This order is the most ancient one. It consists of 6 species (2 families and 4 genera). The most distinguishable feature is the possession of 6 or even 7 gill slits. This is considered a very primitive feature, as most modern sharks possess only 5 gill slits. Compared to sharks of other orders, frilled and cow sharks only have one dorsal fin.
These sharks have a widespread distribution and live preferably in deeper waters.
The knowledge about their biology is still fragmentary.
|© SeaPicsThe 7 gill slits of the |
broadnose sevengill shark
Typical species of the order of "Frilled and cow sharks":
Bluntnose sixgill shark