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Phoronids: Phoronida

Behavior And Reproduction

Phoronids have extremely flexible bodies. They will quickly direct their lophophores to take full advantage of food-carrying ocean currents. Tiny bristles, or cilia (SIH-lee-uh), on their lophophores help carry bits of food trapped by sticky mucous on the tentacles down special grooves all the way to the mouth. They are also quick to respond to danger and will withdraw inside their tubes when they are threatened. If injured by a predator, phoronids can regenerate lost or damaged body parts in just a few days.

Phoronids reproduce in different ways. Sometimes both males and females are required to reproduce. In other species, individuals may have both male and female reproductive organs at the same time. This way, every phoronid is a potential mate. Phoronids can also reproduce without eggs and sperm at all. Instead, individuals simply divide their bodies, breaking off at the middle into halves. Each half quickly develops into a complete animal.


The name Phoronida comes from the Latin Phoronis, the last name of the mythological Io. Zeus, the king of gods, turned Io into a cow because he wanted to hide her from his wife. Io Phoronis wandered the Earth for many years, until she was returned to her original body. Phoronids were first discovered and known for many years only as larvae. It was only much later that they were associated with their tube-building adults.

Reproduction usually takes place from spring through fall. In most species, eggs and sperm are released, and fertilization usually takes place in the water. In a few species, the males produce sperm packets and transfer them directly to the female. Fertilization takes place inside the female's body cavity. The eggs develop in special tissues in the lophophore or inside the body cavity. The newly hatched larvae of all phoronids swim freely and live with other plankton. After about twenty days they settle to the bottom. In less than thirty minutes, they can transform into slender, young phoronids ready to burrow into their surroundings.

Additional topics

Animal Life ResourceMollusks, Crustaceans, and Related SpeciesPhoronids: Phoronida - Physical Characteristics, Habitat, Behavior And Reproduction, No Common Name (phoronis Ijimai): Species Account - GEOGRAPHIC RANGE, DIET, PHORONIDS AND PEOPLE, CONSERVATION STATUS