651:. 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.
1004:
663:
969:
102:
984:
532:
261:
124:
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357:. 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
679:, 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.
297:, 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
799:. 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.
710:
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
522:
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
739:
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
706:. 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
473:, 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
301:
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.
1919:
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
810:
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.
832:. 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.
486:
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
802:
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.
391:
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
446:
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
1382:
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".
1296:; 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".
458:
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
740:
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
430:, 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
763:(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
499:
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
694:
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.
686:, 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
379:
510:. 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
2029:"A comprehensive molecular phylogeny of spoon worms (Echiura, Annelida): Implications for morphological evolution, the origin of dwarf males, and habitat shifts"
583:
1347:
Bourlat, S.; Nielsen, C.; Economou, A.; Telford, M. (2008). "Testing the new animal phylogeny: A phylum level molecular analysis of the animal kingdom".
1010:
506:
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
469:(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
1292:
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.;
1226:
632:
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
1628:
2501:
2391:
523:
other annelids. Echiurans do not have any eyes or other distinct sense organs, but the proboscis is presumed to have a tactile sensory function.
370:
worms; as such, their ancestors were segmented worms but echiurans have secondarily lost their segmentation. Their presumed sister group is the
1003:
2417:
426:
402:
1870:
1683:
825:
452:, the proboscis can be 150 centimetres (59 in) long while the body is only 40 centimetres (16 in). Even smaller species like
983:
581:
live below 3,000 m (10,000 ft). They often congregate in sediments with high concentrations of organic matter. One species,
1918:
2365:
863:(개불). These worms are much prized and are often available at markets and stalls, chopped up and served raw in combination with raw
2404:
968:
1174:
2171:
2144:
2076:"Molecular Phylogeny of Echiuran Worms (Phylum: Annelida) Reveals Evolutionary Pattern of Feeding Mode and Sexual Dimorphism"
1612:
2409:
1820:
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outlets. The burrowing and feeding activities of these worms churned up and aerated the sediment and promoted a balanced
1769:
1739:
1666:
2463:
2267:
2226:
2196:
1983:
1818:(Echiura) on coastal shelf benthic communities and sediments modified by a major California wastewater discharge".
1204:
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377:
Having no hard parts, these worms are seldom found as fossils. One of the oldest known unambiguous examples is
388:
1023:
2028:
2339:
1543:
Jones, D.; Thompson, I. D. A. (1977). "Echiura from the
Pennsylvanian Essex Fauna of northern Illinois".
1245:
573:). Others live in holes in coral heads, and in rock crevices. Some are found in deep waters including at
543:
Echiurans are exclusively marine and the majority of species live in the
Atlantic Ocean. They are mostly
353:(meaning a "bridge") in Annelida, because it was believed that they provided a link between annelids and
990:
735:
536:
462:
irrigation. In this process, water is pumped into and out of the rear end of the gut through the anus.
2432:
2218:
2188:
2006:"Food habits of the leopard shark, Triakis semifasciata, in Elkhorn Slough, Monterey Bay, California"
1975:
1731:
1725:
1433:
Struck, T. H.; Schult, N.; Kusen, T.; Hickman, E.; Bleidorn, C.; McHugh, D.; Halanych, K. M. (2007).
1192:
123:
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in front of the mouth which gives the animals their common name. This proboscis resembles that of
384:
1886:
2445:
2279:
1855:
294:
2161:
2455:
2440:
2134:
1691:
587:, which lives off the southeastern coast of the US, inhabits the tests (exoskeleton) of dead
1152:"Animal biodiversity: An introduction to higher-level classification and taxonomic richness"
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2005:
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8:
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1833:
1501:
1484:
Tilic, Ekin; Lehrke, Janina; Bartolomaeus, Thomas; Colgan, Donald James (3 March 2015).
1395:
1309:
1238:
Proceedings of the
International Symposium on the Biology of the Sipunculata and Echiura
591:. When the worm is very small, it enters the test and later becomes too large to leave.
