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 2,535–2,630 m (8,317–8,629 ft) 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 mm × 74.8 mm (4.84 in × 2.94 in).

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