Helicid Snails III: Mediterranean Helicidae
Copse snail (Arianta arbustorum).
Picture: © Alexander Mrkvicka, Vienna (mrkvicka.at).
Family: Helicidae Rafinesque 1815
Source: Mollbase on http://www.mollbase.de/list/.
Explanation of shell characters as means of identification.
Helicid snails (Helicidae) are the the Roman Snail's (Helix pomatia) nearest relatives. This family's members usually have got a spherical shell, that may be flattened. Only in few cases the shell has got apertural teeth. Helicid snails produce a love dart, that is put into action during the (usually mutual) courtship, before copulation (See: Reproduction of Helix pomatia).
Pacific sideband snail (Monadenia fidelis, Monadeniidae), an
American relative of Helicid snails (Source).
The natural area of distribution today spreads over the whole western Palaearctic (see: Faunal provinces), but it is assumed, that the Helicidae snail family originated from Southern Europe and the Mediterranean.
The Helicidae family is divided into several subfamilies: The Ariantinae subfamily with the copse snail (Arianta arbustorum) and its relatives. Another subfamily is the Helicinae with the Roman snail (Helix pomatia) and its relatives. Additionally to Helix itself there are several other edible snail species in the Helicinae, some of which, too, are of economical importance (see: Snail cultivation).
Roman snail (Helix pomatia)
Brown garden snail (Cornu aspersum)
Originally, there are no native Helicidae on the American continents. Those found there have been introduced by man in history, which is why species like Helix pomatia, Cornu aspersum, Theba pisana, Cepaea nemoralis and others do appear in the United States. There are, though, numerous families native to America from the Helicoidea superfamily, among those Helminthoglyptidae, Monadeniidae, Pleurodontidae and Polygyridae.
Hartmut Nordsieck: "Higher classification of Helicoidea (Gastropoda: Stylommatophora) and the molecular analyses of their phylogeny", Part 1: Classification. (Accessed 03.12.2010).
In contrary to other Helicidae snails the juveniles of the Ariantinae subfamily may have hairy shells. The love dart does not possess a crown and has got a two-edge, lancet-shaped blade (see also: Koene, J. M. 2005).
Copse snail - Arianta arbustorum (Linnaeus 1758).
Copse snail (Arianta arbustorum). [RN]
Picture: Helmut Nisters.
Description: The copse snail has got a spherical shell with a conical spire. The shell usually is chestnut brown in colour with straw yellow spots and a dark band. The umbilicus is usually completely concealed by the columellar part of the distinct white apertural lip.
Arianta arbustorum is one of the most variable snail species: There are numerous geographical races, valley and mountain forms. Similarly to the banded snails, selection by snail eating thrushes may also cause an additional variety in copse snail shells depending on ground type and vegetation cover.
During copulation a special stimulation organ is extended from the genital atrium.
Dimensions: W: 14 - 28 mm; H: 10 - 22 mm; N: 5 - 6. (Abbreviations).
Alpine copse snail (Arianta arbustorum alpicola).
Picture: © Alexander Mrkvicka, Vienna (mrkvicka.at).
Habitat and Distribution: In spite of its name the copse snail occurs in open country as well as in forests (copses), preferring humid habitats. In the mountains it will climb until 2700 m above sea level.
The species is distributed over Northwest and Central Europe, including the Alps and the Carpathians. From the Spanish Eastern Pyrenees it occurs until Norway and Iceland. In Ireland it only occurs in the North, in the Eastern Baltic Sea Region only near the coast. In a dispersed pattern the copse snail can be found in the East as far as the Western Ukraine.
Variations of the Copse Snail (Arianta arbustorum).
Alpine Copse Snail - Arianta arbustorum alpicola (A. FÉRUSSAC 1821)
In the Alps a subspecies of the copse snail is found, which is different from the "basic" form in being more strongly ribbed and usually having a lighter colour, so the dark stripe becomes better visible.
Dimensions: H: 12 - 13 mm; W: 16 - 18 mm. (Abbreviations).
Habitat and Distribution: The Alpine copse snail expectedly inhabits high altitude places, but also is found in the valleys, on meadows and near the roadside. If glacial moraines are present, Alpine copse snails can also be found at the foot of the Alps. This points towards this subspecies evolving during the ice ages. The subspecies is distributed all over the Alps, but it is not exclusively a high mountain form, but as well a meadow and grass form, also found in loess. Straw yellow and strong walled forms appear on limestone ground (for example also in the valleys of the Swabian Alb). On swampy ground of the Alpine foot hills there are brown thin-walled forms. On Alpine pastures there are the smallest forms of Arianta arbustorum alpicola, up to 10 mm shell height, such as for example in the Sertig valley in Grisons (Switzerland).
Arianta stenzii. Picture: © Alexander Mrkvicka, Vienna.
Arianta stenzii (Rossmässler 1835)
In southern Austria there is a further relative of the copse snail, of which science is not certain, whether it is to be taken as an own species or a subspecies of Arianta arbustorum. The shell of Arianta stenzii resembles that of Arianta arbustorum, but it has thinner walls and is a bit more depressed. The shell surface shows distinct transverse ribs. Yellow spots of the shell surface sometime melt to form bands, but a distinct longitudinal band lacks in Arianta stenzii. The navel (umbilicus) is open. The snail's body is yellowish or reddish brown.
Lapidary snail (Helicigona lapicida). [RN]
Dimensions: H: 13 - 18 mm; W: 21 - 29 mm. (Abbreviations).
Francisco Welter-Schultes: Arianta stenzii species homepage.
Lapidary Snail - Helicigona lapicida (Linnaeus 1758)
Description: The lapidary snail has got a characteristically lens-shaped shell with a clearly visible keel. The shell has a grey-brown colour with blurred red-brown spots. Because of the shell form the aperture is very oblique, the lip is distinct and whitish. It is set off the shell surface. The umbilicus is wide and open.
The characteristic form of its shell enables the lapidary snail to withdraw into crevices in rock or bark during dryness.
Lapidary snail in Grisons, Switzerland. Not the different colou_
ring! Picture: © Roland Bodenmann.
Dimensions: W: 12 - 20 mm; H: 7 - 9mm; N: 5˝. (Abbreviations).
Habitat and Distribution: Shady rocks and walls (especially those overgrown with ivy) and tree trunks, especially beech, hornbeam and sycamore. Lapidary snails are to be found mainly in hill country and mountainous forests in Western and Central Europe.
They occur from Central Portugal to Central Scandinavia, in Britain up to Southern Scotland. In Southern Ireland the species only occurs as a relict from the warm postglacial. In the Alps the species only occurs north of the main ridge, in the East it is spread as far as the Polish Jura and the Western Carpathians.
Mask Snail - Isognomostoma isognomostomos (Schröter 1784)
Behind the snail species with probably the longest name of the native snail fauna, an striking snail hides, which on the first glance would not appear to be related to copse snails and lapidary snails.
More about the masked snail.
Illyrian Rock Snail - Chilostoma (Faustina) illyrica (Stabile 1864)
Illyrian rock snail (Chilostoma illyrica).
Picture: © Alexander Mrkvicka, Vienna.
Description: The Illyrian rock snail is a medium size snail with a thick disc shaped shell, the spire of which is coiled flatly. The thin-walled shell is horn brown and quite shiny with dissolving stripes. Similar to Aegopis verticillus, on an Illyrian rock snail's shell brighter fields also show growth pauses during hibernation and aestivation. Additionally, Chilostoma illyrica's shell shows a red brown longitudinal band bordered by whitish zones. There also are three-banded forms. The apertural whorl is double as wide as the previous one. The aperture is slightly oblique. The aperture rim shows a distinctive white lip. The shell's navel (umbilicus) is not very wide.
Size H: 13 mm; W: 26 mm; N: 5 - 5˝. (Abbreviations).
Habitat and Distribution: The Illyrian rock snail lives on humid shady limestone rocks, where it is also often found under vegetation and rock rubble. The species' distribution area stretches over the eastern Alps south of the main ridge as far as the Etsch river, to southern Austria, as well as to southern Slovenia. Around 1850 the species was introduced at the Burgberg mountain near Donaustauf in the vicinity of Regensburg.
Illyria (Greek: Ἰλλυρίς Illyris, lat. Illyricum) is an ancient name for the region in the west of the Balkan peninsula.
Francisco Welter-Schultes: Helicigona illyrica species homepage.
Anderson, R. (2008): "An annotated list of the non-marine Mollusca of Britain and Ireland" (PDF).
Koene, J. M. (2005): "Love darts of land snails". Invertebrate Biology 124: 1 (PDF).
Part 2: Subfamily Helicinae.
Part 3: Mediterranean Helicidae.