« It is very similar to R. ventricosa, but may be distinguished by the less slender habitus, by the spiral sculpture which is degenerated into a few weak spiral striae at the base of the shell, and by the pattern of spiral rows of tiny dark spots, which is somewhat more conspicuous than in R. ventricosa, giving the shell a slightly darker appearance. » – A. Verduin: “On the systematics of some Recent Rissoa”, Basteria vol. 50, p.16. – 1m deep, on Zostera, Gelendzhik, Novorossijsk, Krasnodar Krai, NE. Black Sea. 7mm.

Verduin: « There can be little doubt that R. splendida is a good species, different from R. ventricosa. Both are rather constant in their entire range, and both occur together at many localities in the Adriatic Sea, where they do not seem to hybridize.  »– 1m deep, on algae, near Tekirdağ, N. Marmara, NW. Turkey. 4,6mm.