Common Metad vs Common Nut Truffle

Millardia meltada compared with Hymenogaster vulgaris

Key Differences

• Common Metad is Least Concern while Common Nut Truffle is Data Deficient.

Taxonomic Classification

Rank	Common Metad	Common Nut Truffle
Kingdom	Animalia (animal)	Fungi (Fungi)
Phylum	Chordata (Chordates)	Basidiomycota (Club Fungi)
Class	Mammalia (mammifères)	Agaricomycetes (Mushrooms)
Order	Rodentia (Rodents)	Agaricales (Gilled Mushrooms)
Family	Muridae (Mice & Rats)	Hymenogastraceae
Genus	Millardia	Hymenogaster
Species	Millardia meltada	Hymenogaster vulgaris

Conservation Status

Common Metad

LC — Least Concern

Common Nut Truffle

DD — Data Deficient

Physical Characteristics

Attribute	Common Metad	Common Nut Truffle
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Common Metad

Habitat

Typically found in diverse terrestrial and aquatic ecosystems.

Common Nut Truffle

Habitat

Typically found in forest floors, decomposing wood, and soil ecosystems.

Range

Distributed across Denmark, Norway, Portugal, Sweden, and United States.

Common Metad

The Common Metad (<em>Millardia meltada</em>) is a rodent belonging to the genus <em>Millardia</em> within the family Muridae. As a member of the Old World rats and mice, this species is typically found in diverse terrestrial and aquatic ecosystems across its range. The Common Metad is classified as Least Concern on the IUCN Red List, indicating that its populations are currently stable and not facing immediate extinction risk. Detailed biological traits such as body length, weight, and lifespan have not been widely documented for this species in available records. Its taxonomy places it within the order Rodentia, which encompasses a broad array of gnawing mammals adapted to a wide variety of ecological niches. While specific dietary habits are not well characterized in the available data, members of the genus <em>Millardia</em> are generally understood to be omnivorous, feeding on plant material and invertebrates typical of their habitat. Ongoing monitoring is important for ensuring this species maintains its current conservation standing.

Common Nut Truffle

<em>Hymenogaster vulgaris</em>, the common nut truffle, is a hypogeous (below-ground) fungus in the family Hymenogastraceae, order Agaricales. This sequestrate species produces enclosed, truffle-like fruiting bodies that mature underground and rely primarily on small mammals and invertebrates for spore dispersal, as the sporocarps never open to release spores aerially. <em>Hymenogaster vulgaris</em> typically forms ectomycorrhizal associations with hardwood tree species, particularly oaks and beeches, in temperate European forests. Its geographic range includes Denmark, Norway, Portugal, Sweden, and the United States, reflecting a somewhat scattered distribution across temperate zones. The species is currently assessed as Data Deficient by the IUCN, indicating that insufficient information exists to evaluate its conservation status, likely because hypogeous fungi are difficult to survey and their population trends are poorly known. Biological traits such as lifespan, body size, and diet remain poorly documented for this species. As an ectomycorrhizal fungus, <em>Hymenogaster vulgaris</em> plays a critical role in facilitating nutrient uptake in host trees and supporting forest health across its temperate range.