common grey sea slug vs St. James' shell

Aeolidia papillosa compared with Pecten maximus

Taxonomic Classification

Rank	common grey sea slug	St. James' shell
Kingdom same	Animalia (Animals)	Animalia (Animals)
Phylum same	Mollusca (Mollusks)	Mollusca (Mollusks)
Class	Gastropoda (Gastropoda)	Bivalvia (Bivalvia)
Order	Nudibranchia (Nudibranchia)	Pectinida (Pectinida)
Family	Aeolidiidae	Pectinidae
Genus	Aeolidia	Pecten
Species	Aeolidia papillosa	Pecten maximus

Evolutionary Relationship

common grey sea slug and St. James' shell share a common ancestor at the Phylum level: Mollusca. (Mollusks)

Conservation Status

common grey sea slug

LC — Least Concern

St. James' shell

LC — Least Concern

Physical Characteristics

Attribute	common grey sea slug	St. James' shell
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

common grey sea slug

Habitat

Typically found in terrestrial and aquatic habitats including forests and freshwater.

Range

Distributed across Belgium, Chile, Denmark, Norway, and Sweden.

St. James' shell

Habitat

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

Range

Widely distributed across Asia (China), Europe (8 countries), and South America (Chile).

common grey sea slug

<em>Aeolidia papillosa</em>, commonly known as the common grey sea slug, is a nudibranch mollusc belonging to the genus Aeolidia within the family Aeolidiidae. Despite the species name referencing terrestrial and aquatic habitats including forests and freshwater, <em>Aeolidia papillosa</em> is primarily a marine organism. Its range includes Belgium, Chile, Denmark, Norway, and Sweden, indicating a distribution across the North Atlantic and into South American waters. Common grey sea slug is assessed as Least Concern on the IUCN Red List. The species is typically found in intertidal and subtidal zones, where it preys on sea anemones and stores stinging cells from its prey in its dorsal cerata for defense. Biological traits of this species remain poorly documented in the scientific literature.

St. James' shell

St. James' shell (Pecten maximus) is classified as Least Concern (LC) on the IUCN Red List. Widespread and abundant across its range, with stable populations and no immediate conservation concerns.

Shared Countries

Both species can be found in 5 countries:

🇧🇪 Belgium 🇨🇱 Chile 🇩🇰 Denmark 🇳🇴 Norway 🇸🇪 Sweden