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and similar places, extending their proboscises into the open water to feed. Some are
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313:
of these worms are seldom found and the earliest known fossil specimen is from the
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1932:
1813:
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While the proboscis of a burrowing spoon worm is on the surface it is at risk of
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entirely, swimming by use of the proboscis and contractions of the body wall.
515:
424:, nearly 2 m (7 ft) long with its proboscis extended, to the minute
2485:
1874:. Vol. 08 (11th ed.). Cambridge University Press. pp. 882–883.
1865:
768:
764:
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703:
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59:
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glands to which food particles adhere. The mucus is bundled into boluses by
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716:
712:
574:
552:
488:
371:
1814:
Stull, Janet K.; Haydock, C.Irwin; Montagne, David E. (1986). "Effects of
1057:"Echiuran worms from the Middle Ordovician Castle Bank Biota of Wales, UK"
518:
of the main body cavity. There can be anywhere from one to over a hundred
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34:
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1960:
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but it cannot be retracted into the body. It houses a brain and may be
354:
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Korean
Functional Foods: Composition, Processing and Health Benefits
2074:
Goto, R.; Okamoto, T.; Ishikawa, H.; Hamamura, Y.; Kato, M. (2013).
1952:
840:
658:
Characteristic forked proboscis of an echiurian worm in the
Maldives
2296:
2262:
1661:. Philadelphia, PA: Holt-Saunders International. pp. 870–873.
919:
760:
634:
557:
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350:
306:
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222:
74:
69:
54:
49:
39:
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Spoon worms are eaten in East and
Southeast Asia. In South Korea
748:
or detritivores, while others are interface grazers and some are
608:
in numbers of up to 1,500 per square metre (11 square feet) near
563:
367:
155:
89:
64:
2160:
Kun-Young Park; Dae Young Kwon; Ki Won Lee; Sunmin Park (2018).
1603:
Ruppert, Edward E.; Fox, Richard, S.; Barnes, Robert D. (2004).
2250:
796:
691:
609:
500:
496:
492:
483:
459:
341:. In the mid-nineteenth century Echiura was placed, alongside
310:
286:
282:
145:
2357:
1486:"Homology and Evolution of the Chaetae in Echiura (Annelida)"
1483:
1346:
1227:"A restudy of the Middle Cambrian Burgess Shale fossil worm,
828:, the green chemical in its skin, is unusual for its extreme
795:
membrane lining the body cavity, into which they release the
788:
687:
617:
279:
759:
by bottom-feeding fish. In some species, the proboscis will
465:
Compared with other annelids, echiurans have relatively few
2073:
1435:"Annelid phylogeny and the status of Sipuncula and Echiura"
728:
720:
466:
2132:
396:
that could be
Echiuran have been found dating back to the
366:
They are now universally considered to represent derived
1761:
Intertidal Invertebrates of the Central California Coast
1432:
547:, occupying burrows in the seabed, either in the lower
1381:
883:. They are also eaten as a fermented product known as
1224:
293:. Annelids typically have their bodies divided into
1973:
1291:
1268:
775:) which it extracted from the sediment by suction.
400:, and an Ordovician species of thalassematid named
620:than would otherwise have existed in this heavily
1656:
787:, with separate male and female individuals. The
577:depths; in fact more than half the 70 species in
2483:
2216:
2186:
1602:
1190:
1119:
482:The body wall is muscular. It surrounds a large
1764:. University of California Press. p. 108.
719:in the burrow. These typically include a small
331:was first described by the Prussian naturalist
1684:"Part 6: Phylum Sipuncula and Phylum Annelida"
335:in 1766; he placed it in the earth worm genus
2003:
1930:
1542:
1087:
1085:
702:, another group of tube-dwellers, has become
1884:
1627:: CS1 maint: multiple names: authors list (
1149:
1757:
1681:
1054:
526:
1791:
1688:Reefkeeper's Guide to Invertebrate Zoology
1598:
1596:
1594:
1592:
1590:
1588:
1375:
1340:
1082:
100:
2109:
2099:
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806:Fertilized eggs hatch into free-swimming
320:
1809:
1807:
1719:
1717:
1715:
1713:
1711:
1709:
1143:
839:
661:
653:
530:
418:Spoon worms vary in size from the giant
363:, he raised the group to phylum status.
