Common Fat-tailed Mouse Opossum vs Common ray

Thylamys pusillus compared with Telatrygon biasa

Key Differences

• Common Fat-tailed Mouse Opossum is Least Concern while Common ray is Vulnerable.

Taxonomic Classification

Rank	Common Fat-tailed Mouse Opossum	Common ray
Kingdom same	Animalia (Animals)	Animalia (Animals)
Phylum same	Chordata (Chordates)	Chordata (Chordates)
Class	Mammalia (Mammals)	Elasmobranchii
Order	Didelphimorphia (Didelphimorphia)	Myliobatiformes (Myliobatiformes)
Family	Didelphidae	Dasyatidae
Genus	Thylamys	Telatrygon
Species	Thylamys pusillus	Telatrygon biasa

Evolutionary Relationship

Common Fat-tailed Mouse Opossum and Common ray share a common ancestor at the Phylum level: Chordata. (Chordates)

Conservation Status

Common Fat-tailed Mouse Opossum

LC — Least Concern

Common ray

VU — Vulnerable

Physical Characteristics

Attribute	Common Fat-tailed Mouse Opossum	Common ray
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Common Fat-tailed Mouse Opossum

Habitat

Typically found in diverse terrestrial and aquatic ecosystems.

Common ray

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.

Common ray

<em>Telatrygon biasa</em>, the common ray, is a cartilaginous fish in the family Dasyatidae, order Myliobatiformes, belonging to the broader class Chondrichthyes. The species is assessed as Vulnerable on the IUCN Red List, indicating elevated concern over population viability. Common rays are demersal elasmobranchs typically found in shallow coastal and inshore marine habitats, resting on sandy or muddy substrates. Like other dasyatid stingrays, <em>Telatrygon biasa</em> typically feeds on benthic invertebrates including crustaceans, mollusks, and worms, which it detects using electroreceptive ampullae of Lorenzini. It typically moves by undulating its broad pectoral disc, a hallmark locomotion style of stingrays. The vulnerable status of this species likely reflects pressures from bycatch in coastal fisheries and habitat degradation, which are common threats for inshore ray species across the Indo-Pacific region. Biological traits such as lifespan, precise body measurements, and detailed diet composition remain poorly documented for this taxon, and further field research is needed to characterize population structure and reproductive ecology. Conservation measures targeting bycatch reduction in artisanal and commercial fisheries would benefit this species.