common razor clam vs small tortoiseshell

Ensis ensis compared with Aglais urticae

Key Differences

• common razor clam is Least Concern while small tortoiseshell is Near Threatened.

Taxonomic Classification

Rank	common razor clam	small tortoiseshell
Kingdom same	Animalia (Animals)	Animalia (Animals)
Phylum	Mollusca (Mollusks)	Arthropoda (Arthropods)
Class	Bivalvia (Bivalvia)	Insecta (Insects)
Order	Adapedonta (Adapedonta)	Lepidoptera (Butterflies & Moths)
Family	Pharidae	Nymphalidae (Brush-footed Butterflies)
Genus	Ensis	Aglais
Species	Ensis ensis	Aglais urticae

Evolutionary Relationship

common razor clam and small tortoiseshell share a common ancestor at the Kingdom level: Animalia. (Animals)

Conservation Status

common razor clam

LC — Least Concern

small tortoiseshell

NT — Near Threatened

Physical Characteristics

Attribute	common razor clam	small tortoiseshell
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

common razor clam

Habitat

Native to Europe, inhabiting ecosystems characteristic of the region.

Range

Distributed across Belgium, Denmark, Norway, and Sweden.

small tortoiseshell

Habitat

Typically found in virtually all terrestrial and freshwater habitats.

Range

Found across Europe (41 countries). Listed as Near Threatened, this species requires ongoing monitoring to prevent population decline.

common razor clam

<em>Ensis ensis</em>, the common razor clam, is a bivalve mollusk in the family Pharidae, order Adapedonta. It is distributed along the northeastern Atlantic coastline, with documented populations in Belgium, Denmark, Norway, and Sweden. The species is assessed as Least Concern by the IUCN, suggesting stable populations across much of its range. Common razor clams typically inhabit sandy intertidal and shallow subtidal zones, burrowing rapidly into sediment using their muscular foot to evade predators and avoid desiccation. Their elongated shell, resembling an old-fashioned straight razor, is a distinctive morphological feature of the genus Ensis. <em>Ensis ensis</em> is a suspension feeder, typically drawing in water and filtering phytoplankton and organic particles through its siphons. This feeding strategy makes it an important component of coastal benthic communities. Razor clams play an ecological role as both filter feeders improving water clarity and as prey items for shorebirds, flatfish, and marine mammals. Biological traits such as precise lifespan, body measurements, and diet composition vary across populations and remain incompletely characterized. The species is commercially harvested in parts of its range and is considered a minor fishery resource in Scandinavian waters.

small tortoiseshell

small tortoiseshell (Aglais urticae) is classified as Near Threatened (NT) on the IUCN Red List. Close to qualifying as threatened, with populations that may become vulnerable without conservation action.

Shared Countries

Both species can be found in 4 countries:

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