259:
1854:
1585:
1285:
1115:
1113:
731:lurking just inside the back entrance.
495:. These are lined with numerous minute
289:, they are now considered to belong to
16:Group of marine animals ("spoon worms")
2502:Extant Pennsylvanian first appearances
2484:
1607:. Cengage Learning. pp. 490–495.
1426:
645:Digging behaviour has been studied in
2278:
2277:
2133:Brown, Nicholas; Eddy, Steve (2015).
2033:Molecular Phylogenetics and Evolution
1933:"Feeding Mechanism of the Echiuroid,
1804:
1753:
1751:
1723:
1706:
1652:
1650:
1648:
1646:
1644:
1642:
1640:
1638:
1349:Molecular Phylogenetics and Evolution
514:-containing cells are present in the
305:Most are deposit feeders, collecting
2433:3163b311-da42-4841-9c7a-ad346b162382
2026:
1821:Estuarine, Coastal and Shelf Science
1798:Stud. Biol. Lab. Johns Hopkins Univ.
1792:Conn, H.W. (1886). "Life history of
1727:Encyclopedia of Marine Invertebrates
1269:Elsberry, Wesley R. (10 June 2006).
1110:
1055:Botting, Joseph; Muir, Lucy (2023).
890:
820:, also remarkable for the possible
13:
1748:
1635:
1557:10.1111/j.1502-3931.1977.tb00627.x
767:was found to be the tube-dwelling
14:
2518:
2243:
1605:Invertebrate Zoology, 7th edition
2261:
2249:
2227:World Register of Marine Species
2197:World Register of Marine Species
1984:World Register of Marine Species
1225:Banta, W.C.; Rice, M.E. (1970).
1205:World Register of Marine Species
1180:from the original on 2022-10-09.
1130:World Register of Marine Species
1022:
1002:
982:
967:
897:World Register of Marine Species
387:in Illinois, dating back to the
122:
32:
2210:
2180:
2153:
2126:
2067:
2020:
1997:
1967:
1924:
1912:
1899:Invertebrates of the Salish Sea
1878:
1848:
1785:
1675:
1563:
1477:
835:
778:
1937:Leuckart & Rueppell, 1828"
1262:
1218:
1184:
1048:
1:
1730:. TFH Publications. pp.
1571:"Introduction to the Echiura"
1064:Acta Palaeontologica Polonica
1042:
958:Fisher & Macginitie, 1928
594:In the 1970s, the spoon worm
285:. Once treated as a separate
2101:10.1371/journal.pone.0056809
1974:van der Land, Jacob (2004).
1842:10.1016/0272-7714(86)90020-X
1511:10.1371/journal.pone.0120002
627:
7:
2053:10.1016/j.ympev.2016.03.003
2027:Goto, Ryutaro (June 2016).
1573:. UC Museum of Paleontology
1361:10.1016/j.ympev.2008.07.008
711:the net and eaten by other
349:, in the now defunct class
10:
2523:
2166:. CRC Press. p. 232.
1935:Ochetostoma erythrogrammon
1657:Barnes, Robert D. (1982).
991:Ochetostoma erythrogrammon
949:Forbes & Goodsir, 1841
847:at a market in South Korea
736:Ochetostoma erythrogrammon
675:Spoon worms are typically
537:Ochetostoma erythrogrammon
413:
2286:
2217:Tanaka, Masaatsu (2017).
2187:Tanaka, Masaatsu (2017).
1758:Felty Light, Sol (1954).
1191:Tanaka, Masaatsu (2017).
