662:. When burrowing, the proboscis is raised and folded backwards and plays no part in the digging process. The front of the trunk is shaped into a wedge and pushed forward, with the two anterior chaetae (hooked chitinous bristles) being driven into the sediment. Next the rear end of the trunk is drawn forward and the posterior chaetae anchor it in place. These manoeuvres are repeated and the worm slowly digs its way forwards and downwards. It takes about forty minutes for the worm to disappear from view. The burrow descends diagonally and then flattens out, and it may be a metre or so long before ascending vertically to the surface.
1015:
674:
980:
113:
995:
543:
272:
135:
1035:
666:
2274:
852:
368:. In 1898, Sedgwick raised the sipunculids and priapulids to phylum status but considered Echiuroids to be a class of the Annelida. During the early 1900s, a biologist named Jon Stanton Whited devoted his working life to study the echiurans and classify many of its different species. In 1940, after the American marine biologist W. W. Newby had studied the embryology and development of
690:, extending the flexible and mobile proboscis and gathering organic particles that are within reach. Some species can expand the proboscis by ten times its contracted length. The proboscis is moved by the action of cilia on the lower (ventral) surface "creeping" it forward. When food particles are encountered, the sides of the proboscis curl inward to form a ciliated channel.
2262:
308:, but echiurans have secondarily lost their segmentation. The majority of echiurans live in burrows in soft sediment in shallow water, but some live in rock crevices or under boulders, and there are also deep sea forms. More than 230 species have been described. Spoon worms are cylindrical, soft-bodied animals usually possessing a non-retractable
810:. The sperm and eggs complete their maturation in the body cavity, before being stored in genital sacs, which are specialised metanephridia. At spawning time, the genital sacs contract and the gametes are squeezed into the water column through pores on the worm's ventral surface. Fertilization is external.
721:
and food particles stick to the net. When this is sufficiently clogged up, the spoon worm moves forward along its burrow devouring the net and the trapped particles. This process is then repeated and in a nutrient-rich area may take only a few minutes to complete. Large particles are squeezed out of
533:
for excreting nitrogenous waste, which typically open near the anterior end of the animal. The nervous system consists of a brain near the base of the proboscis, and a ventral nerve cord running the length of the body. Aside from the absence of segmentation, this is a similar arrangement to that of
750:
obtains its food by another method. it has two vertical burrows connected by a horizontal one. Stretching out its proboscis across the substrate it shovels material into its mouth before separating the edible particles. It can lengthen the proboscis dramatically while exploring new areas and
717:. It has a short proboscis and a ring of mucous glands at the front of its body. It expands its muscular body wall to deposit a ring of mucus on the burrow wall then retreats backwards, exuding mucus as it goes and spinning a mucus net. It then draws water through the burrow by
484:, there are also further setae near the posterior end of the animal. Unlike most annelids, adult echiurans have no trace of segmentation. Most echiurans are a dull grey or brown but a few species are more brightly coloured, such as the translucent green
312:
which can be rolled into a scoop-shape to feed. In some species the proboscis is ribbon-like, longer than the trunk and may have a forked tip. Spoon worms vary in size from less than a centimetre in length to more than a metre.
1930:
The food composition of the symbiotic crab
Pinnixa rathbunae Sakai, 1934 (Brachyura: Pinnotheridae) from burrows of the spoon worm Urechis unicinctus (von Drasche, 1881 (Echiurida: Urechidae) in Vostok Bay of the Sea of
821:
larvae. In some species, the larva briefly develops a segmented body before transforming into the adult body plan, supporting the theory that echiurans evolved from segmented ancestors resembling more typical annelids.
843:. Females are typically 15 cm (6 in) in body length, excluding the proboscis, but the males are only 1 to 3 mm (0.04 to 0.12 in) long, and spend their adult lives within the uterus of the female.
497:
which leads to a long looped intestine with an anus at the rear tip of the body. The intestine is highly coiled, giving it a considerable length in relation to the size of the animal. A pair of simple or branched
813:
Fertilization is internal in the sexual dimorphic order
Bonelliida, which has dwarf males living inside the female. Members of the order Echiurida have external fertilization and are sexual monomorphic.
