A modern scleractinian coral with a twocomponent calcite ...
· Until now, all of the ca. 1,800 known modern scleractinian coral species were thought to produce skeletons exclusively of aragonite. Asymbiotic Paraconotrochus antarcticus living in the Southern Ocean is the first example of an extant scleractinian that forms a twocomponent carbonate skeleton, with an inner structure made of highMg calcite and an outer structure composed of aragonite.