Swima
{{Short description|Genus of annelids}}
{{Automatic taxobox
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| taxon = Swima
| authority = Osborn, Haddock, Pleijel, Madin & Rouse, 2009
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Swima is a genus of marine polychaete worms found in the ocean at depths between {{convert|1,800|and|3,700|m|ft|abbr=off|sp=us}}.[https://www.seeker.com/bioluminescent-green-bombers-from-the-deep-sea-discovered-1764713643.html Bioluminescent 'Green Bombers' from the Deep Sea Discovered] Even if they are agile swimmers, they are often seen hanging immobile in the water column as they are neutrally buoyant.{{cite journal | url=https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1096-3642.2011.00727.x | doi=10.1111/j.1096-3642.2011.00727.x | title=Swima (Annelida, Acrocirridae), holopelagic worms from the deep Pacific | date=2011 | last1=Osborn | first1=Karen J. | last2=Haddock | first2=Steven H. D. | last3=Rouse | first3=Greg W. | journal=Zoological Journal of the Linnean Society | volume=163 | issue=3 | pages=663–678 }} This deep ocean pelagic (free-swimming) genus has modified bioluminescent gills that can be cast off from an individual. These discarded gills somewhat resemble green "bombs" that remain illuminated for several seconds after they have been discarded. It is thought that this is a defensive mechanism rather than reproductive, as it is seen in both mature and juvenile individuals. And because they are eyeless, communicating with light would be difficult.[https://www.nytimes.com/2009/08/25/science/25obbomb.html New Find in the Pacific: Worms With Glow Sticks] Swima worms are closely related to the recently discovered genus Teuthidodrilus, another pelagic cirratuliform of the bathyal zone.
Discovery
The first specimens of the genus Swima were discovered in the deep trenches of Monterey Bay, off the coast of California.
Taxonomy
There are currently three species recognised within the Swima:
- S. bombiviridis Osborn, Haddock, Pleijel, Madin & Rouse, 2009 (Green Bomber Worm or Bombardier Worm), Monterey Bay, California (type species)
- Swima fulgida Osborn, Haddock & Rouse, 2011 (Shining Bomber)
- Swima tawitawiensis Osborn, Haddock & Rouse, 2011 (Tawi-Tawi Bomber){{cite web|title=Swima tawitawiensis Osborn, Haddock & Rouse, 2011|url=http://www.marinespecies.org/aphia.php?p=taxdetails&id=587956|publisher=World Register of Marine Species|accessdate=6 February 2012}})
Anatomy and physiology
Animals of the Swima are characterized by a thick gelatinous sheath, transparent body, simple nuchal organs, a single medial subulate branchia, and four pair of small segmental branchiae modified as elliptical, bioluminescent sacs.
Etymology
The genus name, Swima, is derived from the Latin, referring to the animal's ability to swim.
References
{{Reflist|colwidth=30em|refs=
{{cite web|author=International Institute for Species Exploration|title=Bombardier Worm|work=Top 10 New Species – 2010|publisher=Arizona State University|location=Tempe, Arizona|year=2010|url=http://species.asu.edu/2010_species02|url-status=dead|archive-url=https://web.archive.org/web/20101228040356/http://species.asu.edu/2010_species02|archive-date=2010-12-28}}
{{cite news|author=Moskowitz C|title=Sea creature releases glowing decoy 'bombs'|publisher=LiveScience|year=2009|url=http://www.livescience.com/animals/090820-worm-defense.html|accessdate=2010-11-25}}
{{cite journal|vauthors=Osborn KJ, ((Haddock SHD)), Pleijel F, Madin LP, Rouse GW |title=Deep-sea, swimming worms with luminescent "bombs" |journal=Science|volume=325|issue=5943|pages=964|year=2009|doi=10.1126/science.1172488 |pmid=19696343|s2cid=206519310 }}
{{cite journal|vauthors=Osborn KJ, Rouse GW |title=Phylogenetics of Acrocirridae and Flabelligeridae|journal=Zoologica Scripta|volume=40|issue=2|pages=204–219|year=2010|doi=10.1111/j.1463-6409.2010.00460.x|s2cid=82620619 |url=https://repository.si.edu/bitstream/handle/10088/34432/OsbornRouse2010supp.pdf;https://repository.si.edu/bitstream/handle/10088/34432/OsbornRouse2010supp.pdf}}
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