vs Common Fat-tailed Mouse Opossum

Chrysococcus punctiformis 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 punctiformis	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 and South America, inhabiting ecosystems characteristic of the region.

Range

Distributed across Brazil, Norway, and Sweden.

Common Fat-tailed Mouse Opossum

Habitat

Typically found in diverse terrestrial and aquatic ecosystems.

Chrysococcus punctiformis is a unicellular freshwater chrysophyte microalga in the genus Chrysococcus, class Chrysophyceae. The specific epithet punctiformis — meaning point-shaped or dot-like — likely references the diminutive size of this species relative to other Chrysococcus species, or alternatively describes a distinctive punctate surface pattern on the lorica visible under microscopy. In Chrysococcus, the lorica is the primary taxonomic structure, and its form, texture, and any ornamentation distinguish species from one another. C. punctiformis has been recorded from Norwegian and Swedish freshwater environments, extending also to Brazilian localities. This broad distribution spanning subarctic Scandinavian lakes and tropical or subtropical South American water bodies suggests either genuine cosmopolitan dispersal of this species through passive mechanisms, or convergent morphological evolution that has been misidentified as the same taxon in different regions. Molecular phylogenetic data would help resolve this question. The species inhabits the limnetic zone of freshwater systems, where it functions as a primary producer and component of the nanoplankton community. Chrysococcus species are characteristic members of oligotrophic lake phytoplankton in Scandinavia, often co-occurring with other chrysophytes, diatoms, and chlorophytes. C. punctiformis uses chlorophylls a and c along with fucoxanthin for photosynthesis and may practice mixotrophic nutrition. It has not been assessed under IUCN criteria and is listed as Not Evaluated.

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.