Achnanthes leonardii Witkowski & Lange-Bertalot, 2000 (original description)
Achnanthes placentuloides (Guslakov) Witkowski & Lange-Bertalot, 2000 accepted as Cocconeis placentuloides Guslakov, 1992 (new combination reference)
Amicula A. Witkowski, H. Lange-Bertalot & D. Metzeltin, 2000 (original description)
Amicula specululum (Witkowski) Witkowski, 2000 accepted as Navicula specululum Witkowski, 1994 (new combination reference)
Amphora jostesorum Witkowski, Lange-Bertalot & Metzeltin, 2000 (original description)
Amphora tomiakae Witkowski, Lange-Bertalot & Metzeltin, 2000 (original description)
Anaulus simonsenii Witkowski, Metzeltin & Lange-Bertalot, 2000 (original description)
Astartiella glacialis Witkowski, Lange-Bertalot & Metzeltin, 2000 (original description)
Astartiella iks Witkowski, Lange-Bertalot & Metzeltin, 2000 (original description)
Astartiella producta Witkowski, Lange-Bertalot & Metzeltin, 2000 (original description)
Austariella A. Witkowski, H. Lange-Bertalot & D. Metzeltin, 2000 (original description)
Austariella admissa (Hustedt) Witkowski, Lange-Bertalot & Metzeltin, 2000 accepted as Navicula admissa Hustedt, 1955 (new combination reference)
Austariella jamalinensis (Cleve) Witkowski, Lange-Bertalot & Metzeltin, 2000 accepted as Navicula jamalinensis var. jamalinensis Cleve in Cleve & Grunow, 1880 (new combination reference)
Austariella jamalinensis var. subcircularis (Østrup) Witkowski, Lange-Bertalot & Metzeltin, 2000 accepted as Navicula jamalinensis var. subcircularis Østrup, 1910 (new combination reference)
Bacillaria paxillifera var. tumidula (Grunow) A. Witkowski, H. Lange-Bertalot & D. Metzeltin, 2000 accepted as Nitzschia paradoxa var. tumidula Grunow, 1880 (new combination reference)
Biremis circumtexta (Meister ex Hustedt) Lange-Bertalot & A.Witkowski, 2000 accepted as Navicula circumtexta F.Meister ex Hustedt, 1934 (new combination reference)
Biremis solitaria (Cleve) Witkowski, Lange-Bertalot & Metzeltin, 2000 accepted as Navicula solitaria Cleve, 1896 (new combination reference)
Brachysira estonarium A. Witkowski, H. Lange-Bertalot & D. Metzeltin, 2000 (original description)
Catenula robusta A. Witkowski, H. Lange-Bertalot & D. Metzeltin, 2000 (original description)
Chamaepinnularia alexandrowiczii A. Witkowski, H. Lange-Bertalot & D. Metzeltin, 2000 (original description)
Chamaepinnularia clamans (Hustedt) Witkowski, Lange-Bertalot & D.Metzeltin, 2000 accepted as Navicula clamans var. clamans Hustedt, 1939 (new combination reference)
Chamaepinnularia distantepunctata (Simonsen, 1974) Witkowski accepted as Navicula distantepunctata Simonsen, 1974 (new combination reference)
Chamaepinnularia justa (Hustedt) Witkowski, Lange-Bertalot & Metzeltin, 2000 accepted as Navicula justa Hustedt, 1955 (new combination reference)
Chamaepinnularia truncata (Dieter König) A.Witkowski, H.Lange-Bertalot & D.Metzeltin, 2000 accepted as Caloneis truncata D.König, 1959 (new combination reference)
Chamaepinnularia wiktoriae (Witkowski & Lange-Bertalot) Witkowski accepted as Navicula wiktoriae A.Witkowski & Lange-Bertalot, 1994 (new combination reference)
Cocconeiopsis A. Witkowski, H. Lange-Bertalot & D. Metzeltin, 2000 (original description)
Cocconeiopsis breviata (Hustedt) Witkowski accepted as Navicula breviata Hustedt, 1966 (new combination reference)
Cocconeiopsis fraudulenta (A. Schmidt in A. Schmidt et al.) A. Witkowski, H. Lange-Bertalot & D. Metzeltin, 2000 accepted as Navicula fraudulenta A.Schmidt, 1881 (new combination reference)
Cocconeiopsis girondica (Dieter König) Witkowski accepted as Navicula girondica Konig, 1959 (new combination reference)
Cocconeiopsis kantsiensis (Giffen) A. Witkowski, H. Lange-Bertalot & D. Metzeltin, 2000 accepted as Navicula kantsiensis Giffen, 1967 (new combination reference)
Cocconeiopsis orthoneoides (Hustedt) Witkowski accepted as Navicula orthoneoides Hustedt, 1955 (new combination reference)
Cocconeiopsis patrickae (Hustedt) A.Witkowski, H.Lange-Bertalot & D.Metzeltin, 2000 accepted as Navicula patrickae Hustedt, 1955 (new combination reference)