402:
period. This exhibits a proboscis, cigar‐shaped body and convoluted gut, and shows that already at that time, echiurans were unsegmented and were essentially similar to modern forms. However, U-shaped
457:
of other annelids. The proboscis has rolled-in margins and a groove on the ventral surface. The distal end is sometimes forked. The proboscis can be very long; in the case of the
Japanese species
1393:
Struck, T. H.; Paul, C.; Hill, N.; Hartmann, S.; Hösel, C.; Kube, M.; Lieb, B.; Meyer, A.; Tiedemann, R.; Purschke, G. N.; Bleidorn, C. (2011). "Phylogenomic analyses unravel annelid evolution".
1307:; Schmidt-Rhaesa, A.; Okusu, A.; Kristensen, R. M. B.; Wheeler, W. C.; Martindale, M. Q.; Giribet, G. (2008). "Broad phylogenomic sampling improves resolution of the animal tree of life".
469:
can have a proboscis a metre (yard) long. The proboscis is used primarily for feeding. Respiration takes place through the proboscis and the body wall, with some larger species also using
751:
periodically reverses its orientation in the burrow so as to use the back entrance to feed. Other spoon worms live concealed in rock crevices, empty gastropod shells, sand dollar
441:, measuring just 1 cm (0.4 in). Their bodies are generally cylindrical with two wider regions separated by a narrower region. There is a large extendible, scoop-shaped
774:(break off) if attacked and the worm will regenerate a proboscis over the course of a few weeks. In a study in California, one of the most commonly found dietary items of the
510:
funnels that open directly into the body cavity, and are presumed to be excretory organs. The proboscis has a small coelomic cavity separated from the main coelom by a
1639:
705:
and these are passed along the feeding groove by cilia to the mouth. The proboscis is periodically withdrawn into the burrow and later extended in another direction.
697:, living in the sediment, extends its proboscis from the rim of its burrow with the ventral side on the substrate. The surface of the proboscis is well equipped with
2512:
2402:
521:. Although some species lack a blood vascular system, where it is present, it resembles that of other annelids. The blood is essentially colourless, although some
1014:
2040:"A comprehensive molecular phylogeny of spoon worms (Echiura, Annelida): Implications for morphological evolution, the origin of dwarf males, and habitat shifts"
2428:
1881:
1358:
Bourlat, S.; Nielsen, C.; Economou, A.; Telford, M. (2008). "Testing the new animal phylogeny: A phylum level molecular analysis of the animal kingdom".
517:
Echiurans do not have a distinct respiratory system, absorbing oxygen through the body wall of both the trunk and proboscis, and through the cloaca in
994:
480:(bristles). In most species, there are just two, located on the underside of the body just behind the proboscis, and often hooked. In others, such as
1303:
Dunn, C. W.; Hejnol, A.; Matus, D. Q.; Pang, K.; Browne, W. E.; Smith, S. A.; Seaver, E.; Rouse, G. W.; Obst, M.; Edgecombe, G. D.; Sørensen, M. V.;
2376:
1237:
643:
A spoon worm can move about on the surface by extending its proboscis and grasping some object before pulling its body forward. Some worms, such as
979:
2415:
534:
other annelids. Echiurans do not have any eyes or other distinct sense organs, but the proboscis is presumed to have a tactile sensory function.
381:
worms; as such, their ancestors were segmented worms but echiurans have secondarily lost their segmentation. Their presumed sister group is the
2182:
2155:
1623:
1831:
1694:
463:, the proboscis can be 150 centimetres (59 in) long while the body is only 40 centimetres (16 in). Even smaller species like
592:
live below 3,000 m (10,000 ft). They often congregate in sediments with high concentrations of organic matter. One species,
1929:
1780:
1750:
1677:
874:(개불). These worms are much prized and are often available at markets and stalls, chopped up and served raw in combination with raw
2474:
2237:
2207:
1994:
1215:
1140:
907:
1185:
2517:
2087:"Molecular Phylogeny of Echiuran Worms (Phylum: Annelida) Reveals Evolutionary Pattern of Feeding Mode and Sexual Dimorphism"
2420:
623:
outlets. The burrowing and feeding activities of these worms churned up and aerated the sediment and promoted a balanced
1034:
2350:
2278:
1829:(Echiura) on coastal shelf benthic communities and sediments modified by a major California wastewater discharge".
