Coastal Silver-stiletto vs Common Button Lichen

Acrosathe annulata compared with Buellia erubescens

Key Differences

Coastal Silver-stiletto is Least Concern while Common Button Lichen is Not Evaluated.

Taxonomic Classification

Rank	Coastal Silver-stiletto	Common Button Lichen
Kingdom	Animalia (Animals)	Fungi (Fungi)
Phylum	Arthropoda (Arthropods)	Ascomycota (Sac Fungi)
Class	Insecta (Insects)	Lecanoromycetes (Lecanoromycetes)
Order	Diptera (Diptera)	Caliciales (Caliciales)
Family	Therevidae	Caliciaceae
Genus	Acrosathe	Buellia
Species	Acrosathe annulata	Buellia erubescens

Conservation Status

Coastal Silver-stiletto

LC — Least Concern

Common Button Lichen

NE — Not Evaluated

Physical Characteristics

Attribute	Coastal Silver-stiletto	Common Button Lichen
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.

Common Button Lichen

Habitat

Native to Asia and Europe and North America, inhabiting ecosystems characteristic of the region.

Range

Distributed across Norway, Portugal, Sweden, Taiwan, and United States.

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.

Common Button Lichen

<em>Buellia erubescens</em>, commonly known as the common button lichen, is a lichen species with documented occurrences across Asia, Europe, and North America, including countries such as Norway, Portugal, Sweden, Taiwan, and the United States. It typically colonizes diverse terrestrial surfaces, often found on bark, rock, or other substrates in temperate and boreal environments. Common button lichen belongs to the genus <em>Buellia</em> within the family Caliciaceae. As a crustose lichen, it typically forms tightly adhered, crust-like thalli on the surfaces it colonizes, making it characteristic of stable, undisturbed substrates. Biological traits such as average lifespan, thallus size, and biomass of this species remain poorly documented in the scientific literature. The species has not yet been formally evaluated by the IUCN, and its global conservation status therefore remains undetermined. Its occurrence across multiple continents suggests a wide ecological tolerance, though detailed population data and trend assessments are currently lacking for this taxon.