Triactis
| Triactis producta | |
|---|---|
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| Lybia edmondsoni with Triactis producta on the claws | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Cnidaria |
| Class: | Anthozoa |
| Subclass: | Hexacorallia |
| Order: | Actiniaria |
| Family: | Aliciidae |
| Genus: |
Triactis Klunzinger, 1877 |
| Species: | T. producta |
| Binomial name | |
|
Triactis producta Johnson, 1861 |
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| Synonyms | |
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Triactis is a genus of sea anemone in the family Aliciidae. It is monotypic, having only one species – Triactis producta. This is found in shallow waters in the Indo-Pacific where it lives on the seabed, rocks and corals. It derives much of its energy needs from the symbiotic algae it contains. It also forms a mutualistic relationship with small Lybia crabs.
Triactis producta is a small, cryptic, pale brown sea anemone. The base grows to about 1 cm (0.4 in) in diameter and the column tapers slightly and extends to about 1.5 cm (0.6 in) in height. It is topped by a crown of about 50, relatively long tentacles. Halfway up the column there is a ring of branching, pale brown pseudo-tentacles. These are tubular extensions of the wall of the column and on their upper side there are a few semi-spherical bulges known as vesicles. These can be grey, pink or green and are packed with stinging cells called cnidocytes.
Triactis producta is found in shallow waters of the tropical Indo-Pacific Ocean, its range extending from the Red Sea and Mozambique to Hawaii and French Polynesia. It is inconspicuous, often growing in crevices and concealed among the branches of stony corals. It often occurs in dense clusters of what are probably cloned individuals.
Triactis producta has two ways of feeding. In the daytime, when the light is bright, it retracts its tentacles and extends its pseudo-tentacles. These are dark brown because of the dense concentration of symbiotic algae known as zooxanthellae that they contain. These produce sugars by photosynthesis in sunlight which the anemone uses as nourishment. Retracting its tentacles maximises the photosynthetic potential of the anemone. The well-armed vesicles protect the pseudo-tentacles which may appear edible to a potential predator. At night, or when the animal is in a dim light, the crown of tentacles expands and the tentacles search for small invertebrates in the surrounding water, immobilising them with their cnidocytes.
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Wikipedia