common freshwater nerite vs koala

Theodoxus fluviatilis compared with Phascolarctos cinereus

Key Differences

• common freshwater nerite is Least Concern while koala is Vulnerable.

Taxonomic Classification

Rank	common freshwater nerite	koala
Kingdom same	Animalia (Animals)	Animalia (Animals)
Phylum	Mollusca (Mollusks)	Chordata (Chordates)
Class	Gastropoda (Gastropoda)	Mammalia (Mammals)
Order	Cycloneritida (Cycloneritida)	Diprotodontia (Marsupials)
Family	Neritidae	Phascolarctidae (Koalas)
Genus	Theodoxus	Phascolarctos (Koalas)
Species	Theodoxus fluviatilis	Phascolarctos cinereus

Evolutionary Relationship

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

Conservation Status

common freshwater nerite

LC — Least Concern

koala

VU — Vulnerable

Population: ~100.0K

Trend: Decreasing ↓

Physical Characteristics

Attribute	common freshwater nerite	koala
Diet	—	Herbivore
Average Lifespan	—	15 years
Average Length	—	75 cm
Average Weight	—	10.0 kg

Habitat & Geographic Range

common freshwater nerite

Habitat

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

Range

Found across Europe (11 countries).

koala

Habitat

Typically found in grasslands, forests, and vegetated habitats.

Range

Found in Australia. 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.

koala

Iconic marsupial of eastern and southeastern Australia, koalas weigh up to 15 kg and spend up to 22 hours daily sleeping to conserve energy from their low-calorie eucalyptus leaf diet. Highly specialized to process toxic eucalyptus compounds that would kill most other mammals, they have gut microbiomes uniquely adapted for detoxification. Listed as Endangered in 2022, with populations decimated by chlamydia disease, habitat clearing, and climate change.