Coastal Silver-stiletto vs Collared Mosscap

Acrosathe annulata compared with Rickenella swartzii

Taxonomic Classification

Rank	Coastal Silver-stiletto	Collared Mosscap
Kingdom	Animalia (Animals)	Fungi (Fungi)
Phylum	Arthropoda (Arthropods)	Basidiomycota (Club Fungi)
Class	Insecta (Insects)	Agaricomycetes (Mushrooms)
Order	Diptera (Diptera)	Hymenochaetales (Hymenochaetales)
Family	Therevidae	Rickenellaceae
Genus	Acrosathe	Rickenella
Species	Acrosathe annulata	Rickenella swartzii

Conservation Status

Coastal Silver-stiletto

LC — Least Concern

Collared Mosscap

LC — Least Concern

Physical Characteristics

Attribute	Coastal Silver-stiletto	Collared Mosscap
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Coastal Silver-stiletto

Habitat

Typically found in virtually all terrestrial and freshwater habitats.

Range

Distributed across Belgium, Denmark, Norway, and Sweden.

Collared Mosscap

Habitat

Typically found in forest floors, decomposing wood, and soil ecosystems.

Range

Distributed across Belgium, Denmark, Norway, and Sweden.

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.

Collared Mosscap

The Collared Mosscap, known scientifically as <em>Rickenella swartzii</em>, is a small fungus belonging to the family Repetobasidiaceae within the order Agaricales. <em>Rickenella swartzii</em> is characterised by its diminutive fruiting bodies, which typically feature a small, convex to umbilicate cap and a slender stipe. The species typically grows in mossy substrates, on forest floors, decomposing wood, and soil, where it plays a role in nutrient cycling as a saprotrophic or potentially mycorrhizal organism. It is reported to occur in Belgium, Denmark, Norway, and Sweden, reflecting a distribution across parts of northern Europe. Detailed biological traits including typical lifespan measures and physical dimensions are poorly documented for this fungal species in available literature. The Collared Mosscap is currently assessed as Least Concern on the IUCN Red List, indicating that it is not considered to be at significant risk of global population decline.