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Superfamily: Ampullarioidea (GRAY 1824)
Family: Viviparidae (GRAY 1847)
Genus: Viviparinae (GRAY 1847)
Species Viviparus (MONTFORT 1810)
Subspecies Viviparus contectus (MILLET 1813)
Description:
The dextrous shell of the pointy river snail grows to (17) 30 to 47 mm in length and (14) 25 to 35 mm in width. The males' shells stay a little smaller and slimmer than those of the females under the same conditions. There are 6 to 6.5 (7) clearly stepped whorls. The apex is pointy, this can be easily felt when touching it with a fingertip. When the apex is worn down or corroded and the whorls are not clearly globose this species can easily be mistaken for the common river snail (Vivparus viviparus) also native in Europe. As a further differentiating characteristic the navel should be inspected more closely: The navel of V. contectus is narrow, too, but clearly more open. When the shell is seen directly from the underside the navel can be seen/is not covered by the aperture lip. The aperture is teardrop-shaped (and thus also the operculum), but it is less pointy than that of Viviparus viviparus.
The shell surface shows a fine structuration by growth lines. ie Oberfläche der Gehäuse ist durch Zuwachslinien fein strukturiert. When growth stops, especially in winter, there is a pronounced "annual ring". The corneus operculum has concentric growth rings which are grouped around the excentric nucleus.
The shell is rather variable in coloring. It is mostly of a greenish-brown to blackish color with three red-brown bands of varying thickness. There are also yellowish (albinotic) or bandless forms, also snails with very broad bands, whose shells thus look nearly black. Greenish stunted forms have been found in waters poor in calcium.In acidic moor tarns nearly black stunted forms with hardly discernable bands have been found.
These snails' broad foot is rounded in a low bow at the front, seamed with a glandular groove, and the back is rounded and a little narrower. The long tentacles are bristle-like, whereas the right tentacle of the male also serves as copulative organ; it is a lot thicker. The eyes are located at the tentacle bases on short stubs. Behind the tentacles, a lobe protrudes on each side. The left one serves to bring fresh water to the gills. On the right lobe the outlet siphon and the food groove are located.
The body and foot are dark brown with orange-yellow or golden yellow dots. There are also partly albinotic snails, whose basic color is an orange pink.
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