Chroodactylon halophilum (Hansgirg) Moshkova ex Levanets & Burova, 2025

Levanets, Anatoliy & Unit, Olga Burova, 2025, Nomenclatural changes in the genus Chroodactylon Hansgirg (Stylonemataceae, Stylonematophyceae), Notulae Algarum 366, pp. 1-5 : 2-5

Chroodactylon halophilum (Hansgirg) Moshkova ex Levanets & Burova , sp. nov.

Basionym: Allogonium halophilum Hansgirg Hedwigia 26(1): 22, no fig., 1887.

Synonym: Asterocytis halophila (Hansgirg) Forti (in De Toni) Sylloge Algarum 5: 691, 1907.

Description. Pseudofilaments are irregularly branched or simple (unbranched), short (up to 90 µm long), uniseriate, attached to substratum. Cells are depressed-spherical, spherical or slightly ellipsoid, cell width 5–11 µm. Cells are connected each other or loosely located, surrounded by mucilaginous transparent sheath which tied near transverse cell walls and adheres more or less tightly to the lateral sides of cells (Figs 2, 3). Olive-yellowish central stellate chloroplast with central, about 3 µm thick, finely grained pyrenoid ( Hansgirg 1887, Moshkova 1970, Moshkova & Frolova 1983).

Lectotype (designated here): [icon!] Hansgirg 1893: fig. 43c (reproduced here as Fig. 2).

Type locality: Bohemia: Aužitz near Kralup [Kralupy nad Vltavou, now in Czechia].

Registration (of species name): http://phycobank.org/105376

Registration (of lectotype): http://phycobank.org/105377

Note: According to Hansgirg (1887) cells are generally 9–10 µm wide, about 6–8 µm long, colourless or encrusted with iron oxide hydrates. Moshkova (1970) noted specimens with cell widths of 8.0–9.7 µm, and Moshkova & Frolova (1983) noted pseudofilaments of 12–18 µm wide, and Hansgirg (1887) also give filament widths of 12–18 µm, but 20 µm wide including the mucilaginous sheaths.

Drouet (1957: 42) in his publication on the herbarium of Anton Hansgirg noted the presence of

Allogonium halophilum type material in the Herbarium of the Naturhistorisches Museum in Vienna

(W) but this material cannot currently be found (Tanja Schuster pers. comm.).

The species was found for the first time outside of Czechia by Moshkova (1970) in the Ukraine (Odesa region, Podilsk [former Troitske] district, Tylihul River near Troitsk Village, epiphytic on shells of the mollusc Limnaea stagnalis L., on 19 May 1954) as Asterocytis halophila Hansgirg. We located Moshkova’s sample – No. 4742(78) - deposited in Algotheca, Herbarium of the M.G. Kholodny Institute of Botany of the National Academy of Sciences of Ukraine (KW) (Fig. 4). Unfortunately, no C. halophilum filaments could be found in the sample. This makes impossible to treat this sample as a type. Moshkova & Frolova (1983: 50) speculated that Chroodactylon halophilum might be a developmental stage of Chroodactylon ramosum (Thwaites) Hansgirg , currently regarded as a synonym of Chroodactylon ornatum . Therefore, this taxon requires an additional detailed examination of the morphology ( Borysova & Sadogurska 2024) as well as comparative DNA sequence data as is needed for all species in the genus ( Vis & Necchi 2021).

Transfer of the following infraspecific taxon name is also required.

Chroodactylon halophilum var. stagnale (Hansgirg) Levanets & Burova , comb. nov.

Basionym: Allogonium halophilum var. stagnale Hansgirg Prodromus der Algenflora von Böhmen 2: 132, no fig. (as ‘var. β stagnale ’), 1893.

Synonym: Asterocytis halophila var. stagnalis (Hansgirg) Forti in De Toni Sylloge Algarum 5: 691, 1907.

Type locality: Bohemia: Čelakowic [now Czech Republic, Čelákovice]; Břeh near Přelouč, on Cladophora spp. and other algae in a freshwater pond on the large Elbe island.

Registration: http://phycobank.org/105378

We are grateful to Dr Tanja Schuster ( Curator of Cryptogams at Natural History Museum Vienna, Vienna, Austria) for her kind help with tracing of Hansgirg’s materials. Michael D. Guiry and the reviewers are gratefully acknowledged for their helpful suggestions .

Basson, P.W. (1979). Marine algae of the Arabian Gulf coast of Saudi Arabia (second half). Botanica Marina 22: 65–82.

Borysova, O.V. & Sadogurska, S.S. (2024). Red algae (Rhodophyta). In: Prodromus of spore plants of Ukraine: algae. Book 1. P.M. Tsarenko (ed.). Kyiv: Naukova Dumka. pp. 711–730 [in Ukrainian: Борисова, О.В., Садогурська, С.С. (2024). Червоні водорості (Rhodophyta). В кн.: Продромус спорових рослин України: водорості. Кн. 1. За ред. П.М. Царенка. Київ: Наукова Думка, c. 711–730].

Burova, O.V., Sadogurska, S.S. & Mikhailyuk T.I. (2024). Chroodactylon ornatum (C.Agardh) Basson (Rhodophyta, Stylonematales) in the flora of Ukraine: distribution, conservation and the data on a new locality. Algologia 34 (4): 294–311, 3 figs. [in Ukrainian: Бурова, О.В., Садогурська, С.С., Михайлюк, Т.І. (2024). Chroodactylon ornatum (C.Agardh) Basson (Rhodophyta, Stylonematales) у флорі України: поширення, охорона та дані про нове місцезнаходження. Альгологія 34 (4): 294–311].

