Giant Leatherback

The bonecorus grows byssus threads, much like its relative the globby boneflora. These threads allow it to stick to rocks, and thus resist being washed ashore. The stalk of its ancestor is reduced to a fused nub at its pointed end. Bonecoruses usually cover rocks either at a slanted angle or nearly horizontally, bringing to mind snake scales or roof tiles. Their tendency to densely cover rocks at the intertidal zone is reminescent of barnacles.

Its heart-shaped part has a skeleton made of calcium carbonate. A velvety layer of living, photosynthesizing tissue, the 'mantle', covers this interior shell. Its spore-branches are reduced to disks of reproductive cells at the base of pores in its mantle. Spores are produced within these pores. This trait of spore production makes the spores slightly more protected. Bonecoruses' spore development is longer than that of its ancestor, allowing the spores to reach larger sizes. (specifically, up to 4 mm) The mantle is covered in a waxy secretion that prevents the germination of spores on its surface. It essentially suffocates the spores by covering the spores to the extent they can no longer receive oxygen or nutrients. (The spore-pores do not have a waxy secretion, as it would get in the way of the individual's own reproduction)

Bonecoruses' threads are so strong that dead bonecoruses are often found clinging to the same rock they clung to when alive. When the spore-trapping secretion decays, other bonecorus spores are able to germinate on the dead bonecorus. The spore-trapping secretion decays faster than the mantle in general, so bonecoruses can germinate on dead individuals before those individuals appear definitely deceased.