Defining Features[edit | edit source]
Rajiformes are distinguished by their greatly enlarged pectoral fins, the fins go up to the side of their head. Rajiformes generally has a flattened body with their eyes located on the upper surface of the head and gills silts are on the underside of the body. The massive pectoral fin feature on Rajiformes makes it possible for them to swim by means of oscillating their pectoral fins. The pectoral fin is mainly supported by the cranium, and posteriorly by the trunk. They often have thornlike spines in a row along the midline of the back. They have up to two dorsal fins, and they have a small and weak caudal fin on their thin, whip-like tail. They have no anal fin, and have large pectoral fins that are fused to the rostrum.
Habitat and Range[edit | edit source]
Rajiformes are found in marine environments worldwide from the shoreline to about 3000m and (9842ft) and in tropical freshwaters as well. The greatest diversity is found in the tropical Indo-West Pacific regions, which includes the tropical waters from east coast of Africa to the east coast of Australia and Japan. However, Rajiformes are almost entirely absent from the coral islands of central & western Pacific. Most rays and skates are benthic in their marine habitats, the more sharklike forms (ex:sawfishes, guitarfishes) rest on the bottom. The more depressed forms (ex: electric rays, stingrays) rest and swim close to the bottom and often bury themselves in the bottom.
Fisheries Conservation and Concern[edit | edit source]
Rajiformes have been exploited by artisanal fisheries and other small scale fisheries in developing countries, but has yet to become the target of large scale fisheries. However, Rajiformes have been heavily impacted by humans in recent centuries, shown by the slow growth rates and low reproductive potentials, which means they are vulnerable to even modest exploitation. Fisheries directed at bony fishes could potentially pose a negative impact on the skates and rays before they overexploit the target bony fishes.
Closest Relatives[edit | edit source]
[Myliobatiformes + Rhinopristiformes] + Torpediniformes
Example Species in Rajiformes[edit | edit source]
Spreadfin Skate[edit | edit source]
Defining Features: The rostrum is pointed like a triangle, and the pectoral fins are triangular as well with the front edge being slightly concave and the tail edge slightly convex. They have a thin tail with thorns on it, and very few thorns on its pectoral fins. It is the only skate to lack thorns on the area posterior to the spiracles. The top of the skate is dark brown, while the bottom is black.
Range & Habitat: The Spreadfin skate lives in Neritic and Deep Benthic zones between 55 meters and 384 meters, and its range is in the northern Gulf of Mexico from Florida to Texas.
IUCN Concern: The Spreadfin skate is classified as Data Deficient. It is caught and harvested, and bycatch may also be a threat towards populations as they live close to coastlines.
Clearnose Skate[edit | edit source]
Rostroraja eglanteria[edit | edit source]
*formerly known as Raja eglanteria
Defining Features: The areas next to its rostrum ridge are translucent, which is where its name was derived from. The tail is thin and the rostrum is pointed and the body is shaped like a diamond. The clearnose skate is a dark brown or gray color, and it has an irregular pattern of darker spots or bars. The spine on its dorsal side is lined with thorns which offer protection to the skate.
Range & Habitat: The clearnose skate inhabits the Neritic zone at depths of up to 330 meters. They range in the Northwestern and Western Atlantic, from Massachusetts through the Mexican coast in the Gulf of Mexico.
IUCN Concern: The Clearnose skate is classified as Least Concern. It is caught and harvested, and bycatch may also be a threat towards populations as they live close to coastlines.
Example Species in the Gulf of Maine[edit | edit source]
Thorny Skate[edit | edit source]
Amblyraja radiata[edit | edit source]
Defining Features: The species is named after the thorns which line their spine, tail, and edges of pectoral fins. There are also smaller spines which fill the spaces on the rest of their body. Skates do not have venomous spines that rays have, so its thorns are relatively harmless to humans. It has rounded pectoral fins and rostrum, and a stout tail.
Range & Habitat: The thorny skate inhabits the Deep Benthic Zone at a minimum depth of 18 meters and a maximum depth of 1,400 meters. The Thorny skate lives in the Northwestern Atlantic Ocean near the coast. They are found in the East Coast of North America to the Hudson Bay, the coasts of Greenland and Iceland, and the coasts of Norway and the British Isles.
The Thorny skate classified as Vulnerable. It is caught and harvested, and bycatch may also be a threat towards populations as they live close to coastlines.
References[edit | edit source]
Chondrichthyan Tree of Life: https://www.sharksrays.org
Grzimek's Animal Life Encyclopedia: https://www.encyclopedia.com/environment/encyclopedias-almanacs-transcripts-and-maps/rajiformes-skates-and-rays.
Clear nose skate: https://www.iucnredlist.org/species/161658/5474334
Thorny skate: https://www.iucnredlist.org/species/161542/5447511
Spreadfin Skate: https://www.iucnredlist.org/species/161718/5487815
Florida Museum Thorny Skate: https://www.floridamuseum.ufl.edu/discover-fish/species-profiles/amblyraja-radiata/
Florida Museum Clearnose Skate: https://www.floridamuseum.ufl.edu/discover-fish/species-profiles/raja-eglanteria/
Florida Museum Spreadfin Skate: https://www.floridamuseum.ufl.edu/discover-fish/species-profiles/dipturus-olseni/