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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Invertebrate Zoology, 7th edition. Brachiopoda lamp shells Phoronida horseshoe worms.
A number of species bore into dead fillum, more rarely, live coral or other soft rocks, while one species even bores into a whale skull. The ratio between introvert and trunk length varies among species. Xenacoelomorpha Xenoturbellida Xenoturbella Acoelomorpha acoels nemertodermatids. Views Read Edit View history. Specific distribution map not available. They are found especially below the surface on tidal flats. Originally classified as annelidsdespite the complete lack of segmentation, bristles and other annelid characters, the phylum Sipuncula was later fillum with the Molluscamostly on the basis of developmental and larval characters.
At the posterior end of the trunk, a hardened caudal shield is sometimes present in Aspidosiphon ;  this may help with anchoring the animal in its burrow or may be used in the boring process. These gametes are then picked up by the metanephridia system and released into the aquatic environment, where fertilisation takes place. Micrognathozoa Limnognathia Syndermata Rotifera wheel animals Acanthocephala thorny-headed worms.
Used as bait in some parts of the world. Three genera AspidosiphonLithacrosiphon and Cloeosiphon in the Aspidosiphonidae family, possess epidermal structures modified for boring into rock; the anal shield is near the anteriorly located anus on the trunk just below the introvert of the animal.
The planktotrophic pelagosphera lasts up to six months in the water column before settling. The paleozoic Hyolitha has a mix of attributes of sipunculans and mollusks, suggesting a close phylogenetic relationship with both. Fishermen in various parts of the world use sipunculan worms, mostly the larger sand-dwelling species, as bait. Entoprocta or Kamptozoa Ectoprocta moss animals. This sipunculid worm filu, is made by adding vinegar and local spices.
The sipunculan nervous system consists of a cerebral ganglion and a ventral nerve cord. Longitudinal and circular body wall musculature in bands.
Sipunclans do not have a vascular blood system. In Aspidosiphon and Lithacrosiphon the anal shield is restricted to the dorsal side, causing the introvert to emerge at an angle, whereas it surrounds the anterior trunk in Cloeosiphon with the introvert emerging from its center. Placozoa Trichoplax Cnidaria jellyfish and relatives. The tentacles each have a deep groove along which food is moved to the mouth by cilia. The anus lies dorsally, usually at the anterior end of the trunk, except in sipuncila species where it is shifted anteriorly onto the introvert.
Some evidence points towards their involvement in ultrafiltration. In Quatrefages erected the group Gephyrea, which he considered an intermediate between worms and holothurians and which also contained echiurans, sternaspids, and priapulids.
It is a common meal for fisherfolk and is a sought-after but not so common appetizer in city restaurants.
Number of families 6 Thumbnail description Unsegmented marine worm-like animals with a body divided into a trunk and retractable introvert Photo: Nitrogenous waste is excreted through a pair of metanephridia opening close to the anus, except in Phascolion and Onchnesomawhich have only a single nephridium.
Some scientists once hypothesized a close relationship between sipunculans and the extinct hyolithsoperculate shells from the Palaeozoic with which they share a helical gut; but this hypothesis has since been discounted. Evolution and systematics No unambiguous fossil Sipuncula are currently known. Most sipunculans are deposit feeders, except representatives of the genus Themiste, which have elaborately branched tentacles used for filter feeding.
Trunk length eipuncula from a few millimeters to about Ecdysozoa Scalidophora Kinorhyncha mud dragons Priapulida penis worms. The anus is often not visible when the introvert is retracted into the trunk. Numerous papillae may be present on the trunk and introvert. Phylogenetic analyses based on 79 ribosomal proteins indicated a position of Sipuncula within Annelida.
When threatened, Sipunculids can contract their body into a sipunculz resembling a peanut kernel —a practice that has given rise to the name “peanut worm”.
Sipuncula – Wikipedia
These are proteinaceous, non-chitinous specializations of the epidermiseither arranged in rings or scattered. Orthonectida Dicyemida or Rhombozoa Monoblastozoa Salinella. Nematoida Nematoda roundworms Nematomorpha horsehair worms. Molecular Biology and Evolution. The worms, especially in dried form, are considered a delicacy in Vietnam as well, where they are caught on the coasts of Minh Chao island, in Van Don District.
Film hooks absent in adults. Only one species, Nephasoma minutum, is known to be hermaphroditic.
Asexual reproduction by budding has been reported in Aspidosiphon elegans. Peanut worm Phascolosoma sp. Gnathifera Chaetognatha arrow worms Gnathostomulida jaw worms.