The combtooth dogfish, Centroscyllium nigrum, is a little-known deepwater dogfish

Squaliformes

Squaliformes is an order of sharks that includes about 97 species in seven families.Members of the order have two dorsal fins, which usually possess spines, no anal fin or nictitating membrane, and five gill slits. In most other respects, however, they are quite variable in form and size...

 shark

Shark

Sharks are a type of fish with a full cartilaginous skeleton and a highly streamlined body. The earliest known sharks date from more than 420 million years ago....

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Physical description

The combtooth dogfish has no anal fin, grooved dorsal spines, two dorsal fin

Dorsal fin

A dorsal fin is a fin located on the backs of various unrelated marine and freshwater vertebrates, including most fishes, marine mammals , and the ichthyosaurs...

s of about same size, pointed nose, large eyes, small gill

Gill

A gill is a respiratory organ found in many aquatic organisms that extracts dissolved oxygen from water, afterward excreting carbon dioxide. The gills of some species such as hermit crabs have adapted to allow respiration on land provided they are kept moist...

 slits, a short abdomen, short caudal peduncle, and is blackish-brown in color with white-tipped fins. It grows to a maximum of 50 cm.

Habits and Habitat

It is an uncommon deepwater shark found close to the bottom between 400 and 1,145 m.