Operculate Forest Snails

Cochlostomatidae Kobelt, 1902
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Introduction

 
Cochlostoma septemspirale from Switzerland.
Photo: © Stefan Haller, (schneckenfoto.ch).

Obscurella obscura:  Ariège, Midi-Pyrénées, France.
Photo: Gaëtan Jouvenez (iNaturalist).		  
Similar to the operculate land snails (Pomatiidae), the operculate forest snails (Cochlostomatidae), are terrestrial snails as well, which, opposite to most species of snails, possess a shell lid (operculum) and are more closely related to water-living groups than other terrestrial snails. On the other hand, however, neither are operculate forest snails significantly closely related to operculate land snails. Among their relatives actually rather are the apple snails (Ampullarioidea), as well as the freshwater-living mud snails (Viviparidae).

This makes it probable that the ancestors of those snails have settled dry land over freshwater bodies, not directly from the sea. The ancestors of operculate land snails on the other hand, the closest relatives of which still are the periwinkles (Littorinidae), living in the sea. In the same way probably relatives of the coast snails (Ellobioidea) did, among whose terrestrial relatives are the terrestrial thorn snails (Carychiidae).

How Did Snails Come to Live on Land?

Operculate forest snails have a highly coiled, acute shell with more or less rounded whorls, a characteristically circular shell mouth (aperture) and a wide apertural rim. The shell surface displays pronounced ribs, whose form and density can be taken into account for identification purposes in the same way as in door snails (Clausiliidae). Operculate forest snails have separate sexes, contrary to being hermaphrodites, and so do the operculate land snails.

Systematics

Gastropoda
Subclass: Orthogastropoda
Superorder: Caenogastropoda
Order: Architaenioglossa
Superfamily: Cyclophoroidea
Family: Cochlostomatidae Kobelt, 1902

Source: MolluscaBase eds. (2025): Cochlostomatidae Kobelt, 1902.

Taxonomy of Gastropoda:Clade Caenogastropoda: Cochlostomatidae.

Links

Literature

The Operculate Forest Snails (Cochlostomatidae) of Austria

Source: Wolfgang Fischer et al.: Checklist of Austrian Mollusca.

Lesser Operculate Forest Snail - Cochlostoma septemspirale (Razoumowsky, 1789)


Lesser Operculate Forest Snail (Cochlostoma septemspirale),
from the Salzkammergut in Austria. Photo: Martina Eleveld.		  
   

Cochlostoma septemspirale: Ardèche, Rhône-Alpes, France.
Photo: Maëlan Adam (iNaturalist).		  
Description: The Lesser Operculate Forest Snail has a grey, whitish grey or even reddish brown shell with three rows of more or less pronounced dark spots arranged spirally. The navel (umbilicus) is very narrow and needle-shaped; it is partly concealed by the folded-back apertural rim. The shell surface is strongly ribbed with a rib density of between six and eight ribs per millimetre. There are also transversal ribs in a density of about six per millimetre. The shell aperture is white on the inside. The shell lid (operculum) is horn-like and flexible.

The snail's soft body is of a dark grey to black colour; the foot is undivided. The animals have separate sexes (see above), a slight sexual dimorphism is apparent: The females' shells are slightly more slender, but larger. The females' aperture is slightly reduced in height. The shell volume is about one fifth larger than in a male shell. The ultimate whorl is slightly less pigmented than in males, also the average rib density is higher in female shells.

All characters are strongly ambiguous and taken separately, no character is sufficient to clearly tell apart female and male shells by shell characters alone. In an analytical experiment, where five characters were used, however, 90% of all shells were able to be clearly identified as male or female.

 
Cochlostoma septemspirale from Switzerland.
Photo: © Stefan Haller, (schneckenfoto.ch).
   
 
Cochlostoma septemspirale with two door snails (Clausiliidae):
Isère, Rhône-Alpes, France.
Photo: Guillaume Hoffmann (iNaturalist).
Reichenbach, F.; Baur, H.; Neubert, E. (2012): Sexual dimorphism in shells of Cochlostoma septemspirale. In: Zookeys (208), S. 1–16. (Link).

In the fossil history, Cochlostomatidae are known since the Palaeocene.

Photo of Cochlostoma septemspirale by Stefan Haller.

