Fottea X:X | DOI: 10.5507/fot.2026.004

Taxonomic revision of Eunotia indica and infraspecific taxa (Bacillariophyceae) reported by Frenguelli from the Esteros del Iberá (Argentina)

Amelia A. Vouilloud1, 2, José M. Guerrero1, 3, Silvia E. Sala1, 4
1 División Ficología, Museo de La Plata, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, Argentina; e-mail:
2 avouilloud@fcnym.unlp.edu.ar,
3 guerrero@fcnym.unlp.edu.ar,
4 sesala@fcnym.unlp.edu.ar

Eunotia indica, originally described from Banka Island (Indonesia), has been reported worldwide although there is confusion about the identity and actual distribution of this supposedly cosmopolitan species. In 1933 Frenguelli reported 55 different taxa of Eunotia from the Esteros del Iberá (Argentina), a vast wetland with a high rate of endemism. One of the species reported was E. indica together with two new varieties. We examined the original materials contained in the Frenguelli Collection to study the valve morphology of these taxa and elucidate their taxonomic position. For comparison, we also analyzed the original material of E. indica included in the Hustedt Collection. As a result, we conclude that the E. indica complex originally reported from Iberá comprises in fact three different species: Eunotia pseudoindica, Eunotia zygodon and Eunotia hustedtii nov. nom. et stat. nov. whereas Eunotia indica is not present in this wetland. Since Frenguelli did not designate holotypes for the taxa here studied, we designate herein the corresponding lectotypes.

Keywords: diatoms, Frenguelli Collection, lectotypification, new species, South America, taxonomy, valve morphology

Received: November 5, 2025; Revised: April 16, 2026; Accepted: April 28, 2026; Prepublished online: September 9, 2026 

