Porpitidae Family of Chondronophores
Two Chondronophores of the Porpitidae Family can be found in this Website:
Phylogeny: Chondronophores and Porpitids of the Porpitidae Family, like Sea Anemones, Jellyfish, and Hydroids, belong to the phylum Cnidaria. They are in the subphylum Medusazoa, the class Hydrozoa, the subclass Hydroidolina, the order Anthoathecata, and the suborder Capitata. The Porpitidae Family is one of nineteen families in this suborder. The Porpitidae Family is very small, with only two genera and three species. Chondronophores are Athecate Hydroids indicative that in their polyp stage, they are unprotected by a holster in contrast to Thecate Polyps. The name Porpitidae comes from the Greek word meaning “brooch” or “stud”, and refers to the flat circular shape of these animals.
Morphology: Chondronophores are dark blue in color. They appear to be a single organism but in reality, they are a colony of four types of multi-cellular, interdependent, animals (zooids). They consist of a gas-filled disk that provides buoyancy, and short tentacles. Some species have a disk that has a sail-like structure that catches the wind and provides locomotion. The disk and sail are chitinous giving them the feel of stiff plastic. The sail may be right- or left-handed, which determines which direction they travel. They reach a maximum of 7.6 cm (3.0 inches) in diameter.
Habitat and Distribution: Chondronophores are usually found in large groups, either floating on the surface in open water, or washed up on the beach. They are not able to swim or dive, and are at the mercy of the wind. Chondronophores are found worldwide, in temperate to tropical seas. Two species in the Porpitidae Family are found in Mexican waters.
Reproduction: Chondronophores have a bipartite life cycle, with a polyp form and a medusa form. The photograph above exhibits the most commonly seen polyp form, but this polyp will release tiny medusae during asexual reproduction. These medusae mature and reproduce sexually when egg and sperm meet to form a new polyp.
Ecosystem Roles: Chondronophores are zooxanthellate. They have a symbiotic relationship with single-cell dinoflagellates, known as zooxanthellae. The zooxanthellae produce energy, during daylight, by means of photosynthesis. This energy is passed along to their hosts, sometimes providing up to 90% of the host’s total energy needs. In return, the host provides nutrients, carbon dioxide, and a secure, sunlit, platform for the zooxanthellae. They supplement this energy source by being suspension predators, feeding on small zooplankton such as fish eggs, euphausiid eggs, copepods, larvaceans and crustacean larvae. They use their tentacles to sting and capture their prey, and to move it to specialized digestive polyps. In turn they are preyed upon by the Ocean Sunfish, Mola mola, the Loggerhead Sea Turtle, Caretta caretta, nudibranchs of the genus Glaucus, and the Violet Sea-snail, Janthina janthina.