Chimaeras are sharks much cooler cousins. They are not sharks, i.e. elasmobranchs, but rather a whole other subclass, Holocephali, that split from sharks nearly 400 mya. They are primarily deep water ...

Worldwide, these animals spend most of their time at depths between 400-2,000 meters deep, with some species coming to shallower depths (as little as 3 meters) to mate and lay eggs.

Strikingly, Holocephali (chimaeras), dipnoids (lungfish) and monotremes ... We also find that in gastric species the pepsinogen gene complement varies significantly ...

Freshwater species contain only about 1 per cent of urea. ... elasmobranchs, including the Holocephali, contain 2–2.5 per cent of urea in their blood and tissues.

Holocephali.” The amended ordinance states it is now illegal not only to fish, possess or sell of any shark species, but also to possess or trade any shark meat or organs.

In his 1859 book On the Origin of Species, ... It’s a related type of cartilaginous fish known as a “chimaera” and belongs to a subclass called Holocephali which diverged from the shark ...