Rotund Disc (Discus rotundatus (O. F. Müller, 1774))

Scientific name: Discus rotundatus (O. F. Müller, 1774)
Common name: Rotund Disc
French name: Bouton commun
Order: Stylommatophora
Size: 5.7 to 7 mm in diameter, 2.4 to 6 mm in height.
Habitat : Forests and dark and damp places, under stones, wood logs and in the litter.
Food: Plant debris, algae and fungi.
Reproduction : Hermaphrodite. The reproduction season lasts from May to October. 20 to 50 eggs are laid in rotting wood or under dead leaves.
Geographic area: Western Europe and Central Europe, from Italy to south of Scandinavia. Introduced to the United States and to Canada.

Snails of the Patulidae family a small size snails with a disc-shaped shell. There are 3 species in this family in Europe.
The umbilicus is broad and shallow. The shell is dull and shows well marked ribs very close to each other.
You can tell Discus rotundatus with reddish brown spots crossing the whorls at regular intervals.
The body is bluish black on the upper side and greyish white on the under side.


Rotund Disc (Discus rotundatus) - Yvelines, France - May 1st 2012
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Rotund Disc (Discus rotundatus)
I have found this Rotund Disc on the ground, under the litter.
The reddish brown spots crossing the whorls at regular intervals are quite visible on this picture.



Rotund Disc (Discus rotundatus) - Yvelines, France - September 22nd 2013
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Rotund Disc (Discus rotundatus)
This other Rotund Disc was found on a piece of rotting wood where it was sitting with other specimens of the same species.



Rotund Disc (Discus rotundatus) - Yvelines, France - May 1st 2012
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Rotund Disc (Discus rotundatus)
I have photographed this shell on graph paper in order to measure its size. The diameter is here 6.5 mm.



Rotund Disc (Discus rotundatus) - Yvelines, France - May 1st 2012
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Rotund Disc (Discus rotundatus)
The under side shows a broad umbilicus.



Rotund Disc (Discus rotundatus) - Yvelines, France - May 1st 2012
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Rotund Disc (Discus rotundatus)
Here is a last view showing the low height of the shell which is the origin of the common name "Disc".

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