Cymbella grossestriata var. recta Frenguelli, 1938 accepted as
Navicula norae Metzeltin, Lange-Bertalot & García-Rodríguez, 2005 accepted as
Seminavis norae (Metzeltin, Lange-Bertalot & García-Rodriguez) D.M. Talgatti & L.C. Torgan, 2017 (original description)
Gyrosigma spenceri f. curvula (Ehrenberg) Frenguelli, 1938 accepted as
Navicula curvula Ehrenberg, 1838 (new combination reference)
Hantzschia minima Frenguelli, 1938 (original description)
Mastogloia pumila var. lanceolata Frenguelli, 1938 (original description)
Melosira echinus Frenguelli, 1938 accepted as
Pseudopodosira echinus (Frenguelli) D. Metzeltin, H. Lange-Bertalot & F. García-Rodríguez, 2005 † (original description)
Navicula huei var. ovalis Frenguelli, 1938 (original description)
Navicula humerosa var. ovalis Frenguelli, 1938 (original description)
Navicula oceanica (Karsten) Frenguelli, 1938 accepted as
Navicula directa var. oceanica Karsten, 1905 (new combination reference)
Navicula rara Frenguelli, 1938 (original description)
Navicula subantarctica Frenguelli, 1938 (original description)
Plagiogramma simplex Frenguelli, 1938 accepted as
Desikaneis simplex (Frenguelli) P.Tremarin, L.Procopiak & T. Ludwig in K.K. Serieyssol et al., 2009 (original description)
Synedra affinis var. platensis Frenguelli, 1928 accepted as
Tabularia platensis (Frenguelli) Sar & Sala, 2009 (source of synonymy)
Synedra platensis Frenguelli, 1938 accepted as
Tabularia platensis (Frenguelli) Sar & Sala, 2009 (status source)
Tabularia platensis (Frenguelli) Sar & Sala, 2009 (additional source)
Tryblionella hantzschiana var. maxima (Grunow) Frenguelli, 1938 accepted as
Nitzschia tryblionella f. tryblionella Hantzsch in Rabenhorst, 1860 (new combination reference)
Tryblionella perversa (Grunow) D.G.Mann, 1990 accepted as
Nitzschia perversa Grunow, 1880 (new combination reference)
Tryblionella querandina Frenguelli, 1938 (original description)