© The BlowfishIf sharks are the film stars of the ocean, and rays the supermodels, then the chimaeras are the camera operators. Cousins of both sharks and rays, yet more ancient and unique than either, chimaeras are often overlooked members of the cartilaginous fishes. And yet, without them, the ocean would be a much poorer place.

Also known as ghostsharks or ratfish, chimaeras share many of the classic characteristics of their famous sharky brethren, but also have a few bony fish features too. Lacking sharks’ conveyer belt of replaceable teeth, chimaeras instead favour crushing bony plates, and having a gill plate as opposed to visible gill slits are just a few differences.

They still have that amazing skeleton made from cartilage and, like sharks, possess those marvellous electroreceptive cells dotted all over their heads. Lacking the fearsome teeth of the larger predatory sharks could put the chimaeras squarely on the menu, but thanks to a sharp venomous spine in front of the dorsal fin, these ghostsharks don’t let anything bother them.

The largest chimaeras can grow to 1.5m in length, with the smallest coming in around the 40cm mark. They often have large eyes and some, such as the Elephant Shark, have strange extensions on their nose which they use to shovel through the sand on the hunt for its dinner. Although occasionally found in shallow waters, most ratfish make their home in the extreme darkness of the deep-sea. Chimaeras are often spotted by deep-sea submersibles, and have been recorded in the inky blackness over 3,000m down.

Appearing 450 million years ago…before even trees evolved...chimaeras really ARE the granddaddies of the ocean, yet we know so very little about them. As exploration and exploitation of the deepsea continues, we have to be careful not to forget about the ghostsharks, in case they disappear into the gloom forever.