Amphipleura lindheimeri var. neotropica Frenguelli, 1933 (original description)
Anomoeoneis sculpta f. gigantea (M. Peragallo in Héribaud) Frenguelli, 1933 accepted as Navicula sculpta f. gigantea M. Peragallo in Héribaud et al., 1920 (new combination reference)
Denticula yberiensis Frenguelli, 1933 (original description)
Diploneis elliptica var. tropica (Zimmermann) Frenguelli, 1933 accepted as Navicula elliptica var. tropica Zimmermann, 1918 (new combination reference)
Diploneis zannii Frenguelli, 1933 (original description)
Encyonema cristatum Frenguelli, 1933 (original description)
Encyonema excisum (M. Peragallo & Héribaud in Héribaud) Frenguelli, 1933 accepted as Encyonema ventricosum var. excisa M. Peragallo & Héribaud in Héribaud, 1893 (new combination reference)
Encyonema excisum f. minor Frenguelli, 1933 (original description)
Eunotia camelus f. major Frenguelli, 1933 (original description)
Eunotia camelus f. minor Frenguelli, 1933 (original description)
Eunotia camelus var. arcuata Frenguelli, 1933 accepted as Eunotia ectorii Sala & Kociolek, 2023 (original description)
Eunotia camelus var. juga Frenguelli, 1933 accepted as Eunotia juga Vouilloud & Kociolek, 2023 (original description)
Eunotia camelus var. undulata Frenguelli, 1933 accepted as Eunotia juga Vouilloud & Kociolek, 2023 (original description)
Eunotia correntina Frenguelli, 1933 (original description)
Eunotia didyma var. jugulata Frenguelli, 1933 (original description)
Eunotia didyma var. papilio Frenguelli, 1933 (original description)
Eunotia didyma var. pileus (Ehrenberg) Frenguelli, 1933 accepted as Eunotia pileus (Ehrenberg) Reichardt (new combination reference)
Eunotia formica f. curta Frenguelli, 1933 (original description)
Eunotia formica f. elongata (Grunow) Frenguelli, 1933 accepted as Eunotia formica var. elongata Grunow, 1865 (new combination reference)
Eunotia indica Frenguelli, 1933 (original description)
Eunotia juga Vouilloud & Kociolek, 2023 (original description)
Eunotia larva Frenguelli, 1933 (original description)
Eunotia luna f. major Frenguelli, 1933 (original description)
Eunotia luna f. paucistriata Frenguelli, 1933 (original description)
Eunotia luna var. major Frenguelli, 1933 (original description)
Eunotia lunaris f. arcuata Frenguelli, 1933 (original description)
Eunotia lunaris f. cuspidata (Schumann) Frenguelli, 1933 accepted as Ceratoneis lunaris var. cuspidata Schumann, 1867 (new combination reference)
Eunotia lunaris f. rigida Frenguelli, 1933 (original description)
Eunotia lunaris f. subarcuata (C.W.Nägeli) J.Frenguelli, 1933 accepted as Synedra subarcuata Naegeli ex Kützing, 1849 (new combination reference)
Eunotia lunaris var. major (Grunow) Frenguelli, 1933 (new combination reference)
Eunotia lunaris var. perlonga Frenguelli, 1933 (original description)
Eunotia pileata Frenguelli, 1933 (original description)
Eunotia producta Frenguelli, 1933 (original description)
Eunotia pseudoindica Frenguelli, 1941 (original description)
Eunotia pseudoindica var. pseudoindica Frenguelli, 1941 accepted as Eunotia pseudoindica Frenguelli, 1941 (original description)
Eunotia silviasalae Guerrero & Vouilloud (original description)
Eunotia sudetica var. undulata Frenguelli, 1933 (original description)
Eunotia yberai Frenguelli, 1933 (original description)
Eunotia yberai var. major Frenguelli, 1933 (original description)
Eunotia zygodon var. major Frenguelli, 1933 (original description)
Eunotia zygodon var. maxima Frenguelli, 1933 (original description)
Fragilaria brevistriata var. obtusa Frenguelli, 1933 (original description)
Gomphonema correntinum Frenguelli, 1933 (original description)
Gomphonema yberiense Frenguelli, 1933 (original description)
Hantzschia elongata var. longissima Frenguelli, 1933 (original description)
Hantzschia exilis Frenguelli accepted as Nitzschia amphioxys var. exilis Frenguelli, 1926 (new combination reference)
Hantzschia limi (Frenguelli) Frenguelli, 1933 accepted as Nitzschia limi var. limi Frenguelli, 1926 (new combination reference)
