Common Button Lichen vs Common Water Rat

Buellia erubescens compared with Hydromys chrysogaster

Key Differences

• Common Button Lichen is Not Evaluated while Common Water Rat is Least Concern.

Taxonomic Classification

Rank	Common Button Lichen	Common Water Rat
Kingdom	Fungi (Fungi)	Animalia (Animals)
Phylum	Ascomycota (Sac Fungi)	Chordata (Chordates)
Class	Lecanoromycetes (Lecanoromycetes)	Mammalia (Mammals)
Order	Caliciales (Caliciales)	Rodentia (Rodents)
Family	Caliciaceae	Muridae (Mice & Rats)
Genus	Buellia	Hydromys
Species	Buellia erubescens	Hydromys chrysogaster

Conservation Status

Common Button Lichen

NE — Not Evaluated

Common Water Rat

LC — Least Concern

Physical Characteristics

Attribute	Common Button Lichen	Common Water Rat
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Common Button Lichen

Habitat

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

Range

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

Common Water Rat

Habitat

Typically found in diverse terrestrial and aquatic ecosystems.

Common Button Lichen

<em>Buellia erubescens</em>, commonly known as the common button lichen, is a lichen species with documented occurrences across Asia, Europe, and North America, including countries such as Norway, Portugal, Sweden, Taiwan, and the United States. It typically colonizes diverse terrestrial surfaces, often found on bark, rock, or other substrates in temperate and boreal environments. Common button lichen belongs to the genus <em>Buellia</em> within the family Caliciaceae. As a crustose lichen, it typically forms tightly adhered, crust-like thalli on the surfaces it colonizes, making it characteristic of stable, undisturbed substrates. Biological traits such as average lifespan, thallus size, and biomass of this species remain poorly documented in the scientific literature. The species has not yet been formally evaluated by the IUCN, and its global conservation status therefore remains undetermined. Its occurrence across multiple continents suggests a wide ecological tolerance, though detailed population data and trend assessments are currently lacking for this taxon.

Common Water Rat

<em>Hydromys chrysogaster</em>, commonly known as the common water rat or rakali, is a semi-aquatic rodent in the family Muridae, native to Australia and New Guinea. It is classified as Least Concern by the IUCN, reflecting its relatively stable population across a broad range of freshwater and estuarine habitats on the Australian continent and associated islands. The species typically inhabits the banks of rivers, lakes, wetlands, and estuaries, where it constructs burrows in streambanks. It is highly adapted for an aquatic lifestyle, with partially webbed hind feet, a flattened head, and a dense waterproof coat. <em>Hydromys chrysogaster</em> is a carnivore, typically feeding on fish, crustaceans, mussels, frogs, and aquatic invertebrates, which it often carries to elevated feeding platforms to consume. The species is nocturnal and crepuscular, most active during early morning and evening hours near the water's edge. Biological traits including average lifespan, body length, and weight remain poorly documented in standardized databases, though adults are generally robust for a rodent, reportedly reaching body lengths of 20–35 cm excluding the tail. Geographic range details for this particular record remain incompletely documented in available data sources. Ecologically, the common water rat is an important apex predator in small-scale freshwater food webs and serves as an indicator species for wetland health in Australian riparian systems.