vs Common Water Rat

Chrysococcus radians 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 (cordados)
Class	Chrysophyceae (Chrysophyceae)	Mammalia (mamíferos)
Order	Chromulinales (Chromulinales)	Rodentia (Rodents)
Family	Dinobryaceae	Muridae (Mice & Rats)
Genus	Chrysococcus	Hydromys
Species	Chrysococcus radians	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 and South America, inhabiting ecosystems characteristic of the region.

Range

Distributed across Brazil, Denmark, and Sweden.

Common Water Rat

Habitat

Typically found in diverse terrestrial and aquatic ecosystems.

Chrysococcus radians is a freshwater chrysophyte microalga in the genus Chrysococcus, class Chrysophyceae, order Chromulinales. The species epithet radians — radiating — describes a lorica with radiating spine-like projections or extensions emanating from the central body of the outer case, a morphological feature readily distinguishable under light microscopy. Radiating processes on chrysophyte loricas are thought to increase the effective surface area of the cell, potentially slowing sinking and maintaining the organism in the illuminated photic zone of freshwater lakes. C. radians has been documented from Norwegian and Swedish freshwater systems, with additional records from Denmark, consistent with a broader northern European distribution of this species. Scandinavian lakes, particularly the oligotrophic highland lakes of Norway and Sweden, harbor diverse chrysophyte communities in which Chrysococcus and related genera are frequently dominant components during spring and autumn mixing periods. The species inhabits the limnetic zone, where it engages in photosynthesis using the characteristic golden-brown chrysophyte pigments — chlorophylls a and c combined with fucoxanthin. Like other genus members, C. radians may also practice mixotrophic feeding on bacteria and dissolved organic matter, providing nutritional flexibility in oligotrophic environments. Siliceous stomatocysts produced by chrysophytes can survive in lake sediments and provide paleolimnological records of past environmental change. C. radians has not been evaluated under IUCN Red List criteria and is classified 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.