1001:
746:
547:
1770:
2433:
134:
673:
388:
Having no hard parts, these worms are seldom found as fossils. One of the oldest known unambiguous examples is
390:
399:
395:
542:
2290:
2039:
1866:
305:
1554:
Jones, D.; Thompson, I. D. A. (1977). "Echiura from the
Pennsylvanian Essex Fauna of northern Illinois".
1256:
584:). Others live in holes in coral heads, and in rock crevices. Some are found in deep waters including at
554:
Echiurans are exclusively marine and the majority of species live in the
Atlantic Ocean. They are mostly
364:(meaning a "bridge") in Annelida, because it was believed that they provided a link between annelids and
2451:
594:
112:
1021:
473:
irrigation. In this process, water is pumped into and out of the rear end of the gut through the anus.
2443:
2363:
2337:
2229:
2199:
2098:
2051:
2017:"Food habits of the leopard shark, Triakis semifasciata, in Elkhorn Slough, Monterey Bay, California"
1986:
1840:
1742:
1736:
1508:
1444:
Struck, T. H.; Schult, N.; Kusen, T.; Hickman, E.; Bleidorn, C.; McHugh, D.; Halanych, K. M. (2007).
1402:
1316:
1203:
607:
486:
2479:
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1132:
650:
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in front of the mouth which gives the animals their common name. This proboscis resembles that of
2502:
1967:
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1426:
1340:
1041:
863:
855:
465:
450:
343:
129:
1897:
437:
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1776:
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1536:
1477:
1418:
1375:
1332:
840:
836:
658:
612:
338:
2466:
2145:
1702:
598:, which lives off the southeastern coast of the US, inhabits the tests (exoskeleton) of dead
2116:
2106:
2059:
1959:
1848:
1563:
1526:
1516:
1467:
1457:
1410:
1367:
1324:
1177:
1163:"Animal biodiversity: An introduction to higher-level classification and taxonomic richness"
1082:
827:
678:
459:
431:
2407:
2016:
1871:
1026:
956:
580:
559:
253:
179:
2102:
2055:
1844:
1512:
1495:
Tilic, Ekin; Lehrke, Janina; Bartolomaeus, Thomas; Colgan, Donald James (3 March 2015).
1406:
1320:
1249:
Proceedings of the
International Symposium on the Biology of the Sipunculata and Echiura
602:. When the worm is very small, it enters the test and later becomes too large to leave.
2121:
2086:
1567:
1531:
1496:
1472:
1445:
1304:
752:
530:
755:
and similar places, extending their proboscises into the open water to feed. Some are
2496:
2328:
1876:
1852:
779:
775:
760:
714:
404:
370:
121:
70:
1162:
1430:
1344:
875:
727:
723:
665:
585:
563:
499:
382:
324:
of these worms are seldom found and the earliest known fossil specimen is from the
1581:
2111:
1943:
1521:
766:
While the proboscis of a burrowing spoon worm is on the surface it is at risk of
2389:
2342:
2322:
2063:
1371:
986:
921:
887:
851:
818:
718:
687:
616:
599:
589:
522:
418:
325:
227:
45:
2355:
2273:
1181:
1103:
1006:
947:
915:
883:
879:
832:
803:
735:
653:
entirely, swimming by use of the proboscis and contractions of the body wall.
454:
435:, nearly 2 m (7 ft) long with its proboscis extended, to the minute
365:
357:
247:
221:
192:
90:
55:
1885:. Vol. 08 (11th ed.). Cambridge University Press. pp. 882–883.
