vs Coastal Silver-stiletto

Chroococcus planctonicus compared with Acrosathe annulata

Key Differences

is Not Evaluated while Coastal Silver-stiletto is Least Concern.

Taxonomic Classification

Rank		Coastal Silver-stiletto
Kingdom	Bacteria (Bacteria)	Animalia (Animals)
Phylum	Cyanobacteria (Cyanobacteria)	Arthropoda (Arthropods)
Class	Cyanobacteriia	Insecta (Insects)
Order	Cyanobacteriales	Diptera (Diptera)
Family	Microcystaceae	Therevidae
Genus	Chroococcus	Acrosathe
Species	Chroococcus planctonicus	Acrosathe annulata

Conservation Status

NE — Not Evaluated

Coastal Silver-stiletto

LC — Least Concern

Physical Characteristics

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

Habitat & Geographic Range

Habitat

Native to Europe, inhabiting ecosystems characteristic of the region.

Range

Distributed across Norway and Sweden.

Coastal Silver-stiletto

Habitat

Typically found in virtually all terrestrial and freshwater habitats.

Range

Distributed across Belgium, Denmark, Norway, and Sweden.

Chroococcus planctonicus is a species of cyanobacteria in the family Chroococcaceae, adapted to the planktonic lifestyle suggested by its specific epithet. Unlike some Chroococcus species that are primarily benthic or periphytic — attached to substrates — Chroococcus planctonicus is characteristic of open-water plankton communities in freshwater lakes and ponds. Planktonic cyanobacteria must maintain a position in the water column for optimal light exposure, and some have evolved gas vesicles to regulate buoyancy, though these are more developed in filamentous bloom-forming genera. Chroococcus planctonicus cells are spherical, occurring in pairs or tetrads within gelatinous sheaths, following the basic morphological plan of the genus. It has been documented from European freshwater systems including Swedish and Finnish lakes, where it contributes to the seasonal phytoplankton community. Cyanobacteria are important primary producers in freshwater ecosystems, particularly in summer when warm temperatures and stratified water columns favor their growth. However, Chroococcus planctonicus is not generally associated with harmful algal blooms, which are more characteristic of genera such as Microcystis and Anabaena. Its conservation status has not been assessed.

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.