Cynarina  (Cynarina lacrymalis)

This species is classified as Near Threatened (NT) on the IUCN Red List (1) and listed on Appendix II of CITES (2).

With its cylindrical-shaped, thick, fleshy polyp and radiating tentacles, the distinctive Cynarina lacrymalis is a highly conspicuous coral within the reef environment (3) (4). Thick septa project inwards from the polyp wall, and are surrounded by large, rounded or lobed teeth-like projections (3). During the day, the translucent wall surrounding the sac-like body cavity may inflate with water, swelling to twice its normal size during periods of low light, greatly increasing the surface area of the body and the photosynthesising zooxanthellae exposed to the sunlight (3) (4). Cynarina lacrymalis is a solitary coral that is most often attached to the sea bed, although it may also be free-living (4). It is typically a mixture of green or brown in colour, but may also be pink, and sometimes other colours. This unique coral is the sole member of the Cynarina genus (3).

Cynarina lacrymalis is found in the Indian and western Pacific oceans, the Red Sea and the Gulf of Aden (1).

Cynarina lacrymalis occurs in protected reef environments with a deep sandy substrate, down to depths of 50 metres (1) (3).

Like many coral species, Cynarina lacrymalis is zooxanthellate, which means that its tissues contain large numbers of single-celled algae called zooxanthellae. The coral and the algae have a symbiotic relationship in which the algae gain a safe, stable environment within the coral's tissues, while the coral receives nutrients produced by the algae through photosynthesis. By harnessing the sun's energy in this way, corals are able to grow rapidly and form vast reef structures, but are constrained to live near the water surface. While, on average, zooxanthellate coral can obtain around 70 percent of its nutrient requirements from zooxanthellae photosynthesis, the coral may also feed on zooplankton (3). 

With an estimated 20 percent of the world’s coral reefs already destroyed, Cynarina lacrymalis faces many threats that are affecting coral reefs globally (5) (6). Worldwide there is increasing pressure on coastal resources resulting from human population growth and technological development. Consequently, there has been a significant increase in domestic and agricultural waste in the oceans, poor land-use practices that result in an increase in sediment running on to the reefs, and over-fishing, which can have ‘knock-on’ effects on the reef (5). However, the major threat to corals is global climate change, with the expected rise in ocean temperatures increasing the risk of coral ‘bleaching’, in which the stressed coral expels its zooxanthellae, often resulting in the death of the coral. Climate change may also lead to more frequent, severe storms, which can damage reefs, and rising carbon dioxide levels may make the ocean increasingly acidic. Such stresses can also make corals more susceptible to disease, parasites and predators, such as the crown-of-thorns sea star (Acanthaster planci) (5) (6) (7).

In addition to being listed on Appendix II of the Convention on International Trade in Endangered Species (CITES), which makes it an offence to trade this species without a permit, Cynarina lacrymalis also forms part of the reef community in numerous marine protected areas. To specifically conserve this coral, recommendations have been made for a raft of studies into various aspects of its biology, population status, habitat and threats to its survival (1).

ARKive is supported by OTEP, a joint programme of funding from the UK FCO and DFID which provides support to address priority environmental issues in the Overseas Territories, and Defra

For further information on the conservation of coral reefs, see:

• Reef Check:
  http://www.reefcheck.org/
• Coral Reef Alliance:
  http://www.coral.org/