1171:10.11646/zootaxa.3148.1.3
1120:Tanaka, Masaatsu (2017).
206:
201:
119:Scientific classification
117:
108:
99:
23:
2010:California Fish and Game
1724:Walls, Jerry G. (1982).
1439:BMC Evolutionary Biology
791:are associated with the
708:peristaltic contractions
527:Distribution and habitat
1871:Encyclopædia Britannica
1856:Shipley, Arthur Everett
385:Mazon Creek fossil beds
380:Coprinoscolex ellogimus
278:, are a small group of
2136:Echinoderm Aquaculture
2004:Tallent, L.G. (1976).
1931:Chuang, S. H. (1962).
1452:10.1186/1471-2148-7-57
1076:10.4202/app.01107.2023
848:
672:
659:
540:
321:Taxonomy and evolution
267:
2507:Protostome subclasses
2441:Paleobiology Database
2139:. Wiley. p. 60.
1885:Cowles, Dave (2005).
1150:Zhang, Z.-Q. (2011).
974:A worm of the family
914:Lacaze-Duthiers, 1858
843:
665:
657:
534:
491:are connected to the
263:
2258:at Wikimedia Commons
1816:Listriolobus pelodes
1682:Toonen, Rob (2012).
1659:Invertebrate Zoology
616:with a more diverse
597:Listriolobus pelodes
476:Listriolobus pelodes
389:Middle Pennsylvanian
309:from the sea floor.
2092:2013PLoSO...856809G
2045:2016MolPE..99..247G
1941:Biological Bulletin
1861:"Echiuroidea"
1834:1986ECSS...22....1S
1502:2015PLoSO..1020002T
1404:10.1038/nature09864
1396:2011Natur.471...95S
1318:10.1038/nature06614
1310:2008Natur.452..745D
1273:. Online Zoologists
853:fat innkeeper worms
1794:Thalassema mellita
1031:Urechis unicinctus
857:Urechis unicinctus
849:
750:suspension feeders
673:
660:
584:Lissomyema mellita
541:
403:Llwygarua suzannae
333:Peter Simon Pallas
268:
30:Darriwilian–Recent
2479:
2478:
2280:Taxon identifiers
2254:Media related to
2173:978-1-351-64369-6
2146:978-1-119-00585-8
1889:Echiurus echiurus
1694:on 26 August 2012
1614:978-81-315-0104-7
1304:(7188): 745–749.
1294:Haddock, S. H. D.
1195:Echiurus echiurus
1011:Arhynchite hayaoi
959:
950:
941:
940:Quatrefages, 1847
924:
915:
895:According to the
830:sexual dimorphism
648:Echiurus echiurus
602:continental shelf
600:was found on the
555:(e.g. the genera
406:was found in the
328:Echiurus echiurus
315:Middle Ordovician
258:
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2266:Data related to
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1778:
1755:
1746:
1745:
1721:
1704:
1703:
1701:
1699:
1690:. Archived from
1679:
1673:
1672:
1654:
1633:
1632:
1626:
1618:
1600:
1583:
1582:
1580:
1578:
1567:
1561:
1560:
1540:
1534:
1533:
1523:
1513:
1481:
1475:
1474:
1464:
1454:
1430:
1424:
1423:
1379:
1373:
1372:
1344:
1338:
1337:
1289:
1283:
1282:
1280:
1278:
1271:"Phylum Echiura"
1266:
1260:
1259:
1257:
1256:
1250:
1244:. Archived from
1235:
1229:Ottoia prolifica
1222:
1216:
1215:
1213:
1211:
1188:
1182:
1181:
1179:
1156:
1147:
1141:
1140:
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1117:
1108:
1107:
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1103:
1089:
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1079:
1061:
1052:
1026:
1006:
986:
971:
957:
948:
939:
922:
913:
891:List of families
817:Bonellia viridis
668:Bonellia viridis
638:, can leave the
449:Ikeda taenioides
421:Ikeda taenioides
195:
127:
126:
104:
94:
31:
27:Temporal range:
21:
20:
2522:
2521:
2517:
2516:
2515:
2513:
2512:
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2482:
2481:
2480:
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2416:
2408:
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2395:
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2382:
2377:
2369:
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2356:
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2343:
2338:
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2325:
2316:
2315:
2310:
2301:
2300:
2295:
2282:
2246:
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2231:
2229:
2215:
2211:
2201:
2199:
2185:
2181:
2174:
2158:
2154:
2147:
2131:
2127:
2072:
2068:
2025:
2021:
2002:
1998:
1988:
1986:
1972:
1968:
1953:10.2307/1539504
1929:
1925:
1917:
1913:
1903:
1901:
1883:
1879:
1853:
1849:
1812:
1805:
1790:
1786:
1776:
1774:
1772:
1756:
1749:
1742:
1722:
1707:
1697:
1695:
1680:
1676:
1669:
1655:
1636:
1620:
1619:
1615:
1601:
1586:
1576:
1574:
1569:
1568:
1564:
1541:
1537:
1496:(3): e0120002.
