Arrow-head tree snail vs Coastal Silver-stiletto

Partula sagitta compared with Acrosathe annulata

Key Differences

• Arrow-head tree snail is Extinct while Coastal Silver-stiletto is Least Concern.

Taxonomic Classification

Rank	Arrow-head tree snail	Coastal Silver-stiletto
Kingdom same	Animalia (Animals)	Animalia (Animals)
Phylum	Mollusca (Mollusks)	Arthropoda (Arthropods)
Class	Gastropoda (Gastropoda)	Insecta (Insects)
Order	Stylommatophora (Stylommatophora)	Diptera (Diptera)
Family	Partulidae	Therevidae
Genus	Partula	Acrosathe
Species	Partula sagitta	Acrosathe annulata

Evolutionary Relationship

Arrow-head tree snail and Coastal Silver-stiletto share a common ancestor at the Kingdom level: Animalia. (Animals)

Conservation Status

Arrow-head tree snail

EX — Extinct

Coastal Silver-stiletto

LC — Least Concern

Physical Characteristics

Attribute	Arrow-head tree snail	Coastal Silver-stiletto
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Arrow-head tree snail

Habitat

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

Coastal Silver-stiletto

Habitat

Typically found in virtually all terrestrial and freshwater habitats.

Range

Distributed across Belgium, Denmark, Norway, and Sweden.

Arrow-head tree snail

The Arrow-head tree snail, Partula sagitta, is a species. It is currently assessed as extinct on the IUCN Red List. Typically found in terrestrial and aquatic habitats including forests and freshwater.

Coastal Silver-stiletto

Coastal silver stiletto (Acrosathe annulata) is a slender robber fly in the family Therevidae, native to northwestern Europe, including the United Kingdom, France, the Netherlands, Belgium, and Scandinavia. Adults are found on coastal sand dunes and sandy heathland, where they perch on bare sand to ambush small flying insects. Stiletto flies in the family Therevidae are characterised by a slender body, long pointed abdomen, and predatory habits; adults prey on a variety of small dipterans and other flying insects during warm, sunny periods. Larvae develop in sandy soil, where they are also predatory, feeding on other invertebrate larvae. Acrosathe annulata is a habitat specialist restricted to open, sandy coastal habitats with sparse vegetation—environments that have declined substantially across northwestern Europe due to dune stabilisation, recreational disturbance, and the cessation of traditional dune management. The IUCN lists it as Least Concern, though regional conservation bodies in the United Kingdom have flagged population declines. It is considered an indicator of high-quality coastal sand dune habitats and is monitored through national invertebrate surveys.