Collared Earthstar vs Common Water Rat

Geastrum triplex compared with Hydromys chrysogaster

Key Differences

• Collared Earthstar is Near Threatened while Common Water Rat is Least Concern.

Taxonomic Classification

Rank	Collared Earthstar	Common Water Rat
Kingdom	Fungi (Fungi)	Animalia (Animals)
Phylum	Basidiomycota (Club Fungi)	Chordata (Chordates)
Class	Agaricomycetes (Mushrooms)	Mammalia (Mammals)
Order	Geastrales (Geastrales)	Rodentia (Rodents)
Family	Geastraceae	Muridae (Mice & Rats)
Genus	Geastrum	Hydromys
Species	Geastrum triplex	Hydromys chrysogaster

Conservation Status

Collared Earthstar

NT — Near Threatened

Common Water Rat

LC — Least Concern

Physical Characteristics

Attribute	Collared Earthstar	Common Water Rat
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Collared Earthstar

Habitat

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

Range

Distributed across Belgium, Brazil, Norway, and United States. Listed as Near Threatened, this species requires ongoing monitoring to prevent population decline.

Common Water Rat

Habitat

Typically found in diverse terrestrial and aquatic ecosystems.

Collared Earthstar

<em>Geastrum triplex</em>, the Collared Earthstar, is a gasteroid fungus in the family Geastraceae, order Geastrales. This species is assessed as Near Threatened on the IUCN Red List, indicating that it may be at risk of qualifying for a threatened category in the near future. It has been recorded in Belgium, Brazil, Norway, and the United States, and is associated with forest floors, decomposing wood, and soil. Earthstars in the genus <em>Geastrum</em> are recognized by their distinctive star-shaped fruiting bodies, formed when the outer wall splits and folds back into ray-like segments to reveal an inner spore sac. <em>Geastrum triplex</em> is distinguished by the formation of a collar or cup-like structure around the base of the inner spore sac, which gives rise to its common name. Like other gasteroid fungi, it disperses spores through an apical pore in the spore sac. Population estimates and trend data are not available. Biological traits of this species remain poorly documented in the scientific literature. Its Near Threatened status may reflect sensitivity to habitat disturbance and forest management practices.

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.