common bubble snail vs Greater knapweed

Akera bullata compared with Centaurea scabiosa

Key Differences

common bubble snail is Least Concern while Greater knapweed is Near Threatened.

Taxonomic Classification

Rank	common bubble snail	Greater knapweed
Kingdom	Animalia (Animals)	Plantae (Plants)
Phylum	Mollusca (Mollusks)	Magnoliophyta (Flowering Plants)
Class	Gastropoda (Gastropoda)	Magnoliopsida (Dicots)
Order	Aplysiida (Aplysiida)	Asterales (Daisies & Sunflowers)
Family	Akeridae	Asteraceae (Daisy Family)
Genus	Akera	Centaurea
Species	Akera bullata	Centaurea scabiosa

Conservation Status

common bubble snail

LC — Least Concern

Greater knapweed

NT — Near Threatened

Physical Characteristics

Attribute	common bubble snail	Greater knapweed
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

common bubble snail

Habitat

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

Range

Distributed across Denmark, Norway, Portugal, and Sweden.

Greater knapweed

Habitat

Typically found in diverse terrestrial habitats from tropical forests to temperate regions.

Range

Widely distributed across Europe (7 countries), North America (Canada, United States), and Oceania and the Pacific (Australia). Listed as Near Threatened, this species requires ongoing monitoring to prevent population decline.

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.