Rajiformes

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Leucoraja erinacea

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Raja electric organ site

Rajiformes is an order of cartilaginous fish that primarily includes the species commonly known as skates and their relatives. This order is part of the larger class Chondrichthyes, which also includes sharks, rays, and chimaeras. Rajiformes are distinguished by their flattened bodies and large pectoral fins, which are fused to the head, giving them a distinctive ray-like appearance. These adaptations allow them to live on or near the ocean floor, where they often camouflage themselves to avoid predators and to ambush prey.

Characteristics

Rajiformes possess a number of unique anatomical features that suit their benthic lifestyle. Their bodies are dorsoventrally flattened, which helps in lying flat against the seabed. The pectoral fins of Rajiformes, which extend from the sides of the head along the body, are key to their locomotion, enabling them to glide through water or bury themselves in sediment. Unlike most fish, Rajiformes breathe by drawing water in through spiracles on top of their heads, rather than through their mouths, allowing them to breathe while buried in sand or mud.

Habitat and Distribution

Members of the Rajiformes order are found in oceans around the world, from tropical to polar regions. They inhabit a variety of marine environments, including shallow coastal waters, deep-sea floors, and everything in between. Some species are adapted to life in brackish or even freshwater environments.

Diet

The diet of Rajiformes varies among species but generally consists of small fish, crustaceans, mollusks, and other invertebrates. They are mostly bottom-feeders, using their snouts to detect and dig out prey from the sediment.

Reproduction

Rajiformes exhibit a variety of reproductive strategies, including oviparity (egg-laying) and ovoviviparity (where eggs develop and hatch inside the female's body). Skates, for example, lay distinctive egg cases often referred to as "mermaid's purses," which they attach to underwater structures.

Conservation

Many species within the Rajiformes order are facing threats from overfishing, habitat destruction, and climate change. Some species are caught incidentally as bycatch in fisheries targeting other species, while others are targeted for their meat, fins, or for use in traditional medicines. Conservation efforts are underway in various parts of the world to protect these species and their habitats, including the establishment of marine protected areas and restrictions on fishing practices.

Classification

The order Rajiformes is divided into several families, including but not limited to:

• Rajidae (true skates)
• Anacanthobatidae (smooth skates)
• Arhynchobatidae (softnose skates)

Each of these families encompasses a diverse range of species, adapted to various ecological niches within the marine environment.

See Also

• Chondrichthyes
• Elasmobranchii
• Marine conservation

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