Achnanthes danicoides Giffen, 1975 (original description)
Amphora langebaanae Giffen, 1975 (original description)
Auliscus sculptus var. rhipis (A. Schmidt) Giffen, 1975 accepted as
Auliscus rhipis var. rhipis Schmidt in Schmidt et al., 1875 (new combination reference)
Auliscus sculptus var. strigillatus (A. Schmidt) Giffen, 1975 accepted as
Auliscus caelatus var. strigillata Schmidt in Schmidt et al., 1875 (new combination reference)
Campylosira inane Giffen, 1975 (original description)
Cocconeis deperdita Giffen, 1975 (original description)
Cymatosira capensis Giffen, 1975 (original description)
Grammatophora lepida Giffen, 1975 (original description)
Navicula infirmitata Giffen, 1975 accepted as
Olifantiella infirmitata (Giffen) Witkowski & Snoeijs in Kaleli et al., 2018 (original description)
Navicula lusoria Giffen, 1975 (original description)
Navicula melanocephala Giffen, 1975 (original description)
Navicula occasa Giffen, 1975 (original description)
Navicula pseudoinflata Giffen, 1975 (original description)
Navicula pseudosalinarum Giffen, 1975 (original description)
Navicula viminoides Giffen, 1975 (original description)
Nitzschia rorida M.H.Giffen, 1975 (original description)
Plagiogramma appendiculatum Griffen, 1975 (original description)
Plagiogramma occasum Giffen, 1975 (original description)