Zanobatidae
The Zanobatidae are a family of skates, commonly known as deepwater skates, that belong to the order Rajiformes. These cartilaginous fishes are found in deep-water environments throughout the world, particularly in the Atlantic, Pacific, and Indian Oceans. The family comprises 14 species spread across five genera, namely Zanobatus, Psammobatis, Springeria, Discopyge, and Raja.
Characteristics
Zanobatid skates share several distinctive characteristics that differentiate them from other skate families. They typically possess a flattened, diamond-shaped body with large pectoral fins that are fused to the head. Their eyes are located on the dorsal side of the head, while the mouth and gill slits are positioned on the ventral side. Like other skates, they have five pairs of gill slits and a pair of spiracles on the dorsal surface, which allow for respiration while resting on the seabed.
Zanobatidae have a distinctive feature: a pair of large, wing-like pectoral fins that extend beyond the head, giving them a distinctive, "winged" appearance. Their bodies are covered in small, rough dermal denticles. Most species also have a pair of small, pointed dorsal fins located near the tail, and a single, small anal fin. The tail is typically slender and whip-like, with a caudal fin at its tip.
Habitat and Distribution
Deepwater skates, as their name suggests, inhabit deep-water environments, primarily on the continental slopes and abyssal plains. They are typically found at depths ranging from 200 to 1,500 meters (660 to 4,920 feet). Some species, however, have been documented at depths exceeding 2,000 meters (6,560 feet).
Zanobatid skates are widely distributed across the globe. They are found in all major oceans, including the Atlantic, Pacific, and Indian Oceans. Their distribution is influenced by water temperature, salinity, and the availability of suitable prey.
Diet
Deepwater skates are opportunistic predators, feeding primarily on a variety of benthic invertebrates, including crustaceans, worms, mollusks, and other fishes. They use their sensitive electroreceptors, called ampullae of Lorenzini, to detect the bioelectric fields generated by their prey. Their mouths are equipped with rows of small, pointed teeth that are used for crushing and tearing prey.
Reproduction
Zanobatid skates are oviparous, meaning they lay eggs. These eggs are enclosed in leathery cases called "mermaid's purses", which are deposited on the seabed. The young skates develop within the egg cases and emerge as miniature versions of adults.