1046:
965:
941:
891:
795:
767:
756:
709:
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glands to which food particles adhere. The mucus is bundled into boluses by
632:
624:
446:
442:
353:
348:
309:
259:
241:
146:
95:
2313:
2130:
2071:
1540:
1481:
1462:
1422:
1379:
1336:
1086:
2261:
1825:
Stull, Janet K.; Haydock, C.Irwin; Montagne, David E. (1986). "Effects of
1068:"Echiuran worms from the Middle Ordovician Castle Bank Biota of Wales, UK"
529:
of the main body cavity. There can be anywhere from one to over a hundred
17:
2307:
1281:
930:
771:
645:
568:
555:
408:
361:
317:
301:
233:
85:
80:
65:
60:
50:
1414:
1328:
2381:
1971:
574:
449:
but it cannot be retracted into the body. It houses a brain and may be
378:
166:
100:
75:
2394:
807:
702:
620:
526:
511:
507:
503:
494:
470:
321:
297:
293:
156:
2284:
2174:
Korean
Functional Foods: Composition, Processing and Health Benefits
2085:
Goto, R.; Okamoto, T.; Ishikawa, H.; Hamamura, Y.; Kato, M. (2013).
1963:
669:
Characteristic forked proboscis of an echiurian worm in the
Maldives
1672:. Philadelphia, PA: Holt-Saunders International. pp. 870–873.
1870:
850:
799:
698:
672:
664:
628:
541:
290:
270:
862:
Spoon worms are eaten in East and
Southeast Asia. In South Korea
759:
or detritivores, while others are interface grazers and some are
619:
in numbers of up to 1,500 per square metre (11 square feet) near
2171:
Kun-Young Park; Dae Young Kwon; Ki Won Lee; Sunmin Park (2018).
1614:
Ruppert, Edward E.; Fox, Richard, S.; Barnes, Robert D. (2004).
739:
731:
477:
2288:
352:. In the mid-nineteenth century Echiura was placed, alongside
2368:
1497:"Homology and Evolution of the Chaetae in Echiura (Annelida)"
1238:"A restudy of the Middle Cambrian Burgess Shale fossil worm,
839:, the green chemical in its skin, is unusual for its extreme
806:
membrane lining the body cavity, into which they release the
770:
by bottom-feeding fish. In some species, the proboscis will
476:
Compared with other annelids, echiurans have relatively few
1446:"Annelid phylogeny and the status of Sipuncula and Echiura"
407:
that could be
Echiuran have been found dating back to the
377:
They are now universally considered to represent derived
1772:
Intertidal Invertebrates of the Central California Coast
558:, occupying burrows in the seabed, either in the lower
894:. They are also eaten as a fermented product known as
304:. Annelids typically have their bodies divided into
2297:
786:) which it extracted from the sediment by suction.
411:, and an Ordovician species of thalassematid named
631:than would otherwise have existed in this heavily
798:, with separate male and female individuals. The
588:depths; in fact more than half the 70 species in
493:The body wall is muscular. It surrounds a large
1775:. University of California Press. p. 108.
730:in the burrow. These typically include a small
342:was first described by the Prussian naturalist
1695:"Part 6: Phylum Sipuncula and Phylum Annelida"
346:in 1766; he placed it in the earth worm genus
1098:
1096:
713:, another group of tube-dwellers, has become
8:
1638:: CS1 maint: multiple names: authors list (
2285:
1699:Reefkeeper's Guide to Invertebrate Zoology
1609:
1607:
1605:
1603:
1601:
1599:
111:
31:
2120:
2110:
1530:
1520:
1471:
1461:
817:Fertilized eggs hatch into free-swimming
1820:
1818:
1730:
1728:
1726:
1724:
1722:
1720:
429:Spoon worms vary in size from the giant
374:, he raised the group to phylum status.
1126:
1124:
1058:
975:
742:lurking just inside the back entrance.
506:. These are lined with numerous minute
300:, they are now considered to belong to
27:Group of marine animals ("spoon worms")
2513:Extant Pennsylvanian first appearances
1631:
1618:. Cengage Learning. pp. 490–495.
