Chocolate arion vs Chunky False Brook Salamander

Arion rufus compared with Aquiloeurycea cephalica

Key Differences

• Chocolate arion is Vulnerable while Chunky False Brook Salamander is Least Concern.

Taxonomic Classification

Rank	Chocolate arion	Chunky False Brook Salamander
Kingdom same	Animalia (Animals)	Animalia (Animals)
Phylum	Mollusca (Mollusks)	Chordata (Chordates)
Class	Gastropoda (Gastropoda)	Amphibia (Amphibians)
Order	Stylommatophora (Stylommatophora)	Caudata (Caudata)
Family	Arionidae	Plethodontidae
Genus	Arion	Aquiloeurycea
Species	Arion rufus	Aquiloeurycea cephalica

Evolutionary Relationship

Chocolate arion and Chunky False Brook Salamander share a common ancestor at the Kingdom level: Animalia. (Animals)

Conservation Status

Chocolate arion

VU — Vulnerable

Chunky False Brook Salamander

LC — Least Concern

Physical Characteristics

Attribute	Chocolate arion	Chunky False Brook Salamander
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Chocolate arion

Habitat

Inhabits temperate broadleaf and mixed forests and Mediterranean forests and woodlands within the Palearctic biogeographic realm. Populations are also found in montane and highland environments at higher elevations.

Range

Found across Europe (7 countries) and North America (United States). Currently classified as Vulnerable on the IUCN Red List, this species faces significant conservation challenges across its range.

Chunky False Brook Salamander

Habitat

Typically found in freshwater habitats, moist forests, and wetlands.

Range

Found in Mexico.

Chocolate arion

The Chocolate Arion (Arion rufus), also known as the Large Red Slug or Chocolate Slug, is one of Europe's largest terrestrial slugs, with adults reaching up to 15 centimetres in length. It belongs to the family Arionidae within the phylum Mollusca, and despite its common name, adults display highly variable colouration ranging from reddish-orange to dark brown and nearly black — only certain colour morphs exhibit the chocolate-brown hue that partly inspired the name. Arion rufus is native to western and central Europe, where it inhabits woodland, hedgerows, gardens, agricultural land, and other moist habitats. It is also established as an introduced species in parts of North America. Like other arionid slugs, it is primarily a detritivore and herbivore, consuming dead plant material, fungi, living plant tissue, and sometimes carrion. It shelters under logs, stones, and leaf litter during dry or cold conditions, becoming active — particularly at night — during warm, moist weather. Chocolate arion can cause significant damage to gardens and crops. Reproduction is hermaphroditic; slugs exchange sperm and lay batches of translucent eggs in soil or under debris. The IUCN classifies this species as Vulnerable, reflecting pressures on native European populations from habitat change and, possibly, competition and hybridisation with related Arion species.

Chunky False Brook Salamander

The Chunky False Brook Salamander (Aquiloeurycea cephalica) is a Least Concern plethodontid salamander endemic to Mexico, found in cloud forest and humid montane habitats in the Sierra Madre Oriental and related mountain ranges. The genus Aquiloeurycea is a recently erected Mexican endemic genus segregated from the broader genus Pseudoeurycea, comprising several small, robustly built (hence 'chunky') salamanders associated with high-elevation forests. Like all plethodontids, A. cephalica is a lungless salamander that breathes entirely through its moist, vascularized skin and the lining of its mouth. It is a direct developer, skipping the aquatic larval stage entirely and laying eggs in terrestrial microhabitats such as rotting logs, leaf litter, and soil. A. cephalica inhabits cool, humid forests of pine-oak and cloud forest zones in northern Mexico, where it forages for small invertebrates in the leaf litter and soil. The IUCN assesses it as Least Concern due to its reasonably wide distribution within its montane range. Deforestation, cattle grazing, and the conversion of cloud forest to agriculture represent ongoing threats to populations throughout its range.