25:
508:
populations have more haplotype diversity than all four of the North
Atlantic populations, which indicates that the North Atlantic population is more recently established than the Pacific population. The minimum estimated age of the New Brunswick population is between 47 and 143 thousand years old. Including the Massachusetts population, this number is between 82 and 150 thousand years, but Iceland has the oldest estimated population with the minimum age ranging from 68 to 204 thousand years old.
108:
95:
466:. Food is caught with the tentacles, then directed to the manubrium; sometimes food lands directly onto the manubrium and is consumed that way. The food is then distributed through a canal system, consisting of four radial canals and an outer ring. Defense and the capture of prey are helped by unique stinging cells called
507:
than the New
Brunswick population. The more recent expansion of these haplotypes demonstrates the southward movement of hydroid populations, possibly due to climate change. The North Atlantic populations contain ancestral haplotypes, which differ from the populations in Japan and New Zealand. Pacific
387:
The planulae are free-swimming for a while but eventually attach themselves to some solid surface, where they begin their reproductive phase of life. Once attached to a substrate, a planula quickly develops into one feeding polyp. As the polyp grows, it begins developing branches of other feeding
452:
starts and later becomes intracellular. They have incomplete digestive tracts where the food enters, is digested, and expelled through the same opening. Scientists are trying to pinpoint their food preferences, but experiments have shown Obelia feeding on crustaceans under lab conditions, and
336:
have medusa buds. These medusa buds differentiate Obelia from others in the family
Campanulariidae because development begins from a bud within the gonotheca. Eventually the buds are lost, and subsequent development shares resemblances with other hydranths. Other hydranths are specialized for
518:
from their size in length and diameter, as well as their smaller hydrothecal cusps and relatively thinner perisarc thickness. Some morphological traits are hard to distinguish across species, so observing a combination of these traits will help with identification. Other useful observable
461:
and microplanktonic sex through grazers. During the polyp stage, the mouth is situated at the top of the body, surrounded by tentacles, whereas during the medusa stage, the mouth is situated at the distal end of the main body structure. Four gonads lie in this main body structure, or
494:
was first documented in these areas in the 1990s but were later found in
Massachusetts and Japan in the 2000s. There are three reciprocally monophyletic clades of Obelia, one branch for the North Atlantic, one for Japan, and one for New Zealand. There seems to be an ancestral
264:, which are aquatic (mainly marine) organisms that are relatively simple in structure with a diameter around 1mm. There are currently 120 known species, with more to be discovered. These species are grouped into three broad categories:
617:
Boero, Ferdinando; Bucci, Cecilia; Colucci, Anna Maria
Rosaria; Gravili, Cinzia; Stabili, Loredana (10 September 2007). "Obelia (Cnidaria, Hydrozoa, Campanulariidae): a microphagous, filter-feeding medusa: Feeding of Obelia medusae".
812:
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characteristics are branching pattern of colonies and length of trophosome. There are variations and exceptions to these, which makes identification even more difficult.
304:
are usually found no deeper than 200 metres (660 ft) from the water's surface, growing in intertidal rock pools and at the extreme low water of spring tides.
214:
348:
The next generation of the life cycle begins when the medusae are released from the gonozooids, producing free swimming male only medusae velum with
1065:
866:
680:
Cornelius, P.F.S., 1995b. North-West
European thecate hydroids and their Medusae. Part 2. Synopses of the British Fauna (New Series), No 50.
671:
Cornelius, P.F.S., 1990a. European Obelia (Cnidaria, Hydroida): systematics and identification. Journal of
Natural History 24: 535-578.
861:
527:
have longer first and second order branches, in addition to a greater variation in hydrothecal cusp length than others in the genus.
1013:
1039:
478:. It has a ridge-like structure on the inner margin, called a velum. If the velum is present, it is called a craspedote medusa.
