Cimar Round Ray vs Common Water Rat

Urotrygon cimar compared with Hydromys chrysogaster

Key Differences

• Cimar Round Ray is Near Threatened while Common Water Rat is Least Concern.

Taxonomic Classification

Rank	Cimar Round Ray	Common Water Rat
Kingdom same	Animalia (Animals)	Animalia (Animals)
Phylum same	Chordata (Chordates)	Chordata (Chordates)
Class	Elasmobranchii	Mammalia (Mammals)
Order	Myliobatiformes (Myliobatiformes)	Rodentia (Rodents)
Family	Urotrygonidae	Muridae (Mice & Rats)
Genus	Urotrygon	Hydromys
Species	Urotrygon cimar	Hydromys chrysogaster

Evolutionary Relationship

Cimar Round Ray and Common Water Rat share a common ancestor at the Phylum level: Chordata. (Chordates)

Conservation Status

Cimar Round Ray

NT — Near Threatened

Common Water Rat

LC — Least Concern

Physical Characteristics

Attribute	Cimar Round Ray	Common Water Rat
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Cimar Round Ray

Common Water Rat

Habitat

Typically found in diverse terrestrial and aquatic ecosystems.

Cimar Round Ray

The Cimar round ray (Urotrygon cimar) is a small stingray in the family Urotrygonidae, found in the eastern Pacific Ocean along the coasts of Central America and northern South America, including the waters of Costa Rica, Panama, Colombia, and Ecuador. It inhabits shallow coastal and estuarine waters over sandy and muddy bottoms, typically at depths of less than 50 meters, where it feeds on small benthic invertebrates and fish. Like other round rays in the genus Urotrygon, it has a nearly circular disc outline, a relatively slender tail, and a venomous caudal spine used defensively against predators. The species is classified as Near Threatened by the IUCN, reflecting its restricted range, vulnerability to coastal habitat degradation, and incidental capture in artisanal and commercial fisheries throughout its range. Bycatch in shrimp trawls and gill nets represents a significant ongoing threat to Urotrygon species throughout the eastern Pacific. Shallow coastal habitats in Central America and Colombia face continued pressure from development, mangrove loss, and pollution. The species' reproductive biology, like that of most Urotrygon rays, involves ovoviviparity, with females giving birth to live young after internal development. Population assessments for this species remain limited, and more data on abundance and mortality rates are needed.

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.