common freshwater nerite vs Common harp ground beetle

Theodoxus fluviatilis compared with Amara communis

Taxonomic Classification

Rank	common freshwater nerite	Common harp ground beetle
Kingdom same	Animalia (Animals)	Animalia (Animals)
Phylum	Mollusca (Mollusks)	Arthropoda (Arthropods)
Class	Gastropoda (Gastropoda)	Insecta (Insects)
Order	Cycloneritida (Cycloneritida)	Coleoptera (Beetles)
Family	Neritidae	Carabidae
Genus	Theodoxus	Amara
Species	Theodoxus fluviatilis	Amara communis

Evolutionary Relationship

common freshwater nerite and Common harp ground beetle share a common ancestor at the Kingdom level: Animalia. (Animals)

Conservation Status

common freshwater nerite

LC — Least Concern

Common harp ground beetle

LC — Least Concern

Physical Characteristics

Attribute	common freshwater nerite	Common harp ground beetle
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

common freshwater nerite

Habitat

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

Range

Found across Europe (11 countries).

Common harp ground beetle

Habitat

Typically found in virtually all terrestrial and freshwater habitats.

Range

Found across Europe (5 countries) and North America (Canada, United States).

common freshwater nerite

<em>Theodoxus fluviatilis</em>, commonly known as the common freshwater nerite, is a small aquatic gastropod mollusc belonging to the family Neritidae. This species is widely distributed across Europe, with documented occurrences in Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Hungary, Latvia, Norway, and Sweden. It typically inhabits freshwater environments, including rivers, streams, and lakes, where it grazes on algae and biofilm on hard substrates such as rocks and submerged wood. The common freshwater nerite is assessed as Least Concern on conservation metrics, reflecting its broad distribution and relatively stable populations across much of its European range. Biological traits of this species remain poorly documented in the scientific literature. <em>Theodoxus fluviatilis</em> plays an ecological role as a grazer in freshwater benthic communities, contributing to the regulation of algal growth on hard surfaces. The species typically favors clean, well-oxygenated waters and can serve as an indicator of water quality in freshwater systems. Its distinctive small, dome-shaped shell with variable patterning makes it recognizable among freshwater invertebrates.

Common harp ground beetle

The common harp ground beetle, <em>Amara communis</em>, is an insect belonging to the order Coleoptera, family Carabidae, the ground beetles. This species is distributed across Europe and North America, indicating a wide Holarctic range. Ground beetles of the genus Amara are typically found in a variety of terrestrial habitats including grasslands, agricultural fields, woodland margins, and disturbed areas. Members of this genus are generally omnivorous or seed-feeding, and some are known to consume weed seeds, giving them potential ecological significance in agroecosystems. <em>Amara communis</em> is assessed as Least Concern on the IUCN Red List, reflecting stable populations across its range. No dietary information has been provided specifically for this species in current records. Biological traits of this species remain poorly documented in the scientific literature.

Shared Countries

Both species can be found in 4 countries:

🇧🇪 Belgium 🇩🇰 Denmark 🇳🇴 Norway 🇸🇪 Sweden