vs Common Water Rat

Chrysolykos complanatus 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	Ochrophyta (Ochrophyta)	Chordata (Chordates)
Class	Chrysophyceae (Chrysophyceae)	Mammalia (Mammals)
Order	Chromulinales (Chromulinales)	Rodentia (Rodents)
Family	Dinobryaceae	Muridae (Mice & Rats)
Genus	Chrysolykos	Hydromys
Species	Chrysolykos complanatus	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.

Chrysolykos complanatus is a freshwater chrysophyte microalga in the genus Chrysolykos, class Chrysophyceae. The species epithet complanatus — flattened or compressed — describes a lorica that is notably flattened in lateral view compared with the more three-dimensional forms of other Chrysolykos species. This flattened lorica morphology is the primary taxonomic character distinguishing C. complanatus from the angular C. angulatus and the boot-shaped C. calceatus within the small genus Chrysolykos. The loricate chrysophytes, including Chrysolykos, are characterized by cells enclosed within a species-specific outer case from which two flagella emerge — one directed anteriorly and one often wrapped around the cell — enabling swimming in aquatic environments. C. complanatus has been recorded from Norwegian and Swedish freshwater ecosystems, contributing to the known diversity of chrysophytes in cold Scandinavian lakes and pond habitats. These boreal and subarctic freshwater environments, often characterized by low pH, low nutrient concentrations, and high dissolved organic carbon from surrounding peat bogs, support characteristic chrysophyte assemblages in which loricate forms are frequently present. The species contributes to primary production as a photoautotroph and may supplement its carbon budget through bacterivory. Chrysolykos species are minor components of most phytoplankton communities and are not known to form blooms. C. complanatus has not been evaluated under IUCN Red List criteria and is listed as Not Evaluated.

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.