656:Digging behaviour has been studied in
2144:Brown, Nicholas; Eddy, Steve (2015).
2044:Molecular Phylogenetics and Evolution
1944:"Feeding Mechanism of the Echiuroid,
1764:
1762:
1663:
1661:
1659:
1657:
1655:
1653:
1651:
1649:
1360:Molecular Phylogenetics and Evolution
525:-containing cells are present in the
316:Most are deposit feeders, collecting
7:
2444:3163b311-da42-4841-9c7a-ad346b162382
1832:Estuarine, Coastal and Shelf Science
1809:Stud. Biol. Lab. Johns Hopkins Univ.
1803:Conn, H.W. (1886). "Life history of
1738:Encyclopedia of Marine Invertebrates
1280:Elsberry, Wesley R. (10 June 2006).
1066:Botting, Joseph; Muir, Lucy (2023).
831:, also remarkable for the possible
1568:10.1111/j.1502-3931.1977.tb00627.x
778:was found to be the tube-dwelling
25:
1616:Invertebrate Zoology, 7th edition
2272:
2260:
2238:World Register of Marine Species
2208:World Register of Marine Species
1995:World Register of Marine Species
1236:Banta, W.C.; Rice, M.E. (1970).
1216:World Register of Marine Species
1191:from the original on 2022-10-09.
1141:World Register of Marine Species
1033:
1013:
993:
978:
908:World Register of Marine Species
398:in Illinois, dating back to the
133:
1910:Invertebrates of the Salish Sea
1948:Leuckart & Rueppell, 1828"
1:
1741:. TFH Publications. pp.
1582:"Introduction to the Echiura"
1075:Acta Palaeontologica Polonica
969:Fisher & Macginitie, 1928
605:In the 1970s, the spoon worm
296:. Once treated as a separate
2112:10.1371/journal.pone.0056809
1985:van der Land, Jacob (2004).
1853:10.1016/0272-7714(86)90020-X
1522:10.1371/journal.pone.0120002
2064:10.1016/j.ympev.2016.03.003
2038:Goto, Ryutaro (June 2016).
1584:. UC Museum of Paleontology
1372:10.1016/j.ympev.2008.07.008
722:the net and eaten by other
360:, in the now defunct class
2534:
2177:. CRC Press. p. 232.
1946:Ochetostoma erythrogrammon
1668:Barnes, Robert D. (1982).
1002:Ochetostoma erythrogrammon
960:Forbes & Goodsir, 1841
858:at a market in South Korea
747:Ochetostoma erythrogrammon
686:Spoon worms are typically
548:Ochetostoma erythrogrammon
2228:Tanaka, Masaatsu (2017).
2198:Tanaka, Masaatsu (2017).
1769:Felty Light, Sol (1954).
1202:Tanaka, Masaatsu (2017).
1182:10.11646/zootaxa.3148.1.3
1131:Tanaka, Masaatsu (2017).
217:
212:
130:Scientific classification
128:
119:
110:
34:
2021:California Fish and Game
1735:Walls, Jerry G. (1982).
1450:BMC Evolutionary Biology
802:are associated with the
719:peristaltic contractions
538:Distribution and habitat
1882:Encyclopædia Britannica
1867:Shipley, Arthur Everett
396:Mazon Creek fossil beds
391:Coprinoscolex ellogimus
289:, are a small group of
2147:Echinoderm Aquaculture
2015:Tallent, L.G. (1976).
1942:Chuang, S. H. (1962).
1463:10.1186/1471-2148-7-57
1087:10.4202/app.01107.2023
859:
683:
670:
551:
332:Taxonomy and evolution
278:
2518:Protostome subclasses
2452:Paleobiology Database
2150:. Wiley. p. 60.
1896:Cowles, Dave (2005).
1161:Zhang, Z.-Q. (2011).
985:A worm of the family
925:Lacaze-Duthiers, 1858
854:
676:
668:
545:
502:are connected to the
274:
2269:at Wikimedia Commons
1827:Listriolobus pelodes
1693:Toonen, Rob (2012).
