Planorbarius grandis

Planorbarius grandis has a large shell with about 4 whorls, or revolutions.The whorls are convex and increase in size rapidly with each successive whorl. The shell opening, called the aperture, is shaped like a kidney.^[1]

(Original description in German) The shell is large and uncommonly ventricose (or bulging), it is quite glossy, and it is finely striated (or grooved) with 4 very inflated whorls, which are separated by a deep suture and are much higher than they are wide. The shell is deeply umbilicate at the top with a hidden protoconch, [and it is] concave below, showing the entire spire right into the center.^[4]

It is very similar in appearance to Planorbarius corneus, and very few differences between the two have been found.^[3]

Planorbarius grandis can be found in Europe, and has been recorded in the basin of the Danube River, as well as around Transylvania, the Black Sea and Baltic Sea.^[3][5] Reports of this species extending into Southern Europe and Western Siberia also exist.^[3] Its distribution may be similar to that of Planorbis corneus.^[4]