1482:
1478:
1431:
1427:
1390:(7336): 95–98.
1380:
1376:
1345:
1341:
1290:
1286:
1276:
1274:
1267:
1263:
1254:
1252:
1248:
1233:
1223:
1219:
1209:
1207:
1197:(Pallas, 1766)"
1189:
1185:
1177:
1154:
1148:
1144:
1134:
1132:
1118:
1111:
1101:
1099:
1091:
1090:
1083:
1059:
1053:
1049:
1045:
1038:
1027:
1018:
1016:Thalassematidae
1007:
998:
987:
978:
972:
946:Thalassematidae
893:
875:, dressed with
859:) are known as
838:
781:
682:A worm such as
630:
551:or the shallow
549:intertidal zone
529:
416:
323:
243:Thalassematidae
194:
169:Pleistoannelida
121:
95:
93:
92:
87:
82:
77:
72:
67:
62:
57:
52:
47:
42:
37:
29:
28:
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17:
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2477:
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2474:
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2450:
2437:
2427:
2414:
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2388:
2375:
2362:
2349:
2336:
2323:
2308:
2292:
2290:
2284:
2283:
2272:
2271:
2270:at Wikispecies
2259:
2245:
2244:External links
2242:
2240:
2239:
2209:
2179:
2172:
2152:
2145:
2125:
2066:
2019:
1996:
1966:
1923:
1911:
1877:
1866:Chisholm, Hugh
1847:
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837:
834:
824:properties of
783:Echiurans are
780:
777:
769:innkeeper worm
704:filter feeders
629:
626:
528:
525:
516:coelomic fluid
415:
412:
394:burrow fossils
325:The spoonworm
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2086:(2): e56809.
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2034:
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2016:(4): 286–298.
2015:
2011:
2007:
2000:
1985:
1981:
1977:
1976:"Echiuroidea"
1970:
1962:
1958:
1954:
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1895:Fisher, 1946"
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1771:9780520007505
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1741:0-86622-141-7
1737:
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1668:0-03-056747-5
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1272:
1265:
1251:on 2012-03-12
1247:
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819:
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812:
809:
804:
800:
798:
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790:
786:
776:
774:
773:Urechis caupo
770:
766:
765:leopard shark
762:
758:
753:
751:
747:
743:
738:
737:
732:
730:
726:
722:
718:
714:
713:invertebrates
709:
705:
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700:
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693:
689:
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566:
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560:
559:
554:
550:
546:
539:
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524:
521:
520:metanephridia
517:
513:
509:
504:
502:
498:
494:
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485:
480:
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468:
463:
461:
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450:
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429:
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423:
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411:
410:lagerstätte.
