Chalk Screw-moss vs common bubble snail

Tortula vahliana compared with Akera bullata

Key Differences

Chalk Screw-moss is Vulnerable while common bubble snail is Least Concern.

Taxonomic Classification

Rank	Chalk Screw-moss	common bubble snail
Kingdom	Plantae (Plants)	Animalia (Animals)
Phylum	Bryophyta	Mollusca (Mollusks)
Class	Bryopsida (Bryopsida)	Gastropoda (Gastropoda)
Order	Pottiales (Pottiales)	Aplysiida (Aplysiida)
Family	Pottiaceae	Akeridae
Genus	Tortula	Akera
Species	Tortula vahliana	Akera bullata

Conservation Status

Chalk Screw-moss

VU — Vulnerable

common bubble snail

LC — Least Concern

Physical Characteristics

Attribute	Chalk Screw-moss	common bubble snail
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Chalk Screw-moss

Habitat

Native to Europe, inhabiting ecosystems characteristic of the region.

Range

Distributed across Belgium, Norway, and Portugal. Currently classified as Vulnerable on the IUCN Red List, this species faces significant conservation challenges across its range.

common bubble snail

Habitat

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

Range

Distributed across Denmark, Norway, Portugal, and Sweden.

Chalk Screw-moss

The Chalk Screw-moss (Tortula vahliana) is a species in the genus Tortula. It is currently classified as Vulnerable on the IUCN Red List. Native to Europe, inhabiting ecosystems characteristic of the region.

common bubble snail

The common bubble snail (<em>Akera bullata</em>) is a marine gastropod mollusc found in the coastal waters of Denmark, Norway, Portugal, and Sweden. This species typically inhabits terrestrial and aquatic environments including forests and freshwater-adjacent marine areas, often occurring in shallow subtidal and intertidal zones of temperate European seas. It is classified as Least Concern on the IUCN Red List. As a member of the family Akeridae, the common bubble snail is characterized by its thin, fragile shell and its ability to swim briefly by flapping its large, wing-like parapodia. The species often forages on algae and detritus in sandy and muddy seafloor habitats, particularly in sheltered bays and estuaries. The common bubble snail typically aggregates in large numbers during the spawning season, producing gelatinous egg masses. Biological traits of this species remain poorly documented in the scientific literature.