Urotrygonidae
Urotrygonidae is a family of stingrays, commonly known as round rays, that inhabit the tropical and subtropical waters of the eastern Pacific Ocean. These rays are characterized by their round or oval-shaped bodies, with a relatively short, stout tail that bears a single, serrated spine. The family Urotrygonidae includes 13 recognized species, divided into three genera: Urotrygon, Urobatis, and Psammotrygon.
Characteristics
Urotrygonids have a distinctive appearance that sets them apart from other stingrays. Their bodies are typically flat and circular or oval-shaped, with a short, stout tail. The most prominent feature is their single, serrated spine located on the dorsal surface of the tail, which they use for defense. They have small, widely spaced eyes and a small, ventral mouth. Their pectoral fins are large and rounded, extending around the head and forming a continuous disc. Unlike other stingray families, Urotrygonidae lack dorsal fins.
Environments
Urotrygonids are found in various marine habitats, including sandy bottoms, rocky reefs, and seagrass beds. They prefer shallow coastal waters, typically ranging from the intertidal zone to depths of about 100 meters (330 feet). These rays are primarily benthic, meaning they spend most of their time on the seabed. Their ability to bury themselves in sand provides them with camouflage and protection from predators.
Distribution
Urotrygonids are endemic to the eastern Pacific Ocean, extending from the Gulf of California in the north to Chile in the south. Their distribution coincides with the warm, subtropical waters that support their preferred habitats. The specific geographical range of each species varies, with some being more widely distributed than others.
Diet
Urotrygonids are carnivorous and opportunistic feeders. Their diet consists mainly of bottom-dwelling invertebrates, including crabs, shrimps, clams, and worms. They use their keen sense of smell and electroreceptors to locate prey buried in the sand. Their powerful jaws and sharp teeth allow them to crush and consume their food.
Reproduction
Urotrygonids reproduce viviparously, meaning they give birth to live young. Females bear one to six young at a time, which are nourished by a placenta-like structure during gestation. The gestation period for Urotrygonids is estimated to be between six and nine months. The newborn rays are born relatively developed, with a small but functional spine.
Conservation
The conservation status of Urotrygonids varies depending on the species. Some species are considered to be of Least Concern, while others are listed as Vulnerable or Endangered. Threats to Urotrygonids include overfishing, habitat degradation, and climate change. Conservation efforts include establishing marine protected areas and promoting sustainable fishing practices.