Chondrina avenacea

Oat grain auger ( Chondrina avenacea )

The oat grain auger ( Chondrina avenacea ), also Western oat grain auger, common oat grain auger or just called grain oats, is a terrestrial snail from the family of the grain auger ( Chondrinidae ). She lives exclusively by endolithic algae, the surface of limestone including those living in algae and lichens is scraped.

Features

The housing is relatively small; it is 6 to 8 mm high and measures 2.3 to 2.5 mm in thickness. It is cylindrical, conical, and has seven to eight turns. The seam is formed clearly, the last whorl occupies about a third of the housing height. The mouth is elliptical, the white aperture rim is only slightly expanded and hardly bent back. The mouth rim is interrupted relatively thin and in the palatal the mouth. The casing is colored dark gray to reddish brown and shows the largely smooth, non- shiny surface a variable striation. It can be coarse to fine, also the distances between the stripes vary greatly. The case is very often covered with stone dust or braiding residues. Inside the mouth is yellowish to reddish brown the housing. In the mouth usually extend eight, strong "teeth" into it; three Palatalzähne, an overlying Suprapalatalzahn ( somewhat weaker formed or absent), and one each from Angular and Parietalzahn and one columellar and Infracolumellarzahn.

Geographic occurrence and habitat

The oat grain auger is widespread in Central Europe, but very scattered and strictly tied to the areas where lime or dolomite is present at the surface. It comes from the Spanish Mediterranean coast (about height Valencia), South and Eastern France, smaller deposits in southern Belgium, in front of about Switzerland, Southern Germany, Austria, northern Italy to the Czech Republic and isolated in Bulgaria. In Germany, the northernmost occurrence is located in Thuringia ( Hörselberge at Eisenach ).

The oat grain auger is strictly bound to lime or dolomite. It settles the sunlit sides of rocks and cliff faces. The animals are active only in high humidity, rainy weather or on wet surfaces. In the dry, they retreat into the housing, but attach the housing through dried mucus firmly to the rock. In this way, they can be deported at the rock excavation. They spend Extreme drought in the detritus and debris under the rocks. In the mountains, it rises to a height of 1800 m above sea level.

Way of life

The oat grain auger feed on endolithic Kalkflechten, algae and detritus. The animals grate using their radula from the outer thin layer of rock, including of their drilling algae and lichens. You do not eat green, higher plants. The animals are fully grown after about three to five years and reach a maximum age of ten.

System

The species is currently divided into six subspecies:

• Chondrina avenacea avenacea ( Bruguiere, 1792)
• Chondrina avenacea istriana Ehrmann, 1931
• Chondrina avenacea latilabris ( Stossich, 1895)
• Chondrina avenacea lepta ( Westerlund, 1887)
• Chondrina avenacea lessinica ( Adami, 1885)
• Chondrina avenacea veneta H. Nordsieck, 1962

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