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    References

    1. Bicca, A. B. (2007). A família Eunotiaceae Kutzing (Eunotiales, Bacillariophyta) nas áreas da Lagoa do Casamento e dos Butiazais de Tapes, planície costeira do RS: taxonomia e distribuíção [Master's thesis, Universidade Federal do Rio Grande do Sul]. Lume Repository. https://lume.ufrgs.br/bitstream/handle/10183/12223/000624051.pdf
    2. Bicca, A. B., Torgan, L. C., & Santos, C. D. (2011). Eunotiaceae (Eunotiales, Bacillariophyta) em ambientes lacustres na Planície Costeira do Sul do Brasil. Brazilian Journal of Botany, 34(1), 1-9. https://doi.org/10.1590/S0100-84042011000100002 Go to original source...
    3. Bourrelly, P., & Manguin, E. (1952). Algues d'eau douce de la Guadeloupe et dépendances: recueillies par la Mission P. Allorge en 1936. Société d'Edition d'Enseignement Supérieur.
    4. Boyer, C. S. (1927). Synopsis of North American Diatomaceae. Part I. Coscinodiscatae, Rhizosolenatae, Biddulphiatae, Fragilariatae. Proceedings of the Academy of Natural Sciences of Philadelphia, 78(Suppl.), 1-28.
    5. Bukhtiyarova, L. N. (2019). The genus Eunotia Ehrenb. (Bacillariophyta) in the Cheremsky Nature Reserve, Ukrainian Polissya, and refined terminology relevant to the raphe system morphology. PhytoKeys, 128, 1-31. https://doi.org/10.3897/phytokeys.128.35566 Go to original source...
    6. Burliga, A. L., & Kociolek, J. P. (2012). Four new Eunotia Ehrenberg species (Bacillariophyceae) from pristine regions of Carajás National Forest, Amazonia, Brazil. Nova Hedwigia, 141, 53-70.
    7. Canani, L. G. d. C., Menezes, M., & Torgan, L. C. (2011). Diatomáceas epilíticas de águas oligotróficas e ácidas do Sudeste do Brasil. Acta Botanica Brasi-lica, 25(1), 130-140. https://doi.org/10.1590/S0102-33062011000100016 Go to original source...
    8. Casa, V. (2020). Diatomeas de turberas de Tierra del Fuego: diversidad, ecología y evaluación de su uso como indicadores ambientales [Doctoral dissertation, Universidad de Buenos Aires]. Biblioteca Digital Exactas UBA.
    9. Costa, L. F., Wetzel, C. E., Lange-Bertalot, H., Ector, L., & Bicudo, D. C. (2017). Taxonomy and ecology of Eunotia species (Bacillariophyta) in southeastern Brazilian reservoirs (Bibliotheca Diatomologica, Vol. 64). J. Cramer.
    10. Ehrenberg, C. G. (1837). Über ein aus fossilen Infusorien bestehendes, 1832 zu Brod verbacknes Bergmehl von den Grenzen Lapplands in Schweden. Bericht über die zur Bekanntmachung geeigneten Verhandlungen der Königl. Preuß. Akademie der Wissenschaften zu Berlin, 1, 43-45. Go to original source...
    11. Ehrenberg, C. G. (1843). Verbreitung und Einfluss des mikroskopischen Lebens in Süd- und Nord-Amerika. Abhandlungen der Königlichen Akademie der Wissenschaften zu Berlin, 1841, 291-445.
    12. Frenguelli, J. (1933). Contribuciones al conocimiento de las diatomeas Argentinas. VII. Diatomeas de la región de los Esteros del Yberá (en la Provincia de Corrientes). Anales del Museo Nacional de Historia Natural, 37, 365-475.
    13. Frenguelli, J. (1941). XVI Contribución al conocimiento de las diatomeas argentinas. Diatomeas del Río de la Plata. Revista del Museo de La Plata (Nueva Serie) Botánica, 3, 213-334.
    14. Grunow, A. (1865). Über die von Herrn Gerstenberger in Rabenhorst's Decaden ausgegeben Süsswasser Diatomaceen und Desmidiaceen von der Insel Banka, nebst Untersuchungen über die Gattungen Ceratoneis und Frustulia. In L. Rabenhorst (Ed.), Beiträge zur näheren Kenntniss und Verbreitung der Algen (Heft II). Verlag von Eduard Kummer.
    15. Guerrero, J. M., & Vouilloud, A. A. (2022). Taxonomic revision of E. luna var. aequalis f. paucistriata Frenguelli and Eunotia luna var. aequalis f. major Frenguelli: analysis of type material, lectotyfication and current taxonomic status. Phytotaxa, 561(3), 291-300. https://doi.org/10.11646/phytotaxa.561.3.5 Go to original source...
    16. Guiry, M. D., & Guiry, G. M. (2025). AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org (Accessed 15 October 2025).
    17. Kociolek, J. P., Spaulding, S. A., & Lowe, R. L. (2015). Bacillariophyceae: The Raphid Diatoms. In J. D. Wehr, R. G. Sheath, & J. P. Kociolek (Eds.), Aquatic Ecology, Freshwater Algae of North America (2nd ed., pp. 709-772). Academic Press. https://doi.org/10.1016/B978-0-12-385876-4.00016-5 Go to original source...
