Dalatiidae

Dalatiidae is a family of sharks belonging to the order Squaliformes. They are commonly known as sleeper sharks, gulper sharks, cookie-cutter sharks, or bramble sharks. This family comprises six genera and approximately 12 species. These sharks are found in deep waters worldwide, typically inhabiting the mesopelagic and bathypelagic zones, ranging from 200 to 3,000 meters (660 to 9,800 feet) deep.

Cookie cutter shark – Isistius brasiliensis

Characteristics

Dalatiidae sharks exhibit several distinguishing features. They possess a slender, eel-like body shape, which aids in maneuvering through the deep ocean. Their bodies are typically covered in rough, sandpaper-like dermal denticles, giving them a distinctive texture. They have large, prominent eyes adapted for low light conditions, and their jaws are equipped with rows of sharp, pointed teeth. Most Dalatiidae sharks have bioluminescent organs, called photophores, located on their undersides, allowing them to blend in with the dim light of the deep ocean.

Environment

Dalatiidae sharks are highly adapted to their deep-sea environment. They possess a slow metabolism and can survive on minimal food, relying on a variety of prey, including fish, cephalopods, and other sharks. Some species are known for their unique feeding strategies, such as the cookie-cutter shark, which uses its sharp teeth to take circular bites out of larger animals.

Genera and Species

The Dalatiidae family includes the following genera and species:

  • Dalatias
    • Dalatias licha (Common sleeper shark)
  • Isistius (Cookie-cutter sharks)
    • Isistius brasiliensis (Brasilian cookie-cutter shark)
    • Isistius pluto (Smalltooth cookie-cutter shark)
  • Euprotomicrus
    • Euprotomicrus bispinatus (Bramble shark)
  • Somniosus (Sleeper sharks)
    • Somniosus microcephalus (Greenland shark)
    • Somniosus pacificus (Pacific sleeper shark)
    • Somniosus longus (Longnose sleeper shark)
    • Somniosus antarcticus (Antarctic sleeper shark)
    • Somniosus scotius (Scotian sleeper shark)
  • Centroscymnus
    • Centroscymnus owstoni (Black dogfish)
    • Centroscymnus coelolepis (Korean sleeper shark)
    • Centroscymnus crepidater (Scalloped dogfish)
    • Centroscymnus macracanthus (Big-spine dogfish)
    • Centroscymnus ritteri (Ritter's dogfish)
  • Scymnodon
    • Scymnodon ringens (Gulper shark)

References

For more information on Dalatiidae sharks, you can refer to the following reliable sources: