Achnanthes heterovalvata (Krasske) Frenguelli, 1942 accepted as
Achnanthes exigua f. heterovalvata Krasske, 1923 (new combination reference)
Achnanthes heterovalvata var. angustirostrata (Krasske) Frenguelli, 1942 accepted as
Achnanthes exigua f. angustirostrata Krasske, 1939 (new combination reference)
Caloneis subpatagonica Frenguelli, 1942 (original description)
Caloneis subpatagonica f. curta Frenguelli, 1942 (original description)
Cocconeis neuquina Frenguelli, 1942 (original description)
Cyclotella stelligera var. elliptica Frenguelli, 1942 accepted as
Discostella stelligera var. elliptica (Frenguelli) J.M. Guerrero & R.O Echenique, 2006 (original description)
Cyclotella stipata Frenguelli, 1942 accepted as
Guarreraea stipata (Frenguelli) Kociolek & Guerrero in Guerrero et al., 2018 (original description)
Cymbella neuquina Frenguelli, 1942 (original description)
Cymbella rigida Frenguelli, 1942 accepted as
Cymbella helvetica Kützing, 1844 (original description)
Diploneis andina Frenguelli, 1942 accepted as
Muelleria andina (Frenguelli) Guerrero, Vouilloud & Serino 2024 (original description)
Encyonema patagonicum Frenguelli, 1942 (original description)
Encyonema subturgidum Frenguelli, 1942 (original description)
Eunotia andina Frenguelli, 1942 (original description)
Eunotia polydentula var. ventricosa (M. Peragallo) Frenguelli, 1942 accepted as
Eunotia tridentula var. ventricosa M. Peragallo, 1921 (new combination reference)
Fragilaria fonticola f. constricta Frenguelli, 1942 (original description)
Fragilaria fonticola var. subcapitata Frenguelli, 1942 (original description)
Fragilaria fonticola var. tetragona Frenguelli, 1942 (original description)
Gomphonema acuminatum var. spoliata Frenguelli, 1942 (original description)
Gomphonema frickei O.Müller, 1905 (additional source)
Gomphonema frickei Frenguelli, 1923 accepted as
Gomphonema frickei O.Müller, 1905 (source of synonymy)
Gomphonema frickei var. andina Frenguelli, 1942 (original description)
Gomphonema navicelloides Frenguelli, 1942 (original description)
Gomphonema subclavatum var. tenella (Kützing) J.Frenguelli, 1942 accepted as
Gomphonema tenellum var. tenellum Kützing, 1844 (new combination reference)
Hantzschia amphioxys var. inversa Frenguelli, 1942 (original description)
Hantzschia subandina Frenguelli, 1942 accepted as
Nitzschia subandina (Frenguelli) Kociolek & Vouilloud, 2020 (original description)
Navicula andium Frenguelli, 1942 (original description)
Navicula cordillerae Frenguelli, 1942 (original description)
Navicula grimmei var. producta Frenguelli, 1942 (original description)
Navicula grimmii var. producta Frenguelli, 1942 (original description)
Navicula guatemalensis var. minor (Frenguelli) Frenguelli (original description)
Navicula peregrina var. acuta (Mayer) Frenguelli, 1942 (new combination reference)
Navicula pseudocari var. minor Frenguelli, 1942 (original description)
Navicula trolopensis Frenguelli, 1942 (original description)
Neidium affine var. dubia (Ehrenberg) Frenguelli, 1942 accepted as
Navicula dubia f. dubia Ehrenberg, 1843 (new combination reference)
Neidium iridis var. vernalis (Reichelt ex Hustedt) Frenguelli, 1942 (new combination reference)
Neidium kozlowi var. rostrata Frenguelli, 1942 (original description)
Nitzschia denticula var. capitata Frenguelli, 1942 (original description)
Nitzschia sublinearis var. major Frenguelli, 1942 (original description)
Pinnularia alpina var. kerguelensis (Heiden & Kolbe) Frenguelli, 1942 accepted as
Pinnularia kerguelensis H.Heiden (new combination reference)
Pinnularia andina Frenguelli, 1942 (original description)
Pinnularia aperta f. undulata (Frenguelli) Frenguelli, 1942 accepted as
Navicula doeringii var. undulata Frenguelli, 1926 (new combination reference)
Pinnularia aperta var. doellojurandoi (Frenguelli) Frenguelli, 1942 accepted as
Navicula doellojuradoi Frenguelli, 1924 (new combination reference)
Pinnularia aperta var. doeringii (Frenguelli) Frenguelli, 1942 accepted as
Navicula doeringii var. doeringii Frenguelli, 1923 (new combination reference)
Pinnularia appendiculata var. major Frenguelli, 1942 (original description)
Pinnularia bogotensis var. patagonia Frenguelli, 1942 (original description)
Pinnularia cordillerae Frenguelli, 1942 (original description)
Pinnularia crucicula Frenguelli, 1942 (original description)
Pinnularia delicata Frenguelli, 1942 (original description)
Pinnularia delicatula Frenguelli, 1945 accepted as
Pinnularia delicata Frenguelli, 1942 (additional source)
Pinnularia divergens var. subcapitata Frenguelli, 1942 (original description)
Pinnularia elliptica Frenguelli, 1942 accepted as
Pinnularia lamaroana Guerrero & Vouilloud, 2021 (original description)
Pinnularia gracilens Frenguelli, 1942 (original description)
