Order Fragilariales

Family Fragilariaceae Greville

Genus Asterionella Hassall

• Asterionella formosa Hassall – freshwater; periphyton (Dressler, 2003).
• Asterionella gracillima (Hantzsch) Heiberg — planktonic, common, lakes
• Asterionella glacialis Castracane — marine, planktonic (Rat'kova, 2000).

Genus Catacombаs D. M. Williams & Round

• Catacombаs gaillonii (Bory de Saint-Vincent) D. M. Williams & Round – marine, littoral; single finding (Бондарчук, 1970: Synedra gaillonii (Bory de Saint-Vincent) Ehrenberg).

Genus Ceratoneis Ehrenberg

• Ceratoneis arcus Kützing – marine, littoral, diluted areas; sporadic (Бондарчук, 1970). Marine, mouth area of the Nilma River; planktonic; dominant (Лихачёва, 2003).
  • C. arcus var. lineari Holmboe – single finding in fouling (Бондарчук, 1970).

Genus Ctenophora (A. Grunow) D. M. Williams & Round

• Ctenophora pulchella (Ralfs ex Kützing) D. M. Williams & Round var. pulchella – marine, littoral; benthic, periphyton; rare, everywhere (Бондарчук, 1970: Synedra pulchella Ralfs ex Kützing; S. pulchella var. lanceolata O'Meara – very rare, together with type variation).

Genus Diatoma Bory de Saint-Vincent

• Diatoma elongatum (Lyngbye) C. Agardh – marine, littoral, mouths of brooks; sporadic (Бондарчук, 1970).
• Diatoma hyemalе (Roth) Heiberg – marine, littoral, mouths of brooks; sporadic (Бондарчук, 1970).
• Diatoma moniliformis (Kützing) D.M.Williams - freshwater, periphyton; in the plankton of meromictic lake Trekhtzvetnoe (Mindolina, 2025).
• Diatoma tenuе C. A. Agardh (=Diatoma tenuis) – freshwater; periphyton (Dressler, 2003); in the plankton of meromictic lake Trekhtzvetnoe (Mindolina, 2025; Ivanova, 2025, personal communication).
• Diatoma vulgare Bory de Saint-Vincent — planktonic,benthic, common, sublittoral, freshwater

Genus Fragilaria Lyngbye

• Fragilaria capucina Desmazières var. capucina – marine, littoral; benthic, periphyton; rare (Бондарчук, 1970). Freshwater; periphyton (Dressler, 2003: F. capucina var. mesolepta Rabenhorst and F. capucina var. vaucheriae (Kützing) Lange-Bertalot).
  • Fragilaria cf. capucina var. gracilis (Østrup) Hudsted – freshwater; periphyton (Dressler, 2003).
• Fragilaria construens (Ehrenberg) Grunow – marine, littoral; often in significantly diluted areas (Бондарчук, 1970). Freshwater, Verkhneye (Upper) Lake, Vodoprovodnoye (Potable water) Lake; planktonic (Бизина, 1998). Freshwater; periphyton (Dressler, 2003: as F. construens (Ehrenberg) Hudsted f. construens and F. construens f. venter (Ehrenberg) Grunow).
• Fragilaria crotonensis Kitton – marine, mouth area of the Nilma River; planktonic; dominant (Лихачёва, 2003). Freshwater; periphyton (Dressler, 2003); in plankton of meromictic lake Trekhtzvetnoe Ivanova, 2025, personal communication).
• Fragilaria hyalina (Kützing) Grunow ex Van Heurck – marine, littoral; benthic, periphyton; in some areas abundant (Бондарчук, 1970).
• Fragilaria islandica Grunow ex Van Heurck – marine; planktonic (Конопля, 1974). Marine; planktonic; dominant (Возжинская, 1975).
• !!!Fragilaria parasitica (W.Smith) Heiberg – currently regarded as a synonym of Pseudostaurosira parasitica (see below).
  • !!!Fragilaria parasitica var. subconstricta Grunow in Van Heurck (F. parasitica is currently regarded as a synonym of Pseudostaurosira parasitica (see below)) – freshwater; periphyton (Dressler, 2003).
• Fragilaria striatula Lyngbye – marine; littoral; in some areas abundant, particularly in fouling of filamentous macrophytes (Бондарчук, 1970).
• Fragilaria tenera (W.Smith) Lange-Bertalot - freshwater; plankt.; in the plankton of meromictic lake Trekhtzvetnoe (Mindolina, 2025).
  • Fragilaria сf. tenera (W.Smith) Lange-Bertalot – freshwater; periphyton (Dressler, 2003); in plankton of meromictic lake Trekhtzvetnoe Ivanova, 2025, personal communication).
• Fragilaria ulna (Nitzsch) Lange-Bertalot – freshwater; periphyton (Dressler, 2003: as F. ulna var. ulna s.l. and F. ulna var. angustissima).

