Rajiformes

Rajiformes, commonly known as rays, are an order of cartilaginous fishes that belong to the subclass Elasmobranchii. They are characterized by their flattened bodies, pectoral fins that are fused to their heads, and gill slits located on the ventral side of their bodies. Rays are a diverse group of fish, with over 500 species found in all oceans of the world, from shallow coastal waters to the deep sea.

Warrah skate – Dipturus lamillai

Short tail Yellownose skate – Dipturus brevicaudatus

Yellownose skate – Dipturus chilensis

Thornback ray – Raja clavata

Small-eyed ray – Raja microocellata

Undulate ray – Raja undulata

Rough ray – Raja radula

Speckled ray – Raja polystigma

Mediterranean starry ray – Raja asterias

Blonde ray – Raja brachyura

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Common Names

The term "rays" is the most common name for this order, though specific types of rays often have their own common names. Some examples include:

  • Stingrays
  • Skates
  • Sawfish
  • Electric rays
  • Manta rays

Characteristics

The most defining characteristic of Rajiformes is their flattened bodies, which are dorsoventrally compressed. This adaptation allows them to live on the seafloor and ambush their prey. Other common features include:

  • Pectoral Fins: Fused to the head, forming wing-like structures for swimming and maneuvering.
  • Gill Slits: Located on the underside of the body, allowing them to breathe while lying on the bottom.
  • Spiracles: Openings on top of the head that draw in water for respiration.
  • Mouth: Situated on the underside of the head.
  • Five Gill Slits: Common to all Elasmobranchii, allowing them to breathe.

Some species also have unique characteristics, such as the venomous spines of stingrays and the saw-like snout of sawfish.

Environments

Rays inhabit a wide range of marine environments, including:

  • Shallow coastal waters: This is where many species, like stingrays, can be found.
  • Deep sea: Some species, like the deep-sea skate, live at depths exceeding 2,000 meters.
  • Coral reefs: Many species are associated with coral reefs, using them for shelter and food.
  • Open ocean: The largest rays, like manta rays, live in the open ocean.

References

For further information, consult these reliable resources: