vs common grey sea slug

Cliostomum leprosum compared with Aeolidia papillosa

Key Differences

is Vulnerable while common grey sea slug is Least Concern.

Taxonomic Classification

Rank		common grey sea slug
Kingdom	Fungi (Fungi)	Animalia (Animals)
Phylum	Ascomycota (Sac Fungi)	Mollusca (Mollusks)
Class	Lecanoromycetes (Lecanoromycetes)	Gastropoda (Gastropoda)
Order	Lecanorales (Lecanorales)	Nudibranchia (Nudibranchia)
Family	Ramalinaceae	Aeolidiidae
Genus	Cliostomum	Aeolidia
Species	Cliostomum leprosum	Aeolidia papillosa

Conservation Status

VU — Vulnerable

common grey sea slug

LC — Least Concern

Physical Characteristics

Attribute		common grey sea slug
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Habitat

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

Range

Distributed across Norway, Sweden, and United States. Currently classified as Vulnerable on the IUCN Red List, this species faces significant conservation challenges across its 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.

Cliostomum leprosum is a crustose lichen-forming fungus in the family Ramalinaceae, notable for its powdery, leprose thallus that gives it a granular, mealy appearance on bark and wood substrates. Unlike many lichens that form well-defined, structured thalli, C. leprosum produces a loosely coherent sorediose crust ranging from pale greenish-grey to whitish, often colonizing deeply shaded, moist bark on deciduous and coniferous trees. The species is distributed across boreal and temperate forests of Europe and North America, with confirmed records from Norway, Sweden, and scattered locations in the United States. It photosynthesizes in partnership with green algal partners typical of crustose lichens. Cliostomum leprosum is assessed as Vulnerable due to its sensitivity to air pollution, particularly sulfur dioxide and nitrogen compounds that degrade lichen communities. Its decline is linked to habitat loss from intensive forestry, removal of veteran trees, and acidic deposition. Conservation efforts focus on preserving old-growth and semi-natural forest stands that provide suitable, low-disturbance bark microhabitats where this inconspicuous but ecologically significant lichen can persist.

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.