vs Common Fat-tailed Mouse Opossum

Chrysococcus bisetus compared with Thylamys pusillus

Key Differences

• is Not Evaluated while Common Fat-tailed Mouse Opossum is Least Concern.

Taxonomic Classification

Rank		Common Fat-tailed Mouse Opossum
Kingdom	Chromista (Chromista)	Animalia (Animals)
Phylum	Ochrophyta (Ochrophyta)	Chordata (Chordates)
Class	Chrysophyceae (Chrysophyceae)	Mammalia (Mammals)
Order	Chromulinales (Chromulinales)	Didelphimorphia (Didelphimorphia)
Family	Dinobryaceae	Didelphidae
Genus	Chrysococcus	Thylamys
Species	Chrysococcus bisetus	Thylamys pusillus

Conservation Status

NE — Not Evaluated

Common Fat-tailed Mouse Opossum

LC — Least Concern

Physical Characteristics

Attribute		Common Fat-tailed Mouse Opossum
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 Fat-tailed Mouse Opossum

Habitat

Typically found in diverse terrestrial and aquatic ecosystems.

Chrysococcus bisetus is a species of unicellular chrysophyte microalga in the genus Chrysococcus, class Chrysophyceae, order Chromulinales. The genus Chrysococcus is characterized by cells enclosed within a lorica — a secreted outer case or vesicle — through which flagella protrude, a structure that distinguishes it from many other chrysophytes. The epithet bisetus, meaning two-bristled, describes a diagnostic feature of the lorica, which bears two bristle-like projections used for species identification. Chrysococcus species inhabit freshwater and brackish environments, typically occurring in cool, nutrient-poor to moderately enriched lakes, ponds, and slow-flowing water bodies. C. bisetus has been recorded from Norwegian and Swedish waters, consistent with the historical focus of chrysophyte research in Scandinavian freshwater habitats, and also from Brazilian waters, suggesting a broader distribution. Chrysophytes including Chrysococcus species are important components of oligotrophic lake phytoplankton, where they contribute to primary production and serve as food for zooplankton. The golden-brown coloration of Chrysococcus arises from chlorophylls a and c together with fucoxanthin, pigments shared with other heterokonts. Unlike diatoms, chrysophytes produce chrysolaminarin as their storage carbohydrate rather than starch. C. bisetus has not been assessed under IUCN criteria and is listed as Not Evaluated. As with most freshwater microalgae, global population size and distribution are poorly characterized, limiting meaningful conservation assessment.

Common Fat-tailed Mouse Opossum

The Common Fat-tailed Mouse Opossum (<em>Thylamys pusillus</em>) is a small marsupial belonging to the genus Thylamys within the family Didelphidae. Like other members of its genus, this species typically stores fat in its tail, which becomes swollen during periods of food abundance and is metabolised during leaner times, a physiological adaptation that provides energy reserves. <em>Thylamys pusillus</em> is generally found in diverse terrestrial and aquatic ecosystems, often in dry woodlands, scrublands, and grassland habitats of South America. The species is assessed as Least Concern on the IUCN Red List, indicating it is not currently considered at risk of extinction. Detailed geographic range data are not available in the current record, but members of this genus are typically distributed across parts of Argentina, Bolivia, Paraguay, and Uruguay. Biological traits including average lifespan, body dimensions, and specific dietary composition remain poorly documented in the scientific literature, though Thylamys species are generally considered omnivorous, often consuming insects, small vertebrates, and plant material.