Lace Coral

Appearance

Lace corals form ornate tree-like structures, with all the flattened, blunt-ended branches growing in one plane. These fan-like corals are remarkable for their bright colours, including violet, red, pink, orange, and yellow, and grow up to 25 cm tall. The colour is deposited within the limestone skeleton and remains even after the animal tissue is gone, unlike reef-building corals which have white skeletons and the only colour is found in the living tissue

Distribution

Indo-West Pacific Ocean: Red Sea to the Galapagos Islands.

Status

Distichopora violacea is listed on Appendix II of CITES.

Habitat

Unlike many coral species, lace corals do not have the symbiotic algae zooxanthellae living within the coral tissue; they are azooxanthellate. They are therefore not dependent on light and thus can live where the reef-building corals, dependent on photosynthetic algae, can not. I=They inhabit somewhat nutrient-rich caves and areas beneath overhangs where they develop flat-sided growths that face into the current.

Reproduction

Reproduction in lace corals is more complex than in reef-building corals. The polyps reproduce asexually, producing jellyfish-like medusae, which are released into the water from special cup-like structures known as ampullae. The medusae contain the reproductive organs, which release eggs and sperm into the water. Fertilised eggs develop into free-swimming larvae that will eventually settle on the substrate and form new colonies. Lace corals can also reproduce asexually by fragmentation.

Food

Lace corals are hydrozoans, and thus have different type of polyps with different functions than anthozoan corals. The polyps of hydrozoans are near microscopic size and are mostly imbedded in the skeleton, connected by a network of minute canals. All that is visible on the smooth surface are pores of two sizes; gastropores and dactylopores. The rows of gastropores flanked by one of two rows of dactylopores are diagnostic of the genus. Dactylopores house long fine hairs that protrude from the skeleton. The hairs possess clusters of stinging cells (nematocysts) that can inflict stings on human skin. These hairs capture prey, which is engulfed by gastrozooids, or feeding polyps, situated within the gastropores.