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Phoronida Horseshoe worms

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Higher taxa:  Life   Phoronida   IDnature guide: Groups_other We parsed the following live from the Web into this page. Such content is managed by its original site and not cached on Discover Life. Please send feedback and corrections directly to the source. See original regarding copyrights and terms of use. Museum of Paleontology, University of California, Berkeley

Kinds

Phoronidae

Overview

A small group of sessile, wormlike marine lophotrochozoans that secrete chitinous tubes and feed using a lophophore.

Phylogeny

Tree of Life

Links to other sites

Phoronida, Wikipedia General Information on Phoronida, University of Guelph, Canada

Acknowledgements

Ashley MacDonald, University of Georgia, Athens I thank John Pickering for his assistance with the development of this page.

Following modified from Museum of Paleontology, University of California, Berkeley

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Introduction to the Phoronida The Phoronida is one of the smallest and least familiar phyla; there are about twelve or so living species in two genera, Phoronis and Phoronopsis . However, phoronids -- or "horseshoe worms," as they are sometimes called -- may be abundant in shallow marine sediments at certain localities. Phoronids are elongated and worm- shaped, but the gut loops and ends close to the mouth, instead of passing straight through the body as in annelids and many other wormlike organisms. The mouth is surrounded by the ciliated feeding structure known as a lophophore . The lophophore of phoronids is a simple ring in some species, folded into a horseshoe shape in others, as shown in Phoronopsis viridis above (hence the common name "horseshoe worms"), and coiled in other species. There are no known body fossils of phoronids, probably because their bodies are completely soft. However, some phoronids secrete tubes of agglutinated sediment, as shown here, around their bodies. These might be preserved as fossils, but recognizing the identity of the maker would be almost impossible, since various annelids , arthropods , and members of other phyla leave similar traces. A few phoronids bore into shells or calcareous rocks, making distinctive holes. The oldest phoronid-like boring, which has been given the form name Talpina , is Devonian . Phoronida Links: Phoronida Net courtesy of Christian C. Emig