1044:
1152:
356:. The physical appearance of the male and female medusae velum, including their gonads, are indistinguishable, and the
696:
332:, which can be found expanded or contracted, to aid in the growth of this organism by feeding. The reproductive polyp
828:
794:
725:"When morphometry meets taxonomy: morphological variation and species boundaries in Proboscoida (Cnidaria: Hydrozoa)"
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68:
46:
992:
39:
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When morphometry meets taxonomy: morphological variation and species boundaries in
Proboscoida (Cnidaria:Hydrozoa),
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was later accepted as a legitimate species, but taxonomy regarding the entire genus is debated over.
1142:
107:
33:
877:
50:
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Some taxonomic information also came from
National Center for Biotechnology Information (NCBI)
531:
differs from the previous species due to their more cylindrical and longer hydrothecal cusps.
445:
1093:
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that occurs in the North
Atlantic populations from Massachusetts, New Brunswick, and Iceland
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909:
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313:
697:"Mitochondrial evolution and phylogeography in the hydrozoan Obelia geniculata (Cnidaria)"
8:
839:
Mitochondrial evolution and phylogeography in the hydrozoan Obelia geniculata (Cnidaria),
417:
369:
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can only be determined by observing the inside of the gonads, which will either contain
594:
296:
has a worldwide distribution except the high-Arctic and Antarctic seas. and a stage of
102:
1088:
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221:
207:
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Obelia (Cnidaria, Hydrozoa, Campanulariidae): a microphagous, filter-feeding medusa,
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953:
764:
736:
627:
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574:
555:"Prey capture by the cosmopolitan hydromedusae, Obelia spp., in the viscous regime"
487:
409:
254:
242:
200:
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Prey capture by the cosmopolitan hydromedusae, Obelia spp. in the viscous regime,
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is characterized by a thicker perisarc with more variation that other species of
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Estimates of divergence times and distinctive haplotypes provide evidence of
94:
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421:
413:
159:
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329:
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425:
238:
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species are common in coastal and offshore plankton around the world.
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467:
458:
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119:
871:
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Marine Life: An Illustrated Encyclopedia of Invertebrates in the Sea
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Cunha, Amanda; Collins, Allen; Marques, Antonio (20 November 2019).
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filling the area between the two true tissue layers. They carry a
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Govindarajan, AF; Halanych, KM; Cunningham, CW (17 August 2004).
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individuals, thus forming a new generation of polyps by asexual
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defense. The main stalky body of the colony is composed of a
771:
Grzimek's Animal Life Encyclopedia (Volume 1: Lower Animals)
759:
F. Boero, C. Bucci, A.M.R. Colucci, C. Gravili, L. Stabili;
365:
357:
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around Iceland and southeastern Canada. In one study,
372:, releasing sperm and eggs that fertilize to form a
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stages in their life cycle. Hydrozoa belongs to the
722:
690:
688:
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324:surfaces. In mature colonies there are individual
804:Association of Limnology and Oceanography, 2016.
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546:
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1134:
783:E.P Solomon, L.R Berg, and D.W Martin (editor);
765:https://doi.org/10.1111/j.1439-0485.2007.00164.x
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837:AF. Govindarajan, KM Halanych, CW Cunningham;
541:
503:The population from Woods Hole, MA shows less
718:
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245:of mainly marine and some freshwater animal
848:Zoological Journal of the Linnean Society.
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457:. Some species of Obelia are known ingest
552:
380:, then a ciliated swimming larva called a
93:
850:https://doi.org/10.1093/zoolinnean/zlz166
740:
729:Zoological Journal of the Linnean Society
713:
605:
588:
578:
69:Learn how and when to remove this message
651:. Rastogi Publications. pp. 1–118.
32:This article includes a list of general
1135:
553:Sutherland, Kelly (10 November 2016).
876:
875:
1107:3F6387A9-FF46-E2E2-85D8-FE9FDEB5668C
1081:e31a8b48-c35e-46f6-a9a4-6c6330f3767c
1006:7d41c328-e56f-4226-adc0-36e40403c013
813:An Introduction to the Invertebrates
18:
514:are distinguishable from others in
341:, which is covered by a protective
13:
844:A. Cunha, A. Collins, A. Marques;
823:; The McGraw-Hill Companies, Inc;
38:it lacks sufficient corresponding
14:
1164:
855:
806:https://doi.org/10.1002/lno.10390
780:; Wiley-Interscience Publication.
