Image Keith Hiscock - Horseshoe worm, Phoronis hippocrepia in limestone. Image width ca 5cm.
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Phoronis hippocrepia is not listed under any importance categories.
|Recent synonyms||Larva originally described as Actinotropha hippocrepia Silén, 1954.|
|Recorded Distribution in Britain and Ireland||Found on all British and Irish coasts, especially common where rock is limestone.|
|Habitat information||Recorded from the intertidal zone near low tide mark to a maximum depth of 48 m. Both boring and encrusting forms inhabit similar substrata: rock, empty mollusc shells, coral skeletons, encrusting coralline algae and wood, although this species is commonly associated with calcareous substrata. Phoronis hippocrepia generally occurs under poor light conditions.|
|Description||Phoronis hippocrepia secretes and lives in a membranous, cylindrical tube, and occur in either boring or encrusting forms. Individuals are 0.3-1.5 mm in diameter and can grow up to 10 cm in height, although more commonly attain 4 cm. The body is cylindrical and elongate with a slender trunk (metasome) and a bulbous posterior (ampulla). Tentacles (terminal lophophore) occur entirely on the 'head' region, numbering 50-150. The tentacles are 2-3 mm in length and are arranged in a 'horse-shoe' shape. Individuals are translucent white greenish grey, yellowish or fleshy in colour.|
|Additional information||Phoronis hippocrepia can occur in densities of more than 20,000 individuals/m². Identification on this species may require microscopic work and dissection (see Emig, 1979). The only other known genus in this phylum is Phoronopsis. The genus Phoronis can be distinguished from Phoronopsis by the absence of a collar-fold below the lophophore (see Emig, 1979).|
This review can be cited as follows:
Susie Ballerstedt 2006. Phoronis hippocrepia. A horseshoe worm. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 19/06/2013]. Available from: <http://www.marlin.ac.uk/speciesinformation.php?speciesID=4108>