1670:Invertebrate Zoology
627:with a more diverse
608:Listriolobus pelodes
487:Listriolobus pelodes
400:Middle Pennsylvanian
320:from the sea floor.
2103:2013PLoSO...856809G
2056:2016MolPE..99..247G
1952:Biological Bulletin
1872:"Echiuroidea"
1845:1986ECSS...22....1S
1513:2015PLoSO..1020002T
1415:10.1038/nature09864
1407:2011Natur.471...95S
1329:10.1038/nature06614
1321:2008Natur.452..745D
1284:. Online Zoologists
864:fat innkeeper worms
1805:Thalassema mellita
1042:Urechis unicinctus
868:Urechis unicinctus
860:
761:suspension feeders
684:
671:
595:Lissomyema mellita
552:
414:Llwygarua suzannae
344:Peter Simon Pallas
279:
41:Darriwilian–Recent
2490:
2489:
2291:Taxon identifiers
2265:Media related to
2184:978-1-351-64369-6
2157:978-1-119-00585-8
1900:Echiurus echiurus
1705:on 26 August 2012
1625:978-81-315-0104-7
1315:(7188): 745–749.
1305:Haddock, S. H. D.
1206:Echiurus echiurus
1022:Arhynchite hayaoi
970:
961:
952:
951:Quatrefages, 1847
935:
926:
906:According to the
841:sexual dimorphism
659:Echiurus echiurus
613:continental shelf
611:was found on the
566:(e.g. the genera
417:was found in the
339:Echiurus echiurus
326:Middle Ordovician
269:
268:
208:
16:(Redirected from
2525:
2483:
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2277:Data related to
2276:
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2219:
2218:
2216:
2214:
2195:
2189:
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2035:
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2012:
2006:
2005:
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2001:
1982:
1976:
1975:
1939:
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1927:
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1916:
1893:
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1794:
1793:
1791:
1789:
1766:
1757:
1756:
1732:
1715:
1714:
1712:
1710:
1701:. Archived from
1690:
1684:
1683:
1665:
1644:
1643:
1637:
1629:
1611:
1594:
1593:
1591:
1589:
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1434:
1390:
1384:
1383:
1355:
1349:
1348:
1300:
1294:
1293:
1291:
1289:
1282:"Phylum Echiura"
1277:
1271:
1270:
1268:
1267:
1261:
1255:. Archived from
1246:
1240:Ottoia prolifica
1233:
1227:
1226:
1224:
1222:
1199:
1193:
1192:
1190:
1167:
1158:
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1128:
1119:
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1114:
1100:
1091:
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1072:
1063:
1037:
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982:
968:
959:
950:
933:
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902:List of families
828:Bonellia viridis
679:Bonellia viridis
649:, can leave the
460:Ikeda taenioides
432:Ikeda taenioides
206:
138:
137:
115:
105:
42:
38:Temporal range:
32:
21:
2533:
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2143:
2142:
2138:
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2014:
2013:
2009:
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1964:10.2307/1539504
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1612:
1597:
1587:
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1579:
1575:
1553:
1552:
1548:
1507:(3): e0120002.
1494:
1493:
1489:
1443:
1442:
1438:
1401:(7336): 95–98.
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1391:
1387:
1357:
1356:
1352:
1302:
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1278:
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1234:
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1218:
1208:(Pallas, 1766)"
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1027:Thalassematidae
1018:
1009:
998:
989:
983:
957:Thalassematidae
904:
886:, dressed with
870:) are known as
849:
792:
693:A worm such as
641:
562:or the shallow
560:intertidal zone
540:
427:
334:
254:Thalassematidae
205:
180:Pleistoannelida
132:
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2289:
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2281:at Wikispecies
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2256:
2255:External links
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2156:
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2007:
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794:Echiurans are
791:
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780:innkeeper worm
715:filter feeders
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527:coelomic fluid
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405:burrow fossils
336:The spoonworm
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2027:(4): 286–298.