Genus Fragilariforma D. M. Williams & F. E. Round

• Fragilariforma virescens (Ralfs) D.M. Williams & Round – marine; littoral; benthic, periphyton; everywhere; not abundant (Бондарчук, 1970: as Fragilaria virescens Ralfs).

Genus Hannaea R. Patrick in R. Patrick & C. W. Reimer

• Hannaea arcus (Ehrenberg) Patrick — marine, planktonic (Rat'kova, 2000).

Genus Martyana F. E. Round in F. E. Round et al.

• !!!Martyana atomus (Héribaud-Joseph) Round, 1990 (relevant species name Stauroforma atomusmarine, see below) - freshwater. Found in semi-isolated coastal stratified lake Kislo-Sladkoe (Mindolina et al., 2023) and meromictic lake Trekhtzvetnoe (Mindolina, 2025).
• Martyana martyi (Héribaud) F.E. Round – marine, littoral; benthic, periphyton; rare, everywhere (Бондарчук, 1970: as Opephora martyi Héribaud).

Genus Meridion C. Agardh

• Meridion circulare (Greville) C. Agardh – marine, littoral; sporadic in mouths of brooks (Бондарчук, 1970).

Genus Opephora P. Petit

• Opephora marina (Gregory) Petit var. marina – marine, littoral; benthic, periphyton; rare, everywhere (Бондарчук, 1970; O. marina var. minuta – together with type variation, but less often). Marine, littoral; benthic (Сабурова, 1995).
• Opephora mutabilis Sabbe & Wyverman – marine; in the plankton of meromictic lake Trekhtzvetnoe (Mindolina, 2025).

Genus Pseudostaurosira D. M. Williams & F. E. Round

• Pseudostaurosira brevistriata (Grunow) D.M. Williams – marine, littoral; diluted areas; benthic, periphyton; often (Бондарчук, 1970: as Fragilaria brevistriata Grunow). Freshwater; periphyton (Dressler, 2003: F. brevistriata).
• Pseudostaurosira cf. elliptica - freshwater. Found in anaerobic zone of semi-isolated coastal stratified lake Kislo-Sladkoe (Mindolina et al., 2023); in plankt. of meromictic lake Trekhtzvetnoe (Mindolina, 2025).
• Pseudostaurosira parasitica (W.Smith) E.Morales (earlier Fragillaria parasitica, see above) – freshwater; in the plankton of meromictic lake Trekhtzvetnoe (Mindolina, 2025).
• Pseudostaurosira subconstricta (Grunow) Kulikovskiy & Genkal 2011 (earlierFragilaria parasitica var. subconstricta) - freshwater; in the plankton of meromictic lake Trekhtzvetnoe (Ivanova, 2025, personal communication).

Genus Stauroforma Guide

• Stauroforma atomus (old name Martyana atomus, see above) (Hustedt) Talgatti, Wetzel, Morales & Torgan - freshwater. Plankt. in semi-isolated coastal stratified lake Kislo-Sladkoe (Mindolina et al., 2023) and meromictic lake Trekhtzvetnoe (Mindolina, 2025).
• Stauroforma exiguiformis (Lange-Bertalot) Flower, Jones & Round - freshwater.; plankt. in meromictic lake Trekhtzvetnoe (Mindolina, 2025).

