Brown Cobblestone Lichen vs common door snail

Acarospora fuscata compared with Clausilia bidentata

Taxonomic Classification

Rank	Brown Cobblestone Lichen	common door snail
Kingdom	Fungi (Fungi)	Animalia (Animals)
Phylum	Ascomycota (Sac Fungi)	Mollusca (Mollusks)
Class	Lecanoromycetes (Lecanoromycetes)	Gastropoda (Gastropoda)
Order	Acarosporales (Acarosporales)	Stylommatophora (Stylommatophora)
Family	Acarosporaceae	Clausiliidae
Genus	Acarospora	Clausilia
Species	Acarospora fuscata	Clausilia bidentata

Conservation Status

Brown Cobblestone Lichen

LC — Least Concern

common door snail

LC — Least Concern

Physical Characteristics

Attribute	Brown Cobblestone Lichen	common door snail
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Brown Cobblestone Lichen

Habitat

Native to Europe and North America, inhabiting ecosystems characteristic of the region.

Range

Distributed across Denmark, Norway, Portugal, and United States.

common door snail

Habitat

Typically found in terrestrial and aquatic habitats including forests and freshwater.

Range

Distributed across Belgium, Denmark, Norway, and Sweden.

Brown Cobblestone Lichen

The Brown Cobblestone Lichen (Acarospora fuscata) is a species in the genus Acarospora. It is currently classified as Least Concern on the IUCN Red List. Native to Europe and North America, inhabiting ecosystems characteristic of the region.

common door snail

<em>Clausilia bidentata</em>, the common door snail, is a terrestrial gastropod mollusk in the family Clausiliidae. This species is distributed across Belgium, Denmark, Norway, and Sweden, where it typically inhabits moist terrestrial environments including deciduous woodlands, rocky slopes, hedgerows, and the margins of freshwater habitats. The common door snail is recognized by its elongated, sinistral (left-handed) shell, which is a distinctive trait of the family Clausiliidae. The shell is typically brown to gray and reaches approximately 12–15 millimeters in length. <em>Clausilia bidentata</em> generally feeds on algae, lichens, fungi, and decaying plant material by rasping food with a radula. It often shelters under bark, stones, and leaf litter during dry or cold conditions. Like many clausiliids, it possesses a complex internal shell structure called a clausilium that closes the shell aperture to reduce desiccation. The species is assessed as Least Concern, reflecting stable populations across its European range. Detailed biological traits beyond those noted here are not extensively documented in the current scientific literature.

Shared Countries

Both species can be found in 2 countries:

🇩🇰 Denmark 🇳🇴 Norway