Coelacanth vs Common Fat-tailed Mouse Opossum

Latimeria chalumnae compared with Thylamys pusillus

Key Differences

• Coelacanth is Critically Endangered while Common Fat-tailed Mouse Opossum is Least Concern.

Taxonomic Classification

Rank	Coelacanth	Common Fat-tailed Mouse Opossum
Kingdom same	Animalia (Animals)	Animalia (Animals)
Phylum same	Chordata (Chordates)	Chordata (Chordates)
Class	Coelacanthi (Coelacanthi)	Mammalia (Mammals)
Order	Coelacanthiformes (Coelacanthiformes)	Didelphimorphia (Didelphimorphia)
Family	Latimeriidae	Didelphidae
Genus	Latimeria	Thylamys
Species	Latimeria chalumnae	Thylamys pusillus

Evolutionary Relationship

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

Conservation Status

Coelacanth

CR — Critically Endangered

Population: ~500

Trend: Decreasing ↓

Common Fat-tailed Mouse Opossum

LC — Least Concern

Physical Characteristics

Attribute	Coelacanth	Common Fat-tailed Mouse Opossum
Diet	Carnivore	—
Average Lifespan	100 years	—
Average Length	1.8 m	—
Average Weight	80.0 kg	—

Habitat & Geographic Range

Coelacanth

Habitat

Found across multiple habitat types including tropical and subtropical moist broadleaf forests, tropical and subtropical dry broadleaf forests, and tropical and subtropical grasslands and savannas, among 8 distinct biome types spanning the Australasia and Afrotropic and Indomalayan realms. Populations are also found in montane and highland environments at higher elevations.

Range

Distributed across Comoros, Indonesia, Mozambique, and South Africa. Currently classified as Critically Endangered on the IUCN Red List, this species faces significant conservation challenges across its range.

Common Fat-tailed Mouse Opossum

Habitat

Typically found in diverse terrestrial and aquatic ecosystems.

Coelacanth

A living fossil thought extinct for 65 million years until rediscovered off South Africa in 1938, coelacanths can reach 2 meters and 90 kg. They belong to an ancient lobe-finned lineage more closely related to tetrapods than to ray-finned fish, making them scientifically invaluable for understanding vertebrate evolution. Found in deep rocky reef habitats of the Indian Ocean, they are nocturnal and undergo internal fertilization, giving birth to fully formed live young. Critically Endangered.

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.