Chimaeras are cartilaginous fish in the order Chimaeriformes, known informally as ghost sharks, rat fish, spookfish, or rabbit fish.
At one time a "diverse and abundant" group (based on the fossil record), their closest living relatives are sharks and rays, though their last common ancestor with them lived nearly 400 million years ago. Today, they are largely confined to deep water.
They have elongated, soft bodies, with a bulky head and a single gill-opening.
Their skin is smooth and naked, lacking placoid scales (except in the claspers), and their color can range from black to brownish gray.
For defense, most chimaeras have a venomous spine in front of the dorsal fin.
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At one time a "diverse and abundant" group (based on the fossil record), their closest living relatives are sharks and rays, though their last common ancestor with them lived nearly 400 million years ago. Today, they are largely confined to deep water.
They have elongated, soft bodies, with a bulky head and a single gill-opening.
Their skin is smooth and naked, lacking placoid scales (except in the claspers), and their color can range from black to brownish gray.
For defense, most chimaeras have a venomous spine in front of the dorsal fin.
Continued...
Source