Big Finner vs Coastal Silver-stiletto

Balaenoptera physalus compared with Acrosathe annulata

Key Differences

• Big Finner is Endangered while Coastal Silver-stiletto is Least Concern.

Taxonomic Classification

Rank	Big Finner	Coastal Silver-stiletto
Kingdom same	Animalia (động vật)	Animalia (động vật)
Phylum	Chordata (động vật có dây sống)	Arthropoda (động vật Chân khớp)
Class	Mammalia (lớp Thú)	Insecta (côn trùng)
Order	Cetacea (Whales & Dolphins)	Diptera (Ruồi)
Family	Balaenopteridae (Rorquals)	Therevidae
Genus	Balaenoptera (Rorquals)	Acrosathe
Species	Balaenoptera physalus	Acrosathe annulata

Evolutionary Relationship

Big Finner and Coastal Silver-stiletto share a common ancestor at the Kingdom level: Animalia. (động vật)

Conservation Status

Big Finner

EN — Endangered

Coastal Silver-stiletto

LC — Least Concern

Physical Characteristics

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

Habitat & Geographic Range

Big Finner

Habitat

Found across multiple habitat types including tropical and subtropical dry broadleaf forests, flooded grasslands and savannas, and montane grasslands and shrublands, among 4 distinct biome types within the Neotropic biogeographic realm.

Range

Widely distributed across Asia (Taiwan), Europe (5 countries), and South America (Colombia, Ecuador, Venezuela). Currently classified as Endangered on the IUCN Red List, this species faces significant conservation challenges across its range.

Coastal Silver-stiletto

Habitat

Typically found in virtually all terrestrial and freshwater habitats.

Range

Distributed across Belgium, Denmark, Norway, and Sweden.

Big Finner

Big Finner (Balaenoptera physalus) is classified as Endangered (EN) on the IUCN Red List. At high risk of extinction in the wild, with significant population decline and ongoing threats to survival.

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 4 countries:

🇧🇪 Belgium 🇩🇰 Denmark 🇳🇴 Norway 🇸🇪 Sweden