Cocconeiopsis pseudorthoneides (Foged) A. Witkowski, H. Lange-Bertalot & D. Metzeltin, 2000 accepted as Navicula pseudorthoneoides Foged, 1975 (new combination reference)
Cocconeiopsis pullus (Hustedt) Witkowski accepted as Navicula pullus Hustedt, 1955 (new combination reference)
Cocconeiopsis regularis (Hustedt) Witkowski accepted as Navicula regularis var. regularis Hustedt, 1955 (new combination reference)
Cocconeiopsis wrightii (O'Meara) Witkowski accepted as Cocconeis wrightii O'Meara, 1867 (new combination reference)
Cocconeis capensis (Cholnoky) A. Witkowski in A. Witkowski, H. Lange-Bertalot & D. Metzeltin, 2000 accepted as Cocconeis clandestina var. capensis Cholnoky, 1963 (new combination reference)
Cocconeis irregularis (Schulz) A. Witkowski in A. Witkowski, H. Lange-Bertalot & D. Metzeltin, 2000 accepted as Cocconeis scutellum var. irregularis Schulz, 1926 (new combination reference)
Cosmioneis eta (Cleve) Witkowski accepted as Navicula eta Cleve, 1893 (new combination reference)
Cymatoneis margarita A. Witkowski in A. Witkowski, H. Lange-Bertalot & D. Metzeltin, 2000 (original description)
Cymbellonitzschia szulczewskii A. Witkowski, H. Lange-Bertalot & D. Metzeltin, 2000 (original description)
Dickieia resistans Witkowski, Lange-Bertalot & Metzeltin, 2000 (original description)
Dickieia wajdae A. Witkowski, H. Lange-Bertalot & D. Metzeltin, 2000 (original description)
Diploneis caffra (Giffen) A. Witkowski, H. Lange-Bertalot & D. Metzeltin, 2000 accepted as Diploneis interrupta var. caffra Giffen, 1970 (new combination reference)
Entomoneis corrugata (Giffen) Witkowski, Lange-Bertalot & Metzeltin, 2000 accepted as Amphiprora corrugata Giffen, 1963 (new combination reference)
Entomoneis kjellmanii var. striolata (Grunow) A.Witkowski, Lange-Bertalot & D.Metzeltin, 2000 accepted as Amphiprora striolata Grunow in Cleve & Grunow, 1880 (new combination reference)
Fallacia balnearis (Grunow) A.Witkowski, H.Lange-Bertalot & D.Metzeltin, 2000 accepted as Navicula pygmaea var. balnearis Grunow, 1880 (new combination reference)
Fallacia cunoniae (Cholnoky) Witkowski, Lange-Bertalot & Metzeltin, 2000 accepted as Navicula cunoniae Cholnoky, 1963 (new combination reference)
Fallacia inscriptura (Hendey) Witkowski, 2000 accepted as Navicula inscriptura Hendey, 1977 (new combination reference)
Fallacia marnieri (Manguin) A. Witkowski, H. Lange-Bertalot & D. Metzeltin, 2000 accepted as Navicula marnieri Manguin, 1957 (new combination reference)
Fallacia melanocephala (Giffen) Witkowski, 2000 accepted as Navicula melanocephala Giffen, 1975 (new combination reference)
Fallacia minima (Østrup) Witkowski accepted as Navicula forcipata var. minima Østrup, 1895 (new combination reference)
Fallacia nicobarica (Grunow) Witkowski accepted as Navicula nicobarica Grunow, 1863 (new combination reference)
Fallacia reichardtii (Grunow) A. Witkowski, H. Lange-Bertalot & D.Metzeltin, 2000 accepted as Navicula reichardtii Grunow, 1880 (new combination reference)
Fallacia schoemaniana (Foged) Witkowski accepted as Navicula schoemaniana Foged, 1975 (new combination reference)
Fallacia spatiata (Østrup) Witkowski accepted as Navicula forcipata var. spatiata Østrup, 1895 (new combination reference)
Fallacia suspirii (Cholnoky) Witkowski accepted as Navicula suspirii Cholnoky, 1961 (new combination reference)
Fogedia acuta (Salah) Witkowski, Lange-Bertalot & Metzeltin, 2000 accepted as Navicula finmarchica var. acuta Salah, 1955 (new combination reference)
Fogedia heterovalvata (R.Simonsen, 2012) Witkowski, Metzeltin & Lange-Bertalot, 2000 accepted as Navicula heterovalvata R.Simonsen, 2012 (new combination reference)
Fragilaria bronkei A. Witkowski, H. Lange-Bertalot & D. Metzeltin, 2000 accepted as Pseudostaurosira bronkei (Witkowski, Lange-Bert. & Metzeltin) C.E.Wetzel & E.Morales, 2019 (original description)
Fragilaria pulchella var. constricta (B.Liebetanz) Witkowski, H.Lange-Bertalot & D.Metzeltin, 2000 (new combination reference)
Fragilaria pulchella var. lanceolata (O'Meara) Witkowski, Lange-Bertalot & Metzeltin, 2000 accepted as Synedra pulchella f. lanceolata O'Meara, 1875 (new combination reference)