Pinnularia gracilens var. gracilens Frenguelli, 1942 (original description)
Pinnularia graciloides var. krasskei Frenguelli, 1942 accepted as
Pinnularia lange-bertalotii K.Krammer, 1992 (original description)
Pinnularia neuquina Frenguelli, 1942 (original description)
Pinnularia polyonca sensu Frenguelli, 1942 (original description)
Pinnularia streptoraphe var. subacuta Frenguelli, 1942 (original description)
Stauroneis signata Frenguelli, 1942 accepted as
Stauroneis catalanorum Vouilloud, Molinari & Guiry, 2021 (original description)
Surirella linearis f. festetichii (Pantocsek) Frenguelli, 1942 accepted as
Surirella festetichii Pantocsek, 1902 (new combination reference)
Surirella ovata var. elliptica Frenguelli, 1942 (original description)
Tryblionella hantzschiana var. levidensis (W.Smith) Frenguelli, 1942 accepted as
Tryblionella levidensis W.Smith, 1856 (new combination reference)
Tryblionella hungarica (Grunow) Frenguelli, 1942 accepted as
Nitzschia hungarica f. hungarica Grunow, 1862 (new combination reference)
Vanheurckia rhomboides f. marginata (Amossé) Frenguelli, 1942 accepted as
Frustulia marginata Amossé, 1932 (new combination reference)
Vanheurckia rhomboides var. elliptica (Hustedt) Frenguelli, 1942 accepted as
Frustulia rhomboides var. elliptica Hustedt, 1937 (1938) (new combination reference)
Vanheurckia rhomboides var. lanceolata (Zimmermann) Frenguelli, 1942 accepted as
Frustulia lanceolata Zimmermann, 1918 (new combination reference)
Vanheurckia suspecta var. obtusa Frenguelli, 1942 accepted as
Frustulia suspecta var. obtusa (Frenguelli) Woodhead & Tweed, 1960 (original description)
Vanheurckia vulgaris var. capitata (Krasske) Frenguelli, 1942 accepted as
Frustulia vulgaris var. capitata Krasske, 1923 (new combination reference)
Neuquén for
Cyclotella stipata Frenguelli, 1942
Neuquén for
Cyclotella stipata Frenguelli, 1942
Neuquén for
Cymbella rigida Frenguelli, 1942
Neuquén for
Cymbella rigida Frenguelli, 1942
Neuquén for
Diploneis andina Frenguelli, 1942
Neuquén for
Diploneis subovalis var. argentina Frenguelli, 1932
Neuquén for
Encyonema patagonicum Frenguelli, 1942
Neuquén for
Encyonema patagonicum Frenguelli, 1942
Neuquén for
Encyonema subturgidum Frenguelli, 1942
Neuquén for
Eunotia andina Frenguelli, 1942
Neuquén for
Eunotia andina Frenguelli, 1942
Neuquén for
Eunotia andina Frenguelli, 1942
Neuquén for
Fragilaria pinnata var. subcapitata Frenguelli, 1930
Neuquén for
Fragilaria pinnata var. subcapitata Frenguelli, 1930
Neuquén for
Gomphonema frickei var. andina Frenguelli, 1942
Neuquén for
Gomphonema navicelloides Frenguelli, 1942
Neuquén for
Hantzschia amphioxys var. inversa Frenguelli, 1942
Neuquén for
Hantzschia subandina Frenguelli, 1942
Neuquén for
Hantzschia subandina Frenguelli, 1942
Neuquén for
Navicula andium Frenguelli, 1942
Neuquén for
Navicula cordillerae Frenguelli, 1942
Neuquén for
Navicula grimmei var. producta Frenguelli, 1942
Neuquén for
Navicula pseudocari var. minor Frenguelli, 1942
Neuquén for
Navicula pseudocari var. minor Frenguelli, 1942
Neuquén for
Navicula trolopensis Frenguelli, 1942
Neuquén for
Nitzschia sublinearis var. major Frenguelli, 1942
Neuquén for
Nitzschia sublinearis var. major Frenguelli, 1942
Neuquén for
Pinnularia andina Frenguelli, 1942
Neuquén for
Pinnularia cordillerae Frenguelli, 1942
Neuquén for
Pinnularia crucicula Frenguelli, 1942
Neuquén for
Pinnularia crucicula Frenguelli, 1942
Neuquén for
Pinnularia delicata Frenguelli, 1942
Neuquén for
Pinnularia divergens var. subcapitata Frenguelli, 1942
Neuquén for
Pinnularia elliptica Frenguelli, 1942
Neuquén for
Pinnularia neuquina Frenguelli, 1942
Neuquén for
Pinnularia neuquina Frenguelli, 1942
Neuquén for
Pinnularia neuquina Frenguelli, 1942
Neuquén for
Pinnularia neuquina Frenguelli, 1942
Neuquén for
Pinnularia streptoraphe var. subacuta Frenguelli, 1942
Neuquén for
Stauroneis signata Frenguelli, 1942
Neuquén for
Stauroneis signata Frenguelli, 1942
Neuquén for
Surirella ovata var. elliptica Frenguelli, 1942
Neuquén for
Vanheurckia suspecta var. obtusa Frenguelli, 1942
Neuquén for
Vanheurckia suspecta var. obtusa Frenguelli, 1942
Rio Negro for
Cocconeis neuquina Frenguelli, 1942
Rio Negro for
Cymbella neuquina Frenguelli, 1942
Rio Negro for
Fragilaria fonticola var. tetragona Frenguelli, 1942
Rio Negro for
Fragilaria pinnata var. subcapitata Frenguelli, 1930
Rio Negro for
Gomphonema acuminatum var. spoliata Frenguelli, 1942
Rio Negro for
Neidium kozlowi var. rostrata Frenguelli, 1942
Rio Negro for
Nitzschia denticula var. capitata Frenguelli, 1942
Rio Negro for
Pinnularia appendiculata var. major Frenguelli, 1942
Rio Negro for
Pinnularia gracilens Frenguelli, 1942
Rio Negro for
Pinnularia graciloides var. krasskei Frenguelli, 1942