Gomphonema graciloides, Hustedt, 1965

Gomphonema graciloides was described from mosses at 1000 m in Parque Nacional do Itatiaia, Brazil ( Hustedt 1965: 410, figs 43, 44), is the most similar species and could be easily confused with G. correntinum . However, it is distinguished by its slender valves, less asymmetrical to the apical axis, and its much lower areola density ( 28 in 10 μm).

We found that smaller specimens of G. perapicatum , a species described from Guyana, are similar in outline to G. correntinum while the larger ones are clearly different. Moreover, the former has larger valves (40–75 x 12–13.5 μm), lower stria ( 7–8 in 10 μm) and areola ( 15–18 in 10 μm) densities, and areolae clearly discernible under LM ( Metzeltin & Lange-Bertalot 2007).

We are grateful to Michael D. Guiry and an anonymous reviewer for comments and suggestions that improved our manuscript.

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: 365475.

Frenguelli, J. ( 1953). XIX Contribución al conocimiento de las diatomeas argentinas. Diatomeas del Territorio Nacional de Misiones. Revista del Museo de la Ciudad Eva Perón Nueva Serie 8 ( Botánica No. 32): 63–86, 3 pls.

Guiry, M.D. & Guiry, G.M. 2025. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 01 April 2025.

Herbst, N. & Maidana, N.I. ( 1989). Diatoms of Chaco (República Argentina): 1. Nova Hedwigia 49 (1/ 2): 207–232, incl. I pl., 1 fig. [map].

Hustedt, F. ( 1965). Neue und wenig bekannte diatomeen. IX. Süsswasserdiatomeen aus Brasilien, insbesondere des Amazonasgebietes. Internationale Revue der gesamten Hydrobiologie 50 ( 3): 391–410.

Metzeltin, D. & Lange-Bertalot, H. ( 2007). Tropical diatoms of South America II. Special remarks on biogeography disjunction. Iconographia Diatomologica 18: 1–877, incl. 296 pl.

Radhakrishnan, C., Das, S.K., Kumar, V., Kociolek, J.P. & Karthick, B. ( 2020). A new freshwater Gomphonema Ehrenberg (Bacillariophyta) species from Eastern Himalayas, India. Fottea 20 ( 2): 128–136, 35 fig., 1 table.

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

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Shenzhen , China, July 2017. Regnum Vegetabile, Vol. 159. pp. [i]-xxxviii, 1–253. Glashütten: Koeltz Botanical Books .

Vouilloud, A.A., Guerrero, J.M., & Morales, E.A. (2022). Fragilaria pinnata var. subcapitata Frenguelli , typification and current taxonomic status. Phytotaxa 566(1), 133–139.

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