416:, with two true tissue layers—an
773:; Van Nostrand Reinhold Company.
632:10.1111/j.1439-0485.2007.00164.x
106:
23:
797:(6th edition, hardcover, 2002).
674:
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1:
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316:. During this stage of life,
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862:A Hydroid: Obelia Longissima
816:; Cambridge University Press
648:Genetics Classical To Modern
481:
395:
376:, which later morphs into a
312:The polyp colony reproduces
7:
10:
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559:Limnology and Oceanography
1153:Bioluminescent cnidarians
884:
867:The Double Life of Obelia
821:Zoology Laboratory Manual
742:10.1093/zoolinnean/zlz166
196:
191:
103:Scientific classification
101:
92:
85:
789:; Thomson Learning Inc;
534:
400:Through its life cycle,
368:. The medusae reproduce
186:Peron and Lesueur, 1810
53:more precise citations.
763:Web of Science, 2007.
525:Obelia. O. longissima
448:is present where the
446:gastrovascular cavity
1001:Fauna Europaea (new)
645:P. K. Gupta (2007).
428:)—with a jelly-like
831:(4th edition, 1999)
810:J. Moore (editor);
571:2016LimOc..61.2309S
420:(ectodermis) and a
404:take on two forms:
16:Genus of hydrozoans
1130:
1129:
1089:Open Tree of Life
878:Taxon identifiers
580:10.1002/lno.10390
505:genetic diversity
474:triggered by the
266:O. bidentata
230:
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222:Obelia longissima
208:Obelia geniculata
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79:
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1148:Cnidarian genera
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565:(6): 2309–2317.
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215:Obelia bidentata
201:Obelia dichotoma
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703:. Retrieved
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529:O. bidentata
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1027:iNaturalist
776:D. George;
626:: 178–183.
472:nematocysts
412:. They are
51:introducing
1137:Categories
754:References
705:7 November
468:cnidocytes
459:tintinnids
426:endodermis
334:gonozooids
308:Life cycle
239:hydrozoans
34:references
590:1912/8594
497:haplotype
482:Phylogeny
464:manubrium
450:digestion
418:epidermis
396:Structure
354:tentacles
339:coenosarc
326:hydranths
322:substrate
314:asexually
126:Kingdom:
120:Eukaryota
59:June 2013
967:46551829
895:Wikidata
599:89441197
476:cnidocil
455:ciliates
430:mesoglea
378:blastula
370:sexually
343:perisarc
262:Cnidaria
192:Species
166:Family:
150:Hydrozoa
140:Cnidaria
136:Phylum:
130:Animalia
116:Domain:
1019:2268142
901:Q134802
786:Biology
567:Bibcode
442:ganglia
390:budding
382:planula
328:called
288:sea fur
247:species
176:Genus:
156:Order:
146:Class:
47:improve
1120:117034
1094:329822
1078:NZOR:
993:240596
980:1OBELG
928:Obelia
915:Obelia
886:Obelia
827:
793:
655:
597:
512:Obelia
410:medusa
402:Obelia
374:zygote
350:gonads
318:Obelia
302:Obelia
298:Obelia
294:Obelia
284:Obelia
272:, and
259:phylum
255:medusa
234:Obelia
181:Obelia
87:Obelia
36:, but
1115:WoRMS
1102:Plazi
1071:32569
1045:49514
1032:49536
954:7PMT9
941:27176
841:2004.
700:(PDF)
595:S2CID
535:Notes
438:brain
434:nerve
406:polyp
362:sperm
251:polyp
243:class
1066:NCBI
1040:ITIS
1014:GBIF
975:EPPO
936:BOLD
825:ISBN
791:ISBN
707:2022
653:ISBN
444:. A
408:and
366:eggs
253:and
241:, a
1053:NBN
962:EoL
949:CoL
923:AFD
910:ADW
737:doi
733:190
628:doi
585:hdl
575:doi
440:or
364:or
358:sex
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Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
