Also this summer we met one of the many “wanderers of the sea” that is one of those species such as tunicate jellyfish and ctenophores that let themselves be carried away by the currents, reducing their movements to a minimum.
We are talking about the Glass Ctenophore – Bolinopsis vitrea – which we have already filmed some time ago, this specimen seems quite old but as soon as touched it showed us the splendid reflections of bioluminescence that the ctenophores activate when they are stimulated.
Glass ctenophore belongs precisely to the philum of the Ctenophores which groups together transparent and gelatinous organisms, typically pelagic, whose body is crossed by ribs along which we notice a series of vibrant eyelashes. The eyelashes are arranged in a comb and from here derives the name which is equivalent to “comb bearers”.
In the tentacles or in the small combs, the cells are not stinging but adhesive, and it is precisely these adhesive cells called “colloblasts” which capture the zooplankton on which these organisms feed. The small combs mentioned above are also capable of producing particular iridescences. Their body, like jellyfish, is made almost entirely of water. Like coelenterates, the organs of digestion are contained in a large internal cavity and the mouth is located at the end of the body. The individuals are all hermaphrodites with simultaneous production of eggs and sperms.
Ctenophora comprises a phylum of invertebrate animals that live in marine waters around the world. They are known for the clumps of cilia they use to swim (commonly called “combs”) and are the largest animals to swim with the aid of cilia. Depending on the species, adult ctenophores range from a few millimeters to 1.5 m (4 ft 11 in). Only 100 to 150 species have been validated, and possibly another 25 have not been fully described and named.
They are cydiotids with egg-shaped bodies and a pair of retractable tentilla-trimmed tentacles (“little tentacles”) that are covered in colloblasts, sticky cells that capture prey. Their bodies consist of a gelatinous mass, with a layer of two thick cells on the outside and another lining the inside cavity. The phylum has a diverse range of body shapes, including egg-shaped cydippids with retractable tentacles that capture prey, generally flat platyctenids with no comb, and broad-mouthed beroids, which prey on other ctenophores.