In this episode of underwater relaxation, we would like to introduce you to this beautiful little Xmas creature that is dressed for the occasion. Primovula roseomaculata, also known as a Soft coral cowrie, Allied Cowrie, or False Cowrie, is a species of sea snail, a marine gastropod mollusc in the family Ovulidae.
Soft coral cowrie (Primovula roseomaculata)
Cowries are molluscs
Molluscs are a big and very diverse group of creatures consisting of animals as different as mussels and octopuses! Most colourful and strikingly patterned among the molluscs are the cowries. Their shells were used as currency in different cultures throughout history and are now prized collector items, due to their shining and often brightly coloured and patterned shell. However, what we as ocean enthusiasts see, is not the shell itself, but rather the soft mantle of the animal, wrapped around the shell. The mantle is even more beautiful than the shell itself, often bearing a striking resemblance to the soft coral that these cowries prey on, even including tentacle-like protrusions, to completely blend in with its coral host. These branching papillae on their mantle are not only there to complete the finishing touch on their extravagant camouflage, but assist in the respiration of the cowrie as well.
Primovula roseomaculata lives on soft corals of the genus Dendronephtya
Primovula roseomaculata usually live and feed on soft corals of the genus Dendronephtya. Due to the potent toxins used by these corals to deter predators, these cowries have adapted to only a single coral species. This behaviour has led to the rise of one of their common names, the “Allied Cowrie”. However, “Allied cowries” are in fact parasites, that harm their hosts. They feed on the coral’s tissues, mucus and polyps, and are able to absorb the pigments of their coral host, which enables these cowries to match their host’s colour so well. Not only that, but Primovula roseomaculata has the ability to even extract the defensive chemicals of the coral host, and store them in the skin of its own mantle, where they can protect the snail from fish predation! The host coral will continually regrow the lost tissue, so the cowrie never runs out of food, and or ammo!
How the cowrie finds their soft coral
They start their lives off as free-swimming post-larval juveniles and probably detect chemical clues that signal a potential host is nearby. Hosts are often home to several individuals. When settled, cowries graze up and down the coral and eventually deposit their eggs on a bare branch, beginning the cycle all over again.
There is more
Merry Christmas and save our oceans!