409:
405:
404:
399:
395:
390:
386:
382:
381:
375:
373:
369:
364:
362:
361:
360:Urechis caupo
356:
352:
348:
344:
340:
339:
334:
330:
329:
318:
316:
312:
308:
303:
300:
296:
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147:
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141:
140:
137:
134:
131:
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125:
120:
116:
113:
112:
111:Urechis caupo
107:
103:
98:
91:
86:
81:
76:
71:
66:
61:
56:
51:
46:
41:
36:
22:
19:
2287:
2230:. Retrieved
2222:
2212:
2200:. Retrieved
2192:
2189:"Bonelliida"
2182:
2162:
2155:
2135:
2128:
2083:
2079:
2069:
2036:
2032:
2022:
2013:
2009:
1999:
1987:. Retrieved
1979:
1969:
1947:(1): 80–85.
1944:
1940:
1934:
1926:
1914:
1902:. Retrieved
1898:
1892:
1888:
1880:
1869:
1850:
1825:
1819:
1815:
1800:: 1884–1887.
1797:
1793:
1787:
1775:. Retrieved
1760:
1726:
1696:. Retrieved
1692:the original
1687:
1677:
1658:
1604:
1575:. Retrieved
1565:
1548:
1544:
1538:
1493:
1489:
1479:
1442:
1438:
1428:
1387:
1383:
1377:
1355:(1): 23–31.
1352:
1348:
1342:
1301:
1297:
1287:
1275:. Retrieved
1264:
1253:. Retrieved
1246:the original
1241:
1237:
1228:
1220:
1208:. Retrieved
1200:
1194:
1186:
1162:
1158:
1145:
1133:. Retrieved
1125:
1100:. Retrieved
1096:
1093:"Spoon Worm"
1067:
1063:
1050:
1029:
1009:
989:
894:
884:
865:sea cucumber
860:
856:
850:
836:Culinary Use
815:
814:The species
813:
805:
801:
782:
779:Reproduction
772:
754:
734:
733:
727:and often a
697:
696:
683:
681:
677:detritivores
674:
666:
646:
644:
633:
631:
595:
593:
589:sand dollars
582:
568:
562:
556:
542:
535:
507:
505:
481:
474:
470:
464:
453:
447:
436:peanut worms
425:
419:
417:
401:
378:
376:
372:Capitellidae
365:
358:
355:holothurians
336:
326:
324:
304:
275:
271:
269:
264:
202:Subdivision
191:
175:
162:
109:
18:
2379:iNaturalist
2312:Wikispecies
2219:"Echiurida"
2039:: 247–260.
1989:30 November
1904:18 February
1891:subspecies
1828:(1): 1–17.
1777:30 November
1698:10 November
1277:17 February
1210:17 February
1135:17 February
976:Bonelliidae
911:Bonelliidae
885:gaebul-jeot
877:chili sauce
845:Spoon worms
808:trochophore
717:commensally
606:Los Angeles
579:Bonelliidae
512:haemoglobin
489:diverticula
408:Castle Bank
276:spoon worms
217:Bonelliidae
196:Newby, 1940
2486:Categories
1551:(4): 317.
1255:2019-02-17
1043:References
996:Echiuridae
937:Echiuridae
923:Bock, 1942
905:Bonelliida
873:sea urchin
869:sea squirt
822:antibiotic
793:peritoneal
761:autotomise
746:scavengers
725:scale worm
444:prostomium
440:homologous
427:Lissomyema
347:Priapulida
237:Echiuridae
211:Bonelliida
188:Subclass:
182:Sedentaria
2492:Echiurans
1893:alaskanus
1623:cite book
1122:"Echiura"
1036:Urechidae
1034:, family
1014:, family
994:, family
955:Urechidae
931:Echiurida
929:suborder
903:suborder
881:soy sauce
785:dioecious
757:predation
699:Urechidae
640:substrate
628:Behaviour
614:ecosystem
432:proboscis
383:from the
343:Sipuncula
338:Lumbricus
299:proboscis
249:Urechidae
231:Echiurida
142:Kingdom:
136:Eukaryota
2497:Annelids
2297:Wikidata
2120:23457618
2080:PLOS ONE
2061:26975690
1858:(1911).
