Cyanagraea

Cyanagraea praedator is a species of crab that lives on hydrothermal vents, and the only species in the genus Cyanagraea.

It is found at depths of 2535 - 2630 m on the East Pacific Rise, where it lives "in the upper part of black smoker chimneys". Its haemocyanin has a strong affinity for oxygen, and displays a significant Bohr effect, which is unaffected by lactic acid.

Cyanagraea praedator is "by far the largest" species in the family Bythograeidae, growing to a maximum carapace size of 123.0 x.

The leech Bathybdella sawyeri has been observed attached to C. praedator.