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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Ecdysozoa Scalidophora Kinorhyncha mud dragons Priapulida penis worms. Abundance sipunculz from rare to extremely common e. Dioecious; indirect developer with lecithotrophic trochophora and long-lived planktotrophic pelagosphera.
In other projects Wikimedia Commons Wikispecies. In Aspidosiphon the shield is a hardened, horny structure; in Lithacrosiphon it is a calcareous cone; in Cloeosiphon it is composed of separate plates.
Taken in CebuPhilippines. The body wall musculature is composed of an outer layer of longitudinal and an inner layer sipnucula circular muscles. Rock-dwelling species use their sipuncuula hooks, mostly at nighttime, to scrape sediment and epifaunal organisms from the surrounding rock surface. Sipunculids are all marine. Cosmopolitan in intertidal and shallow tropical and subtropical waters. Some evidence points towards their involvement in ultrafiltration. Sand-dwelling species ingest sediment and associated biomass that they collect with their tentacles.
Asexual reproduction by budding has been reported in Aspidosiphon elegans.
Sipuncula – Wikipedia
Distinguished by number of longitudinal muscle bands: It can be protruded from the trunk by contracting the muscles of the trunk wall, thus forcing the fluid in the body cavity forwards. Scottish Journal of Geology.
Longitudinal and circular body wall musculature in bands. Echinodermata starfish and relatives Hemichordata acorn worms pterobranchs. Gametes are released into the coelom where maturation proceeds. The worms stay submerged in the sea bed between 10 and 18 hours a day and are sensitive to sipujcula, and thus not commonly filkm near estuaries.
In Quatrefages erected the group Gephyrea, which he considered an intermediate between worms and holothurians and which also contained echiurans, sternaspids, and priapulids. Cosmopolitan in temperate, subtropical, and tropical sipuncila in subtidal zone to 2, ft m depth. The paleozoic Hyolitha has a mix of attributes of sipunculans and mollusks, suggesting a close phylogenetic relationship with both.
Specific distribution map not available.
The specimen was dissected by Lankester between rounds of golf at Saint Andrews golf club in Scotland from which the species derives its name. 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. In the family Themistidae the tentacles forms a crown, as the members of this group are specialized filter feedersunlike the other sipunculans which are deposit feeders.
The anus is often not visible when the introvert is retracted into the trunk. Brachiopoda lamp shells Phoronida horseshoe worms. 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.
Most sipunculan species are dioecious. The introvert is pulled inside the trunk by two pairs of retractor muscles that extend as narrow ribbons from the trunk wall to attachment points in the introvert. 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”.
These gametes are then picked up by the metanephridia system and released into the aquatic environment, where fertilisation takes place.
Filumm planktotrophic pelagosphera lasts up to six months in the water column before settling. Most sipunculans are deposit feeders, except representatives of the genus Themiste, which have elaborately branched tentacles used for filter feeding. At the termination of the gut coil, the rectum emerges and ends in the anus.
The sipunculan body is divided into an unsegmented, bulbous trunk and a narrower, anterior section, called the “introvert”. Gonads are only prevalent during the reproductive period. Journal of Zoological Systematics and Evolutionary Research.
Kinorhyncha mud dragons Priapulida penis worms. Two nephridia are present, except in the genera Phasco-lion and Onchnesoma, which have only a single nephridium. A large coelom represents the main body cavity.
The first species of this phylum was described in by the French zoologist Henri Marie Ducrotay de Blainville who named it Sipunculus vulgaris. A number of species bore into dead or, more rarely, live coral or other soft rocks, while one species even bores into a whale skull.
A related species was later described as Golfingia macintoshii by E. Chaetognatha arrow worms Gnathostomulida jaw worms. 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.