Fragilaria quebecensis (Poulin, Hudon & Cardinal) A.Witkowski, H.Lange-Bertalot & D.Metzeltin, 2000 (new combination reference)
Fragilariopsis reginae-jahniae Witkowski, Lange-Bertalot & Metzeltin, 2000 (original description)
Gomphoseptatum pseudoseptatum (Giffen) A. Witkowski, H. Lange-Bertalot & D. Metzeltin, 2000 accepted as Gomphonema pseudoseptatum Giffen, 1970 (new combination reference)
Hantzschia elegantula (Østrup) Witkowski accepted as Hantzschia amphioxys var. elegantula Østrup, 1910 (new combination reference)
Hantzschia kaiseri A. Witkowski, H. Lange-Bertalot & D. Metzeltin, 2000 (original description)
Haslea britannica (Hustedt & Aleem) A. Witkowski, H. Lange-Bertalot & D. Metzeltin, 2000 accepted as Navicula britannica Hustedt & Aleem, 1951 (new combination reference)
Hippodonta caotica A. Witkowski, H. Lange-Bertalot & D. Metzeltin, 2000 (original description)
Hyalinella A. Witkowski, H. Lange-Bertalot & D. Metzeltin, 2000 (original description)
Hyalinella lateripunctata A. Witkowski, H. Lange-Bertalot & D. Metzeltin, 2000 (original description)
Hyalosira delicatula var. gibbosa (Østrup) Witkowski (new combination reference)
Hyalosira parietina A. Witkowski, H. Lange-Bertalot & D. Metzeltin, 2000 (original description)
Kurpiszia A. Witkowski, H. Lange-Bertalot & D. Metzeltin, 2000 (original description)
Kurpiszia kryokonites (Cleve) Witkowski accepted as Navicula kryokonites var. kryokonites Cleve, 1883 (new combination reference)
Kurpiszia semiaperta (Hustedt) A.Witkowski, H-Lange-Bertalot & D.Metzeltin, 2000 accepted as Navicula semiaperta Hustedt, 1936 (new combination reference)
Kurpiszia subprotracta (Cleve) Witkowski accepted as Navicula kryokonites var. subprotracta Cleve, 1883 (new combination reference)
Lunella ghalebii A. Witkowski, H. Lange-Bertalot & D. Metzeltin, 2000 (original description)
Lyrella david-mannii Witkowski, Lange-Bertalot & Metzeltin, 2000 (original description)
Lyrella fogedii A. Witkowski, H. Lange-Bertalot & D. Metzeltin, 2000 (original description)
Lyrella opuntioides (Simonsen) Witkowski accepted as Navicula opuntioides Simonsen, 1959 (new combination reference)
Mastogloia urveae A. Witkowski, H. Lange-Bertalot & D. Metzeltin, 2000 (original description)
Navicula agatkae Witkowski (original description)
Navicula athenae A. Witkowski, H. Lange-Bertalot & D. Metzeltin, 2000 (original description)
Navicula borowkae A. Witkowski, H. Lange-Bertalot & D. Metzeltin, 2000 (original description)
Navicula halinae A. Witkowski, H. Lange-Bertalot & D. Metzeltin, 2000 (original description)
Navicula hamiltonii A. Witkowski, H. Lange-Bertalot & D. Metzeltin, 2000 (original description)
Navicula hanseatica Lange-Bertalot & Stachura, 1998 (original description)
Navicula iserentantii Lange-Bertalot & Witkowski, 2000 † (original description)
Navicula korzeniewskii A. Witkowski, H. Lange-Bertalot & D. Metzeltin, 2000 (original description)
Navicula mahoodii A. Witkowsi & Witton in A. Witkowski, H. Lange-Bertalot & D. Metzeltin, 2000 (original description)
Navicula peregrinopsis H. Lange-Bertalot & A. Witkowski in A. Witkowski, H. Lange-Bertalot & D. Metzeltin, 2000 (original description)
Navicula rajmundii A. Witkowski, H. Lange-Bertalot & D. Metzeltin, 2000 (original description)
Navicula recurva (Meister) A. Witkowski, H. Lange-Bertalot & D. Metzeltin, 2000 accepted as Navicula gracilis var. recurva Meister, 1937 (new combination reference)
Navicula salinarum var. rostrata (Hustedt) Lange-Bertalot, 2000 accepted as Navicula digitoradiata var. rostrata Hustedt, 1939 (new combination reference)
Navicula stachurae A. Witkowski, H. Lange-Bertalot & D. Metzeltin, 2000 (original description)
Navicula streckerae Lange-Bertalot & Witkowski, 2000 (original description)
Navicula vandamii var. mertensiae Lange-Bertalot, 2000 (original description)
Navicula wunsamiae A. Witkowski, H. Lange-Bertalot & D. Metzeltin, 2000 (original description)
Nitzschia plioveterana H. Lange-Bertalot in A. Witkowski, H. Lange-Bertalot & D. Metzeltin, 2000 (original description)