(Lange-Bert. in Lange-Bert. and Krammer) Lange-Bert. 1999
Nupela tenuicephala has more linear valves, with asymmetric valve margins. Nupela wellneri has less capitate apices and raphe slits on both valves.
(Hust.) Lange-Bert. 1993
(Lange-Bert. in Lange-Bert. and Krammer) Lange-Bert. in Rumrich, Lange-Bert. and Rumrich 2000