Male cartilaginous fishes transfer sperm using claspers, modified inner edges of the pelvic fins. Male chimaeras have those, plus two extras: a pair of small prepelvic claspers in pockets ahead of the pelvic fins, and a frontal clasper, or tenaculum, mounted on the forehead.
The tenaculum is a stalked, denticle-armed club that retracts into a depression between the eyes when not in use. Observations and anatomy indicate it is used to hold the female, most plausibly by gripping the leading edge of her pectoral fin during copulation. Nothing comparable exists in sharks or rays.
The spotted ratfish also carries a defensive weapon: a stout, venom-associated spine at the front of the first dorsal fin, capable of inflicting a painful wound. It is a defence against predators, and a reason the fish is handled carefully when brought aboard.