Drew, K.M. & Ross, R. (1965). Some generic names in the Bangiophycidae. Taxon 14: 93-99.

Drouet, F. (1957). Type specimens of algae in the Herbarium of Anton Hansgirg. Annalen des Naturhistorischen Museums in Wien 61: 41–59.

Eloranta, P., Kwandrans, J. & Kusel-Fetzmann, E. (2011). Rhodophyceae and Phaeophyceae. In: Süsswasserflora von Mitteleuropa Band 7. Freshwater flora of Central Europe. Volume 7. Schagerl, M. (ed.), pp. [i]–x, [1]–155. Heidelberg: Spectrum Akademischer Verlag.

Farr, E.R. & Zijlstra, G. [eds]. 2025. Index Nominum Genericorum (Plantarum). 1996 – to date. (http://botany.si.edu/ing/) (accessed 5 March 2025).

Forti, A. (1907). Sylloge algarum omnium hucusque cognitarum. Vol. V. In: De Toni, J.B. Sylloge Algarum Omnium. Sylloge Myxophycearum. pp. i– viii, 1–761. Patavii [Padova]: Sumptibus auctoris.

Ganesan, E.K., West, J.A. & Necchi, O., Jr. (2018). A catalogue and bibliography of non-marine (freshwater and estuarine) Rhodophyta (red algae) of India. Phytotaxa 364 (1): 1–48, 2 figs.

Guiry, M.D. & Guiry, G.M. (2025). AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 15 December 2025.

Hansgirg, A. (1885). Ein Beitrag zur Kenntniss von der Verbreitung der Chromatophoren und Zellkernen bei den Schizophyceen (Phycochromaceen). Berichte der deutsche botanischen Gesellschaft 3: 14–22.

Hansgirg, A. (1887). Über die Gattung Allogonium Ktz. Hedwigia 26 (1): 21–23.

Hansgirg, A. (1893). Prodromus der Algenflora von Böhmen. Zweiter Theil welcher die blaugrünen Algae (Myxophyceen, Cyanophyceen), nebst Nachträgen zum ersten Theile und einer systmatischen Bearbeitung der in Böhmen verbreiten saprophytischen Bacterien und Euglenen enhält. Mit den opiz-preise Gekrönte Arbeit auf Kosten des Opizfondes. Archiv für die naturwissenschaftliche Landesdurchforschung von Böhmen 8 (4): 1–268, 68 figures.

Kant, S. & Gupta, P. (1998). Algal flora of Ladakh. pp. [i–v], [1]–341, 129 pls. Jodhpur: Scientific Publishers (India).

Krishnamurthy, V., Balakrishnan, M.S. & Desikachary, T.V. (1990). Bangiophycidae. In: Rhodophyta. II. Taxonomy part. Part IIA. Desikachary, T.V., Krishnamurthy, V. & Balakrishnan, M.S. (eds), pp. 1–46. Madras, India: Madras Science Foundation.

Moshkova, N.A. (1970). On study of the freshwater red algae of the Ukraine. Ukrainian Botanical Journal 27(5): 563–568 [in Ukrainian: Мошкова Н.O. (1970). До вивчення прісноводних багрянок України. Український ботанічний журнал 27 (5): 563–568].

Moshkova, N.O. & Frolova, I.O. (1983). Red and brown algae (Rhodophyta, Phaeophyta). In: Identification manual of freshwater algae of Ukrainian SSR. Issue 12. Kyiv: Naukova Dumka, 208 pp. [in Ukrainian: Мошкова, Н.О., Фролова, І.О. (1983). Червоні та бурі водорості (Rhodophyta, Phaeophyta). В кн.: Визначник прісноводних водоростей України. Вип. 12. Київ: Наукова думка, 208 с.].

Sheath, R.G. & Vis, M.L. (2015). Red Algae. In: Freshwater algae of North America: ecology and classification. Ed. 2. Pp, 237–264. New York: Academic Press.

Turland, N.J., Wiersema, J.H., Barrie, F.R., Greuter, W., Hawksworth, D.L., Herendeen, P.S., Knapp, S., Kusber, W.-H., Li, D.-Z., Marhold, K., May, T.W., McNeill, J., Monro, A.M., Prado, J., Price, M.J. & Smith, G.F., editors (2018). International Code of Nomenclature for algae, fungi, and plants (Shenzhen Code) adopted by the Nineteenth International Botanical Congress, Shenzhen, China, July 2017. Regnum Vegetabile, Vol. 159. pp. [i]– xxxviii, 1–253. Glashütten: Koeltz Botanical Books.

Vis, M.L. & Necchi, O., Jr. (2021). Freshwater red algae: phylogeny, taxonomy and biogeography. pp. [i]– xii, 1–338. Cham: Springer [Springer Nature Switzerland AG].

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Fig. 1. Chroodactylon filamentosum Ganesan, J.A.West & Necchi ex Levanets ex Levanets & Burova , sp. nov. Holotype: [icon!] from Kant & Gupta 1998: pl. 84: fig. 2.

Fig. 2. Chroodactylon halophilum (Hansgirg) Moshkova ex Levanets & Burova , sp. nov. Lectotype (designated here): [icon!] from Hansgirg 1893: fig. 43c.

Fig. 3. Asterocytis halophila (Hansgirg) Forti (from Moshkova 1970).

Fig. 4. Photo of sample No. 4742(78) deposited in Algotheca, Herbarium of the M.G. Kholodny Institute of Botany of the National Academy of Sciences of Ukraine (KW).