Dive deep deep down into the ocean, long past the point where the sun’s rays can penetrate, and you will enter the realm of the ghost sharks.

Also called chimaeras, ghost sharks are dead-eyed, wing-finned fish rarely seen by people.

Relatives of sharks and rays, these deep-sea denizens split off from these other groups some 300 million years ago. Even though ghost sharks have been gliding through the depths since long before the dinosaurs, we still know very little about them. Now, video recently released by the Monterey Bay Aquarium Research Institute in California has shined new light on these mysterious creatures.

In 2009, the institute sent a remotely operated vehicle, or ROV, on several dives to depths of up