|Origin||No Man's Sky|
|Species Type||Land Coral|
|Reproduction||Sexual; releasing gametes|
Hermaphroditic; polyp budding
|Average Height||Colony: 10-14 ft|
|Average Weight||Colony: 4,000 lbs|
|Locomotion||Sessile in adult form|
|Predators||None, though Barnaclebeaks sharpen their beaks on them|
|Capital City||Tinikoho Moor|
Cave Coral (Aprius ucrutersis) is a species of stony coral-equivalent indigenous to the Tinikoho Moor region of Ilongoqungo, primarily found around Tinikoho Moor, although also seen in various other biomes across the globe, as well. They are colonial organisms that form tall, stone structures that host a species of microscopic algae-equivalent to provide them with extra energy throughout the day.
Cave Coral are quite similar to their Earth-bound counterparts in both physical appearance and overall behavior. For much of their lives they are sessile organisms. Despite the appearance of being a large stony structure, it is in fact the colonial skeleton of thousands of tiny polyps. This skeleton is composed primarily of iron deposits and a natural concrete-like substance excreted by the polyps and their interconnecting coenosarc, providing an incredibly hard surface within which to live and some level of protection against the crystalline plutonium deposits that grow in the area. Within these structures, the polyps themselves sit within small cup-shaped depressions known as corallites.
The polyps are able to deform their own bodies to retract into their corallites, but can also rely on stingers equipped on the tips of their tentacles to strike at would-be predators. These organisms are so small this rarely effects larger sapient species, and give the polyps a sandpapery feel to them when an exposed hand is ran across them. Unlike corals found on Earth, Cave Coral polyps have developed an impressive twenty-fold symmetry. Their mouth is formed as a horned beak similar to those seen in cephalopods, and is surrounded by their many tentacles. When not deformed and retracted, their tentacles are cylindrical and taper to a point, but are surrounded by a screw-like whorl of tiny, fleshy extensions known as pinnules. Cave Coral are nocturnal by nature, only emerging from their colony to feed in darkness to prevent dessication. As such, those found in caverns are more likely to be seen feeding at any hour of the day. Interestingly, these cavern-bound members of the species have less algae-equivalent symbionts than those at the surface, as they cannot support them as easily.
Polyps are interconnected by their coenosarc, which is a complex and well-developed system of gastrovascular canals that allow for the transfer of nutrients between individuals.
Cave Corals are strictly filter-feeders, feeding on aeroplankton that floats freely through the air. Despite being carnivorous, local Gek have not eradicated them like the other carnivores on the planet. They also may take small insectoid creatures when available, using their tentacle spines to subdue the creature and feeding on it for some days with their beaks. Their spines carry trace amounts of neurotoxin that rapidly subdue anything small that they can pierce. The tentacles are then used to move the prey to the beak if sufficient in size, or grooves in the beak will be used to periodically scrape off the tentacle filaments of microscopic organisms. Their digestive system is U-shaped, and any remains they cannot digest are simply regurgitated to get carried away by the winds.
The species has a mutualistic symbiosis with a species of microscopic algae-equivalents. Studies have shown that those in the Tinikoho Moor area harbor a different species of these floral organisms than those found in other areas. These algae are given protection within the coral's skeletal shell and extract some of their host's waste chemicals for their own processes, while providing them with energy extracted via photosynthesis, and may actually aid in their calcification process. Generally speaking, a shocking 22% of the organic material within a colony may be algae.
In terms of extreme stress, Cave Corals can violently eject their algae symbionts in a process known as a "green misting". These green mistings are so powerful that they can be heard from up to 20 yards away and can be physically felt as a light "shock wave". This ultimately kills the algae as it cannot survive the toxins of the local atmosphere unabated but may save the coral colony itself. However, Atlas sentinels usually keep these corals in check to make sure this balance is not disturbed and as such this event is a rare occurrence to witness in the modern age.
Recent studies have shown some genetic link may exist between it and the Chlorolomba found on the planet Vuunega. This is an interesting find, as Vuunega and Ilongoqungo are in different galaxies yet this seems to indicate that the Aurix may have visited the planet in the past.
Cave Coral is both unisexual and hermaphroditic, and each is able to reproduce both sexually as well as asexually. This allows them to settle into new areas.
Predominately, a Cave Coral will reproduce sexually. Each colony has clusters of genders, based upon the areas where each original colonial member started and branching out. At the windiest times of the year, each of these genders will release clouds of gametes in tandem. Minimal environmental cues are necessary, but consist of the strength of the wind, time of the day, and the levels of ambient toxins and radiation in the air. When these match ideal conditions, all coral in the given area will release their material, which will fuse mid-air and form zygotes that quickly develop into new, temporarily mobile polyps known as paratropos, a planula-like larval stage that is elliptical in shape and has developed a parachute-like bell that helps carry them across the globe. Several hundred thousand of these polyps will be produced by each colony every year, although very few seem to make it to maturity. Considering the lack of predatory species on the planet, it is likely they mostly die off due to toxicity in a given area or not landing in an area with significant enough amounts of iron deposits in the soil.
These Paratropos are also attracted towards existing colonies should they find themselves landing near one, and will steer themselves to one as best they can to begin another branch of a colony. Although they have little say in their trajectory or landing path are are really mostly at the whim of the winds, those that land on existing colonies have a far better chance of survival than those that are forced to start colonies anew.
An interesting aspect of Cave Coral sexual broadcasting is that should different species cast their gametes on the same night, these can fuse together to form hybridized species, thus creating a very easy path of evolution for the group.
The Paratropo planulae exhibit chemosensitivity, and will try to move away from more heavily toxified areas; they appear to avoid radioactive areas as well if at all possible unless they sense an existing colony in the area, again by sensing the chemicals such colonies will exude. They do not enjoy lighted areas and will also try to steer to shadier spots, which often will be caverns. They are not always successful given their weak control over their movement. High failure rates are common throughout these motile cycles, and only a few will live long enough to join an existing or start a new colony. During this time, they will evolve from parachute-equipped paratropos, into a polyp, and finally into a truly mature coral head. This process usually only takes a day or two, but sometimes they can accidentally enter the air stream. Those that do have been known to become trapped here for a few months. On rare occasions individuals have been recorded as being stuck in the air stream for as long as ten years.
As a new polyp grows into a coral head, it takes on the ability to reproduce via budding. This is done to replace deceased colonial members or when excess energy allows for the process. The parent coral will split longitudinally (down the middle) and each half will grow farther and farther apart until they are completely separated; this involves a division of its body, known as the coelenteron, starting with the mouth and tentacles and separating down the rest of the body. This usually takes a week or two to complete. It allows for a high reproductive and success rate.