Chordata · chordates

Thorny skate

Amblyraja radiata

Rajidae · hardnose skatesIUCN: Vulnerable
Thorny skate
Photo: Ecomare/Oscar Bos · CC BY-SA 4.0 · Wikimedia Commons · resized

A cold-water skate of the Northwest Atlantic shelf, studded with thorny bucklers.

Fun factIts Gulf of Maine stock fell so low that keeping thorny skates has been banned in US waters since 2003.

Waters
Northeast US, Northwest Atlantic, Northeast Atlantic, Arctic Ocean
Depth zone
Continental shelf, Deep sea & continental slope
Diet
Crabs, shrimp, worms & fish
Size
Up to 1.1 m

Classification

Chordata › Chondrichthyes › Rajiformes › Rajidae

  1. Kingdom Animalia animals
    • Many-celled organisms that eat other living things for energy (heterotrophs)
    • Cells have no cell walls
    • Most can move at some stage of life
  2. Clade Bilateria bilateral animals
    • Body has a left and right side that mirror each other (bilateral symmetry)
    • Head end with concentrated nerves; three tissue layers
    • Includes about 99% of all living animal species
  3. Clade Deuterostomia deuterostomes
    • In the embryo, the first opening becomes the anus and the mouth forms second
    • Includes echinoderms and chordates
  4. Phylum Chordata chordates
    • At some stage of life: a stiffening rod along the back (notochord)
    • A hollow nerve cord along the back (dorsal)
    • Slits in the throat (pharyngeal slits) and a tail past the anus
  5. Subphylum Vertebrata vertebrates
    • A skull (cranium) protecting a brain
    • Backbone or similar support around the nerve cord
    • Includes fishes, amphibians, reptiles, birds, and mammals
  6. Infraphylum Gnathostomata jawed vertebrates
    • Jawed vertebrates: jaws formed from gill arches
    • Paired fins or limbs
    • Includes all fishes except hagfish and lampreys, plus all tetrapods
  7. Class Chondrichthyes cartilaginous fishes
    • Skeleton made of cartilage, not bone
    • Skin covered in tooth-like scales (denticles)
    • Teeth constantly replaced; males have claspers for mating
  8. Subclass Elasmobranchii sharks & rays
    • Sharks and rays: five to seven separate gill slits on each side
    • Many rows of replaceable teeth
  9. Superorder Batoidea rays & skates
    • Rays and skates: flattened bodies with gill slits underneath
    • Pectoral fins joined to the head
    • Many have crushing, pavement-like teeth
  10. Order Rajiformes skates
    • Skates: lay leathery egg cases ('mermaid's purses')
    • Many have rows of thorny bumps along the back and tail
  11. Family Rajidae hardnose skates
    • Hardnose skates with a stiff snout
  12. Genus Amblyraja
    • Species in the same genus are very close relatives and often look alike.
  13. Species Amblyraja radiata Thorny skate

Closest relatives in the guide