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1276:
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1262:on 2012-03-12
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789:
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785:
784:Urechis caupo
781:
777:
776:leopard shark
773:
769:
764:
762:
758:
754:
749:
748:
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724:invertebrates
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531:metanephridia
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421:lagerstätte.
420:
416:
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386:
384:
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372:
371:Urechis caupo
367:
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136:
131:
127:
124:
123:
122:Urechis caupo
118:
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109:
102:
97:
92:
87:
82:
77:
72:
67:
62:
57:
52:
47:
33:
30:
19:
2298:
2241:. Retrieved
2233:
2223:
2211:. Retrieved
2203:
2200:"Bonelliida"
2193:
2173:
2166:
2146:
2139:
2094:
2090:
2080:
2047:
2043:
2033:
2024:
2020:
2010:
1998:. Retrieved
1990:
1980:
1958:(1): 80–85.
1955:
1951:
1945:
1937:
1925:
1913:. Retrieved
1909:
1903:
1899:
1891:
1880:
1861:
1836:
1830:
1826:
1811:: 1884–1887.
1808:
1804:
1798:
1786:. Retrieved
1771:
1737:
1707:. Retrieved
1703:the original
1698:
1688:
1669:
1615:
1586:. Retrieved
1576:
1559:
1555:
1549:
1504:
1500:
1490:
1453:
1449:
1439:
1398:
1394:
1388:
1366:(1): 23–31.
1363:
1359:
1353:
1312:
1308:
1298:
1286:. Retrieved
1275:
1264:. Retrieved
1257:the original
1252:
1248:
1239:
1231:
1219:. Retrieved
1211:
1205:
1197:
1173:
1169:
1156:
1144:. Retrieved
1136:
1111:. Retrieved
1107:
1104:"Spoon Worm"
1078:
1074:
1061:
1040:
1020:
1000:
905:
895:
876:sea cucumber
871:
867:
861:
847:Culinary Use
826:
825:The species
824:
816:
812:
793:
790:Reproduction
783:
765:
745:
744:
738:and often a
708:
707:
694:
692:
688:detritivores
685:
677:
657:
655:
644:
642:
606:
604:
600:sand dollars
593:
579:
573:
567:
553:
546:
518:
516:
492:
485:
481:
475:
464:
458:
447:peanut worms
436:
430:
428:
412:
389:
387:
383:Capitellidae
376:
369:
366:holothurians
347:
337:
335:
315:
286:
282:
280:
275:
213:Subdivision
202:
186:
173:
120:
29:
2390:iNaturalist
2323:Wikispecies
2230:"Echiurida"
2050:: 247–260.
2000:30 November
1915:18 February
1902:subspecies
1839:(1): 1–17.
1788:30 November
1709:10 November
1288:17 February
1221:17 February
1146:17 February
987:Bonelliidae
922:Bonelliidae
896:gaebul-jeot
888:chili sauce
856:Spoon worms
819:trochophore
728:commensally
617:Los Angeles
590:Bonelliidae
523:haemoglobin
500:diverticula
419:Castle Bank
287:spoon worms
228:Bonelliidae
207:Newby, 1940
2497:Categories
1562:(4): 317.
1266:2019-02-17
1054:References
1007:Echiuridae
948:Echiuridae
934:Bock, 1942
916:Bonelliida
884:sea urchin
880:sea squirt
833:antibiotic
804:peritoneal
772:autotomise
757:scavengers
736:scale worm
455:prostomium
451:homologous
438:Lissomyema
358:Priapulida
248:Echiuridae
222:Bonelliida
199:Subclass:
193:Sedentaria
18:Spoon worm
2503:Echiurans
1904:alaskanus
1634:cite book
1133:"Echiura"
1047:Urechidae
1045:, family
1025:, family
1005:, family
966:Urechidae
942:Echiurida
940:suborder
914:suborder
892:soy sauce
796:dioecious
768:predation
710:Urechidae
651:substrate
639:Behaviour
625:ecosystem
443:proboscis
394:from the
354:Sipuncula
349:Lumbricus
310:proboscis
260:Urechidae
242:Echiurida
153:Kingdom:
147:Eukaryota
2508:Annelids
2308:Wikidata
2131:23457618
2091:PLOS ONE
2072:26975690
1869:(1911).
