Black-Lined Periwinkle vs Coastal Silver-stiletto

Littorina saxatilis compared with Acrosathe annulata

Taxonomic Classification

Rank	Black-Lined Periwinkle	Coastal Silver-stiletto
Kingdom same	Animalia (Animals)	Animalia (Animals)
Phylum	Mollusca (Mollusks)	Arthropoda (Arthropods)
Class	Gastropoda (Gastropoda)	Insecta (Insects)
Order	Littorinimorpha (Littorinimorpha)	Diptera (Diptera)
Family	Littorinidae	Therevidae
Genus	Littorina	Acrosathe
Species	Littorina saxatilis	Acrosathe annulata

Evolutionary Relationship

Black-Lined Periwinkle and Coastal Silver-stiletto share a common ancestor at the Kingdom level: Animalia. (Animals)

Conservation Status

Black-Lined Periwinkle

LC — Least Concern

Coastal Silver-stiletto

LC — Least Concern

Physical Characteristics

Attribute	Black-Lined Periwinkle	Coastal Silver-stiletto
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Black-Lined Periwinkle

Habitat

Found across multiple habitat types including tropical and subtropical grasslands and savannas, flooded grasslands and savannas, and deserts and xeric shrublands within the Afrotropic biogeographic realm.

Range

Widely distributed across Africa (Namibia, South Africa), Europe (5 countries), and North America (United States).

Coastal Silver-stiletto

Habitat

Typically found in virtually all terrestrial and freshwater habitats.

Range

Distributed across Belgium, Denmark, Norway, and Sweden.

Black-Lined Periwinkle

The Black-Lined Periwinkle (Littorina saxatilis) is a species in the genus Littorina. It is currently classified as Least Concern on the IUCN Red List. Found across multiple habitat types including tropical and subtropical grasslands and savannas, flooded grasslands and savannas, and deserts and xeric shrublands within the Afrotropic biogeographic realm.

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.

Shared Countries

Both species can be found in 3 countries:

🇩🇰 Denmark 🇳🇴 Norway 🇸🇪 Sweden