Chordata · chordates

Cookiecutter shark

Isistius brasiliensis

Dalatiidae · kitefin sharksIUCN: Least Concern
Cookiecutter shark
Photo: NOAA Observer Project · Public domain · Wikimedia Commons · resized

A small, glowing shark that scoops round plugs of flesh from whales and tuna.

Fun factIt has bitten submarine sonar domes.

Waters
Worldwide
Depth zone
Twilight zone, 200–1,000 m, Open-ocean surface waters
Diet
Bites of flesh from larger animals
Size
Up to 50 cm

Classification

Chordata › Chondrichthyes › Squaliformes › Dalatiidae

  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. Clade Selachii sharks
    • Sharks: gill slits on the sides of the head
    • Pectoral fins not joined to the head
  10. Superorder Squalomorphii squalomorph sharks
    • Most have no anal fin; cow and frilled sharks are the exception
    • Includes dogfish, sleeper, and angel sharks
  11. Order Squaliformes dogfish sharks
    • Dogfish sharks: no anal fin
    • Many have spines before the dorsal fins; some glow (bioluminescence)
  12. Family Dalatiidae kitefin sharks
    • Kitefin sharks, including the cookiecutter that bites plugs from larger animals
  13. Genus Isistius
    • Species in the same genus are very close relatives and often look alike.
  14. Species Isistius brasiliensis Cookiecutter shark

Closest relatives in the guide