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Phylum Sipuncula In: Atkinson LJ and Sink KJ (eds). Field Guide to the Ofshore Marine Invertebrates of South Africa,. Malachite Marketing and Media, Pretoria. Sipuncula is a clade of unsegmented, coelomate marine worms. . Sipuncula, however, with sipunculans as an annelid ingroup, other. Phylum Sipuncula. Class Phascolosomatidea. Order Aspidosiphoniformes. Family Aspidosiphonidae. Aspidosiphon Diesing, Aspidosiphon elegans.

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Journal siphncula Zoological Systematics and Evolutionary Research. Evolution and systematics No unambiguous fossil Sipuncula are currently known.

Echinodermata starfish and relatives Hemichordata acorn worms pterobranchs. Distinguished by number of longitudinal muscle bands: The tentacles are rarely visible above the seafloor during the day, but may be extended at night to probe the surrounding sediment for food particles.

Sipuncula signifies “little tube or siphon”. Abundance ranges from rare to extremely common e.

In Java, in the western Carolines, and in some parts of China, sipunculans are eaten by eipuncula locals. American Zoologist, 16, — When threatened, Sipunculids can contract their body into a shape resembling a peanut kernel —a practice that has given rise to the name “peanut worm”.

Most species retract their tentacles and introvert quickly following a sipuncupa stimulus. It is attached anteriorly to the body wall near the anus and posteriorly to either the body wall or inside the gut coil. Gametes are released into the coelom where maturation proceeds. The tentacles filu the contractile vessel fluid reservoir for tentacle extension contain a second coelomic compartment. Used as bait in some parts of the world. Invertebrate Biology, 150— Specific distribution map not available.


Arthropoda arthropods Tardigrada waterbears. Sipunculans have a body wall somewhat similar to that of annelids though unsegmented in that it consists of a non-ciliated epidermis overlain by a cuticle, an outer layer of circular and an inner layer of longitudinal musculature.

Phascolion strombus, an inhabitant of gastropod shells, is able to irrigate its shell to increase oxygen content by contractions of the body wall musculature. Filuum the early seventeenth century, Sipuncula were considered close relatives of holothurians.

A spindle muscle runs through the gut coil. Sand-dwelling species ingest sediment and associated biomass that they collect with their tentacles. Sipunclans do not have a vascular blood system. Views Read Edit View history. Currently these two phyla have been included in a larger group, the Lophotrochozoathat also includes the annelidsthe ribbon worms and several other phyla.

Sipuncu,a the posterior end of the trunk, a hardened caudal shield is sometimes present in Aspidosiphon ; [6] this may help with anchoring the animal in its burrow or may sipuncul used in the boring process. In the trunk the intestine runs posteriorly, forms a loop and sjpuncula anteriorly again.

Phylum Sipuncula

The nervous system consists of a nerve ring the cerebral ganglion around the oesophagus, which functions as a brain, and a single ventral nerve cord that runs the length of the body. A sipunculan with introvert everted left and retracted.


Scottish Journal of Geology. The coelomic fluid contains five types of coelomic cells: The nephridiopores lie ventro-laterally, typically at the level of the anus.

Phylum Sipuncula

Ot-toia prolifica from the Burgess Shale has been proposed as a fossil sipunculan, but might also be an aschelminth or Pria-pulida. The phylum Sipuncula contains two classes, four orders, six families, 17 genera, and species.

The downward and upward sections of the gut are coiled around each other, forming a double helix. Although some species hatch directly sipundula the adult form, many have a trochophore larva, which metamorphoses into the adult after anything from a day to a month, depending on species.

This page sipuncyla last edited on 6 Decemberat Taken in CebuPhilippines. The intestine is characteristically U-shaped, with the ascending and descending branches coiled around each other in a double helix.

A sipunculid worm dish is also a delicacy in the islands of the Visayas region, Philippines.