Phoronis hippocrepia (Phoronida, Phoronidae) is a shallow water phoronid boring in empty bivalve shells or living under bryozoan colonies and polychaete tubes. The chitinous tube secreted by the animal projects outwards the burrow, its external opening reaching about 0.8 mm in diameter. The maximum length of the animaI is about 2 mm. The lophophore – a crown of ciliated tentacles – and sometimes the distalmost part of the trunk are the only parts of the animal that appear outside the tube. The gut is u-shaped, the mount is inside the lophophore and the anus opens outside de lophophore.
P. hippocrepia is a simultaneous hermaphrodite species. The gametes are released through the nephridia, the newly shed eggs remaining on the bottom of the brood-pouch formed by the lophophore cavity. Usually several embryos at various stages of development are brooded. According to Forneris (1959) the “egg takes about four days to develop into a young larva.” The larva remains attached to the brood chamber at the hood. They freed themselves to the water – where they begin their planktonic life phase –, when they have 6 or 8 larval tentacles. The larval free-swimming period lasts 9 to 12 days, when the larva metamorphoses and begins its benthic stage (Forneris, 1959).

Want to know more about what is a phoronid? Give a look at:

Emig C. C. & C. de Mittelwihr, 1999. What is a phoronid? [ Ссылка ]

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Forneris, L. 1959. Phoronidae from Brazil. Bol. Inst. Oceanogr. vol.10 no.2 São Paulo. [ Ссылка ]

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