Dimensions: H: 6.7 - 10.2 mm; W: 3.2 - 4.4 mm; N: 7 - 10. Information: Abbreviations

Habitat and Distribution: The Lesser Operculate Forest Snail lives on rocks and trees on calcareous grounds. The snail is a slow crawler, very shy and usually only active during humid weather. During times of dryness, it closes the operculum. During humid weather, the Lesser Operculate Forest Snail can crawl up trees to about 2 m. Cochlostoma septemspirale feeds on the remains of plants and grazes algae off stones and tree bark.

The distribution area of this species stretches from the Pyrenees over Southern Europe and Southern Germany as far as the middle Balkans. In the mountains, the Lesser Operculate Forest Snail is found in altitudes of up to 2100 m MSL. In Germany, Cochlostoma septemspirale is found in the Upper Rhone area, near Kelheim at the River Danube and near the lower Altmühl river.

Threat Situation: In the German Red List (2012), the Lesser Operculate Forest Snail is listed as extremely rare ( see IUCN Threat Categories).

Subspecies:

In the species Cochlostoma septemspirale several subspecies are distinguished:

Links

Grey Operculate Forest Snail - Cochlostoma henricae (Strobel, 1851)


Grey Operculate Forest Snail (Cochlostoma
henricae): Trentino, South Tyrol.
Photo: Gaëtan Jouvenez (iNaturalist).		  
Description: The dextral shell of the Grey Operculate Forest Snail has a slender elongated form and slowly growing, weakly rounded whorls. The first whorls are evenly covered in pronounced ribs. Those become weaker and irregular on the following whorls. On the ultimate whorl, there are merely few growth stripes with wide smooth intermediate areas left. The ultimate whorls can display a blunt keel. Its base is slightly flattened.

The shell navel is open. The ultimate whorl is strongly elated. The shell mouth (aperture) is nearly circular, and the apertural rim is thickened and slightly folded to the outside. This outer area is divided into an inner and an outer part. On the inside, the apertural lip is thickened by a strong whitish lip. The palatal area is more or less brownish in colour. This lip, however, often is not completed.

In the shells of Cochlostoma henricae, a weak sexual dimorphism is visible. In females, the whorls are slightly more rounded. The shell coloured in a pale reddish to greyish brown tone. The surface is weakly glossy or may look slightly covered in a blue-grey colour frost. There are neither dark spots nor coloured bands visible.

The shells are similar to those of the Lesser Operculate Forest Snail (Cochlostoma septemspirale). In the latter species, however, the whorls are slightly more rounded.

Dimensions: H: 7.7 - 11.5 mm; W: 3.5 - 4.8 mm; N: 8½ - 9. Information: Abbreviations

 
Cochlostoma henricae: Liezen, Austria.
Photos: Alexander Mrkvicka (iNaturalist).		  
Habitat and Distribution: The Grey Operculate Forest Snail predominantly lives on calcareous rocks, and the animals are very tolerant to dryness. In the eastern Alps, Cochlostoma henricae can be found in altitudes as high as 2400 m MSL. The species' distribution area is limited to Northern Italy (Southern Alps) and Southeastern Austria (Eastern Alps).

Subspecies

In the species Cochlostoma henricae, two subspecies are usually distinguished:

Subspecies: Cochlostoma henricae huettneri (A. J. Wagner, 1897)

The shell of this subspecies of the Grey Operculate Forest Snail is of a yellowish horn-like colour and displays a pattern of three reddish brown bands dissolved into spots. Alternatively, there can also be reddish brown radial stripes. The surface ribs on the upper whorls are densely placed and pronounced, but becoming weaker towards the aperture. The shell rim is weakly bipartite and inside, the aperture displays a whitish lamella.

The subspecies in Upper Austria and Styria is limited to the Salzkammergut lake area. There it is found in altitudes of between 500 and 2000 m MSL.

Dimensions: H: 6.5 - 8.4 mm; W: 3 - 4 mm; N: 8. Information: Abbreviations

According to Hausdorf et al. (2024) (see below), the correct name of this subspecies rather is Cochlostoma henricae insigne (De Betta, 1870).

Edlinger, K.; Mildner, P. (1979): Monographie der in Kärnten lebenden Prosobranchiergattung Cochlostoma. In: Carinthia II. 169. Jahrgang, Klagenfurt. P. 281–304 (PDF).

Links
Literature

 


With Photos by Stefan Haller:
http://www.schneckenfoto.ch.

Latest Change: 09.10.2026 (Robert Nordsieck).
Latest Link Check: 08.10.2026.