Stone picker (snail)

Stone picker
	Stone picker ( Helicigona lapicida )
Systematics
Order :	Lung snails (pulmonata)
Subordination :	Land snails (Stylommatophora)
Superfamily :	Helicoidea
Family :	Schnirkelschnecken (Helicidae)
Genre :	Helicigona
Type :	Stone picker
Scientific name
	Helicigona lapicida
	( Linnaeus , 1758)

The stone pecker ( Helicigona lapicida ) is a species of the snail (Helicidae), which is characterized by a flat, lenticular and characteristic keeled shell, which enables it to retreat into cracks in trees and crevices when it is dry.

features

Helicigona lapicida andorrica

The shell of the stone pecker ( Helicigona lapicida ) differs significantly in its shape from the spherical shell of other Schnirkelschnecken (Helicidae). It is lenticular with a low thread. The outermost turn has a clearly marked edge (keel). The case surface is finely striped and quite roughly grained. If the base color is gray-brown, there are blurred red-brown spots. Albinotic cases are almost transparent. The edge of the mouth is peeled off and expanded into a strong white lip. The navel is wide and open, clearly visible. The case is 12 to 20 millimeters wide, 7 to 9 millimeters high and has around 5½ whorls.

habitat

Stone picker ( Helicigona lapicida ), well camouflaged on tree bark

Stone picker ( Helicigona lapicida ) in a stone crevice

The Steinpicker lives in shady rocks and walls that are often overgrown by vegetation . Despite its name, the snail can be found not only on rocks, but also on trees, mainly deciduous trees such as beech , hornbeam and sycamore maple . In rainy weather they crawl up the trunk to eat the algae that grow on the bark.

The characteristic shape of the Steinpicker housing can be explained as an adaptation to the persistence of dry periods: The lens-shaped flat housing enables the Steinpicker to withdraw into cracks in the bark and cracks in the rock.

distribution

Stone pickers occur mainly in the hill country and in mountain forests of Western and Central Europe . Their distribution area extends from central Portugal to central Scandinavia . In Great Britain the species can be found as far as southern Scotland . In southern Ireland the stone picker, where it appeared as a relic of the post-glacial warm period ( Atlantic Ocean ), was last recorded in 1968 and is believed to be extinct due to habitat loss. In the Alps , with the exception of the Tauferer Ahrntal , it is only widespread north of the main ridge, in the east as far as the Polish Jura and the western Carpathians .

Stone picker's love arrow

literature

Rosina Fechter and Gerhard Falkner: molluscs. Mosaik-Verlag, Munich 1990 (Steinbach's Nature Guide 10), 287 pages ISBN 3-570-03414-3
MP Kerney, RAD Cameron, JH Jungbluth: The land snails of Northern and Central Europe . Parey-Verlag, Hamburg and Berlin 1983, 384 pp. ISBN 3-490-17918-8
Vollrath Wiese: Germany's land snails . Quelle & Meyer Verlag 2014, 352 pp. ISBN 978-3-494-01551-4
D. Geyer: Our land and freshwater mollusks . G. Lutz 'Verlag, Stuttgart 1927 (3rd edition), 262 pp.