    18. Lamaro, A. A., Sala, S. E., Kociolek, J. P., Swenson, J., Simonato, J., Vouilloud, A. A., Guerrero, J. M., & Kociolek, M. (2021). El rol de las nuevas tecnologías en la revalorización de las colecciones biológicas históricas. Un ejemplo: el proyecto "Siguiendo los pasos de Frenguelli en los Esteros del Iberá". Revista del Museo de La Plata, 6(1), 1-13. Go to original source...
    19. Lange-Bertalot, H., B±k, M., & Witkowski, A. (2011). Diatoms of Europe. Diatoms of the European inland water and comparable habitats. Eunotia and some related genera (Vol. 6). A.R.G. Gantner Verlag K.G.
    20. Luchini, L., & Verona, C. A. (1972). Catálogo de las diatomeas Argentinas. I. Diatomeas de aguas continentales (incluido el Sector Antártico) (Monografía 2). Comisión de Investigaciones Científicas de la Provincia de Buenos Aires.
    21. Metzeltin, D., & Lange-Bertalot, H. (1998). Iconographia Diatomologica. Tropical diatoms of South America I: About 700 predominantly rarely known or new taxa representative of the neotropical flora (Vol. 5). Koeltz Scientific Books.
    22. Metzeltin, D., & Lange-Bertalot, H. (2007). Iconographia Diatomologica. Tropical diatoms of South America II. Special remark on biogeographic disjunction (Vol. 18). Koeltz Scientific Books.
    23. Reichardt, E. (1995). Iconographia Diatomologica. Die Diatomeen (Bacillariophyceae) in Ehrenbergs Material von Cayenne, Guyane Gallica (1843) (Vol. 1). Koeltz Scientific Books.
    24. Round, F. E., Crawford, R. M., & Mann, D. G. (1990). The Diatoms. Biology & Morphology of the genera. Cambridge University Press.
    25. Rumrich, U., Lange-Bertalot, H., & Rumrich, M. (2000). Iconographia Diatomologica. Diatoms of the Andes. From Venezuela to Patagonia/ Tierra del Fuego and two additional contributions (Vol. 9: Annotated Diatom Micrographs, Phytogeography-Diversity-Taxonomy). Koeltz Scientific Books.
    26. Sala, S. E., Lamaro, A. A., Duque, S. R., & Núñez-Avellaneda, M. (2002). Diatoms from the Colombian Amazon: some species of the genus Eunotia (Bacillariophyceae). Acta Amazonica, 32(4), 589-603. Go to original source...
    27. Sala, S. E., Vouilloud, A. A., Guerrero, J. M., & Kociolek, P. J. (2023). Taxonomic revision of Eunotia camelus and infraspecific taxa reported by Frenguelli in Esteros del Iberá, Argentina. Nova Hedwigia, 117(1-2), 93-118. Go to original source...
    28. Schmidt, A. (1913). Atlas der Diatomaceen-kunde (Series VII, Heft 73, pls. 289-292). O.R. Reisland. [Materiál zpracoval F. Hustedt].
    29. Simonsen, R. (1987). Atlas and catalogue of the diatom types of Friedrich Hustedt (Vols. 1-3). J. Cramer in der Gebrüder Borntraeger Verlagsbuchhandlung.
    30. Siver, P. A., Hamilton, P. B., & Morales, E. A. (2006). Two new planktic species of Eunotia (Bacillariophyceae) from freshwater waterbodies in North Carolina, U.S.A. Algological Studies, 119, 1-16. https://doi.org/10.1127/1864-1318/2006/0119-0001 Go to original source...
    31. Souza-Mosimann, R. M., Laudares-Silva, R., Talgatti, D., & D'Aquino-Rosa, V. (2011). The diatom flora in Conceição Lagoon, Florianópolis, SC, Brazil. INSULA Revista de Botânica, 40, 25-44. Go to original source...
    32. Swenson, J. (2020). Diatoms of the Esteros del Iberá. A Taxonomic and Ecological Comparison of Historic and Contemporary Collections [Master's thesis, University of Colorado].
    33. Taylor, J. C., Cocquyt, C., & Mayama, S. (2016). New and interesting Eunotia (Bacillariophyta) taxa from the Democratic Republic of the Congo, tropical central Africa. Plant Ecology and Evolution, 149(3), 291-307. Go to original source...
    34. Tremarin, P. I., Ludwig, T. A. V., & Moreira Filho, H. (2008). Eunotia Ehrenberg (Bacillariophyceae) do rio Guaraguaçu, litoral do Paraná, Brasil. Acta Botanica Brasilica, 22(3), 845-862. Go to original source...
    35. VanLandingham, S. L. (1969). Catalogue of the fossil and recent Genera and Species of Diatoms and their Synonyms. Coscinophaena through Fibula (Vol. 3). J. Cramer.
    36. Vouilloud, A. A. (2003). Catálogo de diatomeas continentales y marinas de Argentina. Asociación Argentina de Ficología.
    37. Wetzel, C. E. (2011). Biodiversidade e distribução espacial de diatomáceas (Bacillariophyceae) na bacia hidrográfica do Rio Negro, Amazonas, Brazil [Doctoral dissertation, Instituto de Botânica da Secretaria de Estado do Meio Ambiente].

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