutum D.G.Mann, 1990 Encyonema mirabilis Rodionova, Pomazkina & Makarevich, 2013 Encyonema montanum Bahls, 2017 Encyonema moragoense Krammer, 1997 Encyonema morvanense Van de Vijver & Peeters, 2024 Encyonema muelleri D.G.Mann, 1990 Encyonema muscosa Z.X.Shi, 2013 Encyonema natalense Krammer, 1997 Encyonema neocaledonicum Krammer, 1997 Encyonema neogracile Krammer, 1997 Encyonema neomesianum Krammer, 1997 Encyonema neomuelleri Krammer, 1997 Encyonema neosubturgidum Da Silva & Menezes, 2016 Encyonema nevadense S.Blanco, Olenici, De Vicente & F.Guerrero, 2019 Encyonema nicafei Spaulding, 2010 Encyonema nikulinae Kulikovskiy, Metzeltin & Lange-Bertalot, 2012 Encyonema norvegicum Mayer, 1947 Encyonema nylstroomense Krammer, 1997 Encyonema oblogum Q.Liu & S.Xie, 2021 Encyonema obscuriforme Krammer, 1997 Encyonema obscurum D.G.Mann, 1990 Encyonema obtusum Krammer, 1997 Encyonema ochridanum Krammer, 1997 Encyonema octense (R.Maillard ex Lange-Bertalot & G.Moser) Krammer, 1997 Encyonema oestrupii Krammer & Lange-Bertalot, 1997 Encyonema ostrobottnicum Krammer, 1997 Encyonema panamense Lange-Bertalot & Metzeltin, 2009 Encyonema pankowii Lange-Bertalot & Krammer, 1997 Encyonema paradisiacum Marquardt, Wengrat & C.E.Wetzel, 2017 Encyonema paradoxum Kützing, 1834 Encyonema parallelum M.Peragallo, 1909 Encyonema paratropicum Metzeltin & Lange-Bertalot, 2007 Encyonema parvum Krammer, 1997 Encyonema patagonicum Frenguelli, 1942 Encyonema paucistriatum D.G.Mann, 1990 Encyonema pediculus H.Peragallo, 1889 Encyonema pentoniae Bahls, 2014 Encyonema perelginense Krammer, 1997 Encyonema pergracile Krammer, 1997 Encyonema perlangebertalotii Kulikovskiy & Metzeltin, 2012 Encyonema perlucida Rodionova & Pomazkina, 2014 Encyonema perminutum Krammer, 1997 Encyonema perpusillum D.G.Mann, 1990 Encyonema persilesiacum Krammer, 1997 Encyonema picinskae Metzeltin, Witkowski & Krammer, 2003 Encyonema plenum Krammer, 1997 Encyonema polystigmoideum Metzeltin & Krammer, 1998 Encyonema ponspendens Moser, Lange-Bertalot & Metzeltin Encyonema ponteanum Krammer, 1997 Encyonema procerum Krammer, 1997 Encyonema proschkinae Krammer, 1997 Encyonema prostratum Kützing, 1844 Encyonema protractum Eichwald, 1852 Encyonema psammophilum Krammer, 1997 Encyonema pseudocaespitosum Levkov & Krstic, 2007 Encyonema pseudogracile Krammer, 1997 Encyonema pseudoincertum Krammer, 1997 Encyonema pseudolatens Kulikovskiy, Metzeltin & Lange-Bertalot, 2012 Encyonema pseudomuelleri Krammer, 1997 Encyonema pseudoturgidum Pomazkina & Rodionova, 2014 Encyonema ratpanati Llamazares, Bécares & S.Blanco, 2021 Encyonema reflexum Holmboe, 1899 Encyonema reichardtii D.G.Mann, 1990 Encyonema reimeri Spaulding, J.R.Pool & S.I.Castro, 2010 Encyonema rifelanum Krammer, 1997 Encyonema riotecense Krammer, 1997 Encyonema robustum Kulikovskiy, Metzeltin & Lange-Bertalot, 2012 Encyonema rostratum Krammer, 1997 Encyonema rugosiforme Krammer, 1997 Encyonema rugosum D.G.Mann, 1990 Encyonema rumrichiae Krammer, 1997 Encyonema salamonii Metzeltin, 1998 Encyonema sarsii Krammer, 1997 Encyonema schimanskii Krammer, 1997 Encyonema schneideri Krammer, 1997 Encyonema schoemanii Krammer