Spanish Dancer (31Jan10).jpg
Kenting, Taiwan -- The nudibranch Hexabranchus sanguineus, aka 'Spanish dancer'.
Hexabranchidae feed on sponges. When disturbed, they may display a flashing behavior by suddenly exposing brightly colored areas of the dorsum, which are normally covered by folds of the mantle margin. This can be accompanied by vigorous swimming escaping behavior.
Hexabranchus sanguineus can propel itself through the water by unfurling its mantle margin and performing an undulating movement. The animal was thus given the common name 'Spanish dancer' because the whirling swimming movement, and the red color of the mantle, are reminiscent of the skirt movements of a flamenco dancer.
This species of very large, strong-swimming nudibranch is one of the largest of all nudibranchs: specimens of up to 60 cm in length have been reported! At about 20-25 cm, the specimen in the picture is considerably smaller however.
The Emperor shrimp, Periclimenes imperator, is a commensal that is commonly found living on Hexabranchus sanguineus.