common freshwater nerite vs Eurasian Skylark

Theodoxus fluviatilis compared with Alauda arvensis

Key Differences

• common freshwater nerite is Least Concern while Eurasian Skylark is Vulnerable.

Taxonomic Classification

Rank	common freshwater nerite	Eurasian Skylark
Kingdom same	Animalia (Animals)	Animalia (Animals)
Phylum	Mollusca (Mollusks)	Chordata (Chordates)
Class	Gastropoda (Gastropoda)	Aves (Birds)
Order	Cycloneritida (Cycloneritida)	Passeriformes (Songbirds)
Family	Neritidae	Alaudidae
Genus	Theodoxus	Alauda
Species	Theodoxus fluviatilis	Alauda arvensis

Evolutionary Relationship

common freshwater nerite and Eurasian Skylark share a common ancestor at the Kingdom level: Animalia. (Animals)

Conservation Status

common freshwater nerite

LC — Least Concern

Eurasian Skylark

VU — Vulnerable

Physical Characteristics

Attribute	common freshwater nerite	Eurasian Skylark
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).

Eurasian Skylark

Habitat

Found across multiple habitat types including temperate broadleaf and mixed forests, tundra, and tropical and subtropical moist broadleaf forests spanning the Australasia and Oceanian realms.

Range

Widely distributed across Europe (5 countries), North America (Canada, United States), and Oceania and the Pacific (Australia, New Zealand). Currently classified as Vulnerable on the IUCN Red List, this species faces significant conservation challenges across its range.

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.

Eurasian Skylark

Celebrated across European literature and poetry for its complex, melodious song sung on the wing during spectacular display flights, Eurasian skylarks soar vertically hundreds of meters above open farmland, grassland, and heathland across Europe and Asia while producing an uninterrupted torrent of song lasting up to an hour. Males can produce over 700 distinct song phrases. Once enormously abundant across European farmland, skylark populations have declined over 70% since 1970 due to agricultural intensification.

Shared Countries

Both species can be found in 4 countries:

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