1541:25734664
1501:PLOS ONE
1482:17411434
1423:21368831
1380:18692145
1337:18322464
1186:Archived
1176:: 7–12.
931:Ikedidae
837:bonellin
695:Echiurus
682:, female
646:Echiurus
633:polluted
569:Echiurus
564:subtidal
556:infaunal
508:ciliated
482:Echiurus
466:Bonellia
409:Cambrian
362:Gephyrea
318:detritus
306:segments
302:Annelida
276:Echiurus
234:Ikedidae
167:Annelida
163:Phylum:
157:Animalia
143:Domain:
2467:8275134
2382:7062236
2356:Echiura
2343:Echiura
2329:Echiura
2299:Echiura
2279:Echiura
2267:Echiura
2243:9 March
2213:9 March
2122:3572977
2099:Bibcode
2052:Bibcode
1972:1539504
1879:(ed.).
1841:Bibcode
1743:262–267
1588:7 March
1556:Lethaia
1532:4348511
1509:Bibcode
1473:1855331
1431:4428998
1403:Bibcode
1345:4397099
1317:Bibcode
1170:Zootaxa
1113:9 March
964:family
955:family
946:family
929:family
920:family
808:gametes
726:living
586:abyssal
575:Urechis
519:Urechis
471:cloacal
453:to the
425:Anatomy
379:annelid
322:Fossils
294:animals
283:Echiura
258:Family
252:Family
246:Family
232:Family
226:Family
203:Echiura
35:Echiura
2464:uBio:
2441:NZOR:
2421:914211
2395:117589
2314:Q64119
2181:
2154:
2129:
2119:
2070:
1970:
1779:
1749:
1676:
1622:
1539:
1529:
1480:
1470:
1456:: 57.
1429:
1421:
1395:Nature
1378:
1343:
1335:
1309:Nature
872:gaebul
800:gonads
699:mucous
635:area.
621:sewage
578:, and
512:septum
504:rectum
495:coelom
298:phylum
291:marine
240:Order
220:Order
2475:WoRMS
2457:67169
2403:IRMNG
2234:WoRMS
2204:WoRMS
1991:WoRMS
1968:JSTOR
1931:Japan
1875:. In
1427:S2CID
1341:S2CID
1260:(PDF)
1245:(PDF)
1212:WoRMS
1189:(PDF)
1166:(PDF)
1137:WoRMS
1071:(PDF)
753:tests
703:cilia
629:fauna
581:Ikeda
478:setae
285:, or
187:Clade
174:Clade
2480:1269
2434:6427
2429:NCBI
2416:ITIS
2408:1387
2377:GBIF
2369:8847
2245:2019
2215:2019
2179:ISBN
2152:ISBN
2127:PMID
2068:PMID
2002:2011
1917:2019
1790:2011
1777:ISBN
1747:ISBN
1711:2012
1674:ISBN
1640:link
1620:ISBN
1590:2019
1537:PMID
1478:PMID
1419:PMID
1376:PMID
1333:PMID
1290:2019
1223:2019
1174:3148
1148:2019
1115:2019
890:and
882:and
740:fish
734:, a
732:crab
615:off
356:and
281:The
46:PreꞒ
2364:EoL
2351:AFD
2338:ADW
2117:PMC
2107:doi
2060:doi
1960:doi
1956:123
1849:doi
1807:".
1564:doi
1527:PMC
1517:doi
1468:PMC
1458:doi
1411:doi
1399:471
1368:doi
1325:doi
1313:452
1178:doi
1083:doi
2499::
2477::
2454::
2431::
2418::
2405::
2392::
2379::
2366::
2353::
2340::
2325::
2310::
2236:.
2232:.
2206:.
2202:.
2125:.
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