vs Common Water Rat

Chroomonas extensa compared with Hydromys chrysogaster

Key Differences

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

Taxonomic Classification

Rank		Common Water Rat
Kingdom	Chromista (Chromista)	Animalia (Animals)
Phylum	Cryptophyta	Chordata (Chordates)
Class	Cryptophyceae (Cryptophyceae)	Mammalia (Mammals)
Order	Pyrenomonadales (Pyrenomonadales)	Rodentia (Rodents)
Family	Chroomonadaceae	Muridae (Mice & Rats)
Genus	Chroomonas	Hydromys
Species	Chroomonas extensa	Hydromys chrysogaster

Conservation Status

NE — Not Evaluated

Common Water Rat

LC — Least Concern

Physical Characteristics

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

Habitat & Geographic Range

Habitat

Native to Europe, inhabiting ecosystems characteristic of the region.

Range

Distributed across Norway and Sweden.

Common Water Rat

Habitat

Typically found in diverse terrestrial and aquatic ecosystems.

Chroomonas extensa is a species of cryptophyte alga in the family Chroomonadaceae, documented from freshwater environments in Europe. The specific epithet extensa refers to an extended or elongated cell morphology relative to other Chroomonas species. Cell shape and proportions are important diagnostic characters within the genus Chroomonas, where species are distinguished by cell dimensions, color, flagellar arrangement, and the structure of the ejectosomes — coiled proteinaceous organelles unique to cryptophytes that can be discharged rapidly, perhaps for predator avoidance. Cryptophytes of the genus Chroomonas are important primary producers in freshwater phytoplankton communities, particularly in cold-water periods when they may contribute substantially to total algal biomass. They are also important food sources in microbial food webs, supporting populations of heterotrophic flagellates and ciliates that consume them and transfer energy to higher trophic levels. Chroomonas extensa has been recorded from European freshwater localities. Like other microalgal species, it has not been assessed by the IUCN under formal conservation criteria.

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.