Melosira italica var. laevis (Ehrenberg) Frenguelli, 1933 accepted as Gaillonella laevis Ehrenberg, 1854 (new combination reference)
Melosira italica var. semilaevis (Grunow in Van Heurck) Frenguelli, 1933 accepted as Melosira semilaevis Grunow in Van Heurck, 1882 (new combination reference)
Navicula craticularis Frenguelli, 1933 (original description)
Navicula fuegiana var. yberiensis Frenguelli, 1933 (original description)
Navicula helea Frenguelli, 1933 (original description)
Navicula multicopsis var. yberai Frenguelli, 1933 (original description)
Neidium affine var. ampliata (Ehrenberg) Frenguelli, 1933 accepted as Navicula ampliata var. ampliata Ehrenberg, 1842 (new combination reference)
Neidium iridis var. amphigomphus (Ehrenberg) Tempère & Peragallo, 1912 accepted as Navicula amphigomphus var. amphigomphus Ehrenberg, 1843 (new combination reference)
Neidium iridis var. dubia (Ehrenberg) Frenguelli, 1933 accepted as Navicula dubia f. dubia Ehrenberg, 1843 (new combination reference)
Nitzschiella lecointei var. correntina Frenguelli, 1933 (original description)
Nitzschiella lecointei var. lecointei (Van Heurck) Frenguelli, 1933 accepted as Nitzschia lecointei van Heurck, 1909 (new combination reference)
Pinnularia acrosphaeria f. minor Frenguelli, 1933 (original description)
Pinnularia acrosphaeria var. americana (Tempère & Peragallo) Frenguelli, 1933 accepted as Navicula acrosphaeria var. americana Tempère & Peragallo, 1913 (new combination reference)
Pinnularia carambolae Frenguelli, 1933 (original description)
Pinnularia clericii var. clericii (Frenguelli) Frenguelli, 1933 accepted as Navicula clericii Frenguelli, 1923 accepted as Pinnularia Clericii (Frenguelli) Mills, 1934 (new combination reference)
Pinnularia clericii var. correntina Frenguelli, 1933 (original description)
Pinnularia correntina Frenguelli, 1933 (original description)
Pinnularia dactylus var. gigas (Ehrenberg) Frenguelli, 1933 (new combination reference)
Pinnularia divergens var. laticeps (Frenguelli) Frenguelli, 1933 accepted as Navicula divergens var. laticeps Frenguelli, 1926 (new combination reference)
Pinnularia divergens var. parallela (Brun) Frenguelli, 1933 † accepted as Pinnularia parallela var. parallela Brun, 1895 (new combination reference)
Pinnularia gibba var. parva (Grunow) Frenguelli, 1933 accepted as Navicula stauroptera var. parva Grunow, 1860 (new combination reference)
Pinnularia gibba var. subundulata (Ant.Mayer) J.Frenguelli, 1933 (new combination reference)
Pinnularia hartleyana var. curta Frenguelli, 1933 (original description)
Pinnularia hemiptera var. obtusa Frenguelli, 1933 (original description)
Pinnularia microstauron f. semicruciata Frenguelli, 1933 (original description)
Pinnularia microstauron var. subproducta (Grunow) Mills accepted as Navicula brebissonii var. subproducta Grunow in Van Heurck, 1880 (new combination reference)
Pinnularia subcapitata var. hybrida (Grunow) J.Frenguelli, 1933 accepted as Navicula bicapitata var. hybrida Grunow, 1880 (new combination reference)
Pinnularia torrendi var. capitata (Zimmermann) Frenguelli, 1933 accepted as Navicula torrendi f. capitata Zimmermann, 1919 (new combination reference)
Pinnularia torrendi var. torrendi (Zimmermann) Frenguelli, 1933 accepted as Navicula torrendi f. torrendi Zimmermann, 1919 (new combination reference)
Pinnularia viridis var. lata (Frenguelli) Frenguelli, 1933 accepted as Navicula viridis var. lata Frenguelli, 1924 (new combination reference)
Stauroneis anceps var. ampliata Frenguelli, 1933 (original description)
Stauroneis correntina Frenguelli, 1933 (original description)
Stauroneis phoenicenteron var. correntina Frenguelli, 1933 (original description)
Stauroneis phoenicenteron var. yberiana Frenguelli, 1933 (original description)
Stauroneis schinzii var. argentina Frenguelli, 1933 emend Guerrero & Vouilloud in Vouilloud et al. 2021 (original description)
Stauroneis schinzii var. maxima Frenguelli, 1933 emend Guerrero & Vouilloud in Vouilloud et al. 2021 (original description)