Cipangopaludina nagaensis (Preston, 1914) new combination (Figs 2O, 3O, 6O) Vivipara nagaensis Preston, 1914: 20 (Naga Hills, India). Remarks: Vivipara nagaensis Preston, 1914 has been rarely mentioned in the literature after its description. Here, it is classified as a species of Cipangopaludina based on its shell morphology and the fact that it exhibits the generic characters of the Cipangopaludina operculum (i.e. as seen in the type species of the genus, C. chinensis). The shell and operculum of C. nagaensis are much smaller than those in C. chinensis and only a small part of the nuclear region in C. nagaensis is covered by the sandpaper-like layer.

Published as part of Zhang, Le-Jia & von Rintelen, Thomas, 2021, The neglected operculum: a revision of the opercular characters in river snails (Caenogastropoda: Viviparidae), pp. 1-14 in Journal of Molluscan Studies (eyab 008) (eyab 008) 87 (2) on pages 9-10, DOI: 10.1093/mollus/eyab008, http://zenodo.org/record/15098489