1530:25734664
1490:PLOS ONE
1471:17411434
1412:21368831
1369:18692145
1326:18322464
1175:Archived
1165:: 7–12.
920:Ikedidae
826:bonellin
684:Echiurus
671:, female
635:Echiurus
622:polluted
558:Echiurus
553:subtidal
545:infaunal
497:ciliated
471:Echiurus
455:Bonellia
398:Cambrian
351:Gephyrea
307:detritus
295:segments
291:Annelida
265:Echiurus
223:Ikedidae
156:Annelida
152:Phylum:
146:Animalia
132:Domain:
2456:8275134
2371:7062236
2345:Echiura
2332:Echiura
2318:Echiura
2288:Echiura
2268:Echiura
2256:Echiura
2232:9 March
2202:9 March
2111:3572977
2088:Bibcode
2041:Bibcode
1961:1539504
1868:(ed.).
1830:Bibcode
1732:262–267
1577:7 March
1545:Lethaia
1521:4348511
1498:Bibcode
1462:1855331
1420:4428998
1392:Bibcode
1334:4397099
1306:Bibcode
1159:Zootaxa
1102:9 March
953:family
944:family
935:family
918:family
909:family
797:gametes
715:living
575:abyssal
564:Urechis
508:Urechis
460:cloacal
442:to the
414:Anatomy
368:annelid
311:Fossils
283:animals
272:Echiura
247:Family
241:Family
235:Family
221:Family
215:Family
192:Echiura
24:Echiura
2453:uBio:
2430:NZOR:
2410:914211
2384:117589
2303:Q64119
2170:
2143:
2118:
2108:
2059:
1959:
1768:
1738:
1665:
1611:
1528:
1518:
1469:
1459:
1445:: 57.
1418:
1410:
1384:Nature
1367:
1332:
1324:
1298:Nature
861:gaebul
789:gonads
688:mucous
624:area.
610:sewage
567:, and
501:septum
493:rectum
484:coelom
287:phylum
280:marine
229:Order
209:Order
2464:WoRMS
2446:67169
2392:IRMNG
2223:WoRMS
2193:WoRMS
1980:WoRMS
1957:JSTOR
1920:Japan
1864:. In
1416:S2CID
1330:S2CID
1249:(PDF)
1234:(PDF)
1201:WoRMS
1178:(PDF)
1155:(PDF)
1126:WoRMS
1060:(PDF)
742:tests
692:cilia
618:fauna
570:Ikeda
467:setae
274:, or
176:Clade
163:Clade
2469:1269
2423:6427
2418:NCBI
2405:ITIS
2397:1387
2366:GBIF
2358:8847
2234:2019
2204:2019
2168:ISBN
2141:ISBN
2116:PMID
2057:PMID
1991:2011
1906:2019
1779:2011
1766:ISBN
1736:ISBN
1700:2012
1663:ISBN
1629:link
1609:ISBN
1579:2019
1526:PMID
1467:PMID
1408:PMID
1365:PMID
1322:PMID
1279:2019
1212:2019
1163:3148
1137:2019
1104:2019
879:and
871:and
729:fish
723:, a
721:crab
604:off
345:and
270:The
35:PreꞒ
2353:EoL
2340:AFD
2327:ADW
2106:PMC
2096:doi
2049:doi
1949:doi
1945:123
1838:doi
1796:".
1553:doi
1516:PMC
1506:doi
1457:PMC
1447:doi
1400:doi
1388:471
1357:doi
1314:doi
1302:452
1167:doi
1072:doi
2488::
2466::
2443::
2420::
2407::
2394::
2381::
2368::
2355::
2342::
2329::
2314::
2299::
2225:.
2221:.
2195:.
2191:.
2114:.
2104:.
2094:.
2082:.
2078:.
2055:.
2047:.
2037:99
2035:.
2031:.
2014:62
2012:.
2008:.
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