Genus Staurosirella D. M. Williams & F. E. Round

• Staurosirella cf. martyi (Héribaud) Morales & Manoylov 2006 - freshwater; in plankton of meromictic lake Trekhtzvetnoe (Mindolina, 2025).
• Staurosirella pinnata (Ehrenberg) D.M. Williams & Round – freshwater; periphyton (Dressler, 2003: as Fragilaria pinnata Ehrenberg var. рinnata). Also found in anaerobic zone of semi-isolated coastal stratified lake Kislo-Sladkoe (Mindolina et al., 2023). In the plankton of meromictic lake Trekhtzvetnoe (Mindolina, 2025).

Genus Synedra Ehrenberg

• Synedra camtschatica Grunow var. camtschatica – marine, littoral, sublittoral; periphyton; often (Бондарчук, 1970: S. kamtschatica Grun.; S. camtschatica var. finnmarchica Cleve & Grunow – together with type variation, less often).
• Synedra crystallina (C. Agardh) Kützing – marine, littoral; rare (Бондарчук, 1970).
• Synedra famelica Kützing – marine, littoral, significantly diluted areas; sporadic (Бондарчук, 1970).
• Synedra fulgens (Greville) W. Smith – marine, littoral, sublittoral; periphyton; rare (Бондарчук, 1970).
• !!!Synedra tabulata (C. Agardh) Kützing (currently regarded as a synonym of Tabularia tabulata (C.Agardh) Snoeijs (see below)).
  • !!!Synedra tabulata (C. Agardh) Kützing var. tabulata – marine, littoral, sublittoral; periphyton; everywhere, dominant (Бондарчук, 1970, 1971, 1980б). Marine; planktonic; spring (Конопля, 1971). Marine; planktonic (Конопля, 1974).
  • S. tabulata var. acuminata Grunow – together with type variation, less often (Бондарчук, 1970).
  • S. tabulata var. affinis Rz. – littoral; rare (Бондарчук, 1970).
  • S. tabulata var. grandis Mereschk. – littoral; in some areas often (Бондарчук, 1970).
  • S. tabulata var. fasciculata (Kützing) Grunow – together with type variation, less often (Бондарчук, 1970).
  • S. tabulata var. obtusa Rant. – together with type variation, rare (Бондарчук, 1970).
  • S. tabulata var. parva (Kützing) Grunow – often, in some areas abundant (Бондарчук, 1970).
• Synedra tenera W. Smith – marine, littoral, significantly diluted areas; rare (Бондарчук, 1970).
• Synedra ulna (Nitzsch) Ehrenberg var. ulna – marine, littoral; rare (Бондарчук, 1970). Marine; mouth area of the Nilma River; planktonic; dominant (Лихачёва, 2003).
  • S. ulna var. aequalis (Kützing) Hustedt – sporadic (Бондарчук, 1970).
  • S. ulna var. danica (Kützing) Grunov – together with type variation; rare (Бондарчук, 1970).

Genus Tabularia (F. T. Kützing) D. M. Williams & F. E. Round

• Tabularia investiens (W. Smith) D. M. Williams & Round – marine, littoral, sublittoral; periphyton; everywhere, not abundant (Бондарчук, 1970: as Synedra investiens W. Smith).
• Tabularia tabulata (C.Agardh) Snoeijs (former species name Synedra tabulata (see above) – marine, freshwater. Also in the plankton of meromictic lake Trekhtzvetnoe (Mindolina, 2025).

Genus Ulnaria F. T. Kützing

• Ulnaria acus (Kützing) M. Aboal – marine, littoral, diluted areas; sporadic (Бондарчук, 1970: as Synedra acus Kützing).

Genus Nanofrustulum F.E. Round, H. Hallsteinsen & E. Paasche

• Nanofrustulum trainorii (E.Morales) E.Morales - freshwater. In semi-isloated coastal stratified lake Kislo-Sladkoe (Mindolina et al., 2023); in plankton of meromictic lake Trakhtzvetnoe (Mindolina, 2025).

Семейство Staurosiraceae Guiry (2024)

Genus Nanofrustulum F.E. Round, H. Hallsteinsen & E. Paasche

• Nanofrustulum trainorii (E.Morales) E.Morales - freshwater. In semi-isloated coastal stratified lake Kislo-Sladkoe (Mindolina et al., 2023); in plankton of coastal meromictic lakes Trakhtzvetnoe (Mindolina, 2025; Ivanova, 2025, personal communication) and Elovoe (Nagaeva, 2025, personal communication).