Bathynomus giganteus

2025-10-31T13:48:05Z

168.30.14.75:

{{Short description|Species of crustacean}}
{{Use dmy dates|date=October 2018}}
{{Speciesbox
| fossil_range = [[Holocene]] to recent<ref>{{Cite web |url=https://www.marinespecies.org/aphia.php?p=taxdetails&id=259252 |title=WoRMS - World Register of Marine Species - Bathynomus giganteus A. Milne-Edwards, 1879}}</ref>
| image = Bathynomus giganteus as seen by remotely operated vehicle (ROV) Deep Discoverer at a depth of 816 meters at South Reed, Gulf of Mexico, 2017-11-30.webm
| image_caption = ''Bathynomus giganteus'' at a depth of {{circa|800 m}}
| image2 = giant isopod.jpg
| image2_caption = The underside of ''Bathynomus giganteus''
| taxon = Bathynomus giganteus
| authority = [[Alphonse Milne-Edwards|A. Milne-Edwards]], 1879
}}

'''''Bathynomus giganteus''''' is a [[species]] of aquatic [[crustacean]], of the order [[Isopoda]]. It is a member of the '''[[giant isopod]]s '''(''Bathynomus''), and as such it is related—albeit distantly—to [[shrimp]]s and [[crab]]s.<ref name=":0">{{Cite web |url=http://seapics.com/feature-subject/marine-invertebrates/giant-isopod-pictures.html |title=Giant Isopod {{!}} Bathynomus giganteus {{!}} SeaPics.com |website=seapics.com |access-date=2019-01-17}}</ref> It was the first ''[[Giant isopod|Bathynomus]]'' species ever documented and was described in 1879 by French zoologist [[Alphonse Milne-Edwards|Alphonse Milne Edwards]] after the isopod was found in fishermen's nets off the coast of the [[Dry Tortugas]] in the [[Gulf of Mexico]].<ref name=":1">{{cite journal |last1=Briones-Fourzán |first1=Patricia |last2=Lozano-Alvarez |first2=Enrique |title=Aspects of the biology of the giant isopod ''Bathynomus giganteus'' A. Milne Edwards, 1879 (Flabellifera: Cirolanidae), off the Yucatan Peninsula |journal=Journal of Crustacean Biology |date=1 July 1991 |volume=11 |issue=3 |pages=375–385 |doi=10.2307/1548464 |jstor=1548464 |doi-access=free }}</ref>

The ''Bathynomus'' genus is [[benthic]] and abundant in cold waters with a depth of 310–2140 m in the West-Atlantic, including the [[Gulf of Mexico]] and the [[Caribbean Sea|Caribbean]]. It was the first species of ''Bathynomus'' to be [[Species description|described]] and historically it was reported from other oceans, but these are now recognized as other closely related species.<ref name=LowryDempsey2006>{{cite book |author1=Lowry, J. K. |author2=Dempsey, K. |year=2006 |chapter=The giant deep-sea scavenger genus ''Bathynomus'' (Crustacea, Isopoda, Cirolanidae) in the Indo-West Pacific |editor1=Richer de Forges, B. |editor2=Justone, J.-L. |title=Tropical Deep-Sea Benthos |volume=24 |pages=163–193 |publisher=Mémoires du Muséum national d'Histoire naturelle }}</ref><ref name=Shipley2016>{{cite journal |author1=Shipley, O. |author2=Bruce, N. L. |author3=Violich, M. |author4=Baco, A. |author5=Rawlins, S. |author6=Brooks, E. J. |year=2016 |title=A new species of ''Bathynomus'' Milne Edwards, 1879 (Isopoda: Cirolanidae) from The Bahamas, Western Atlantic |journal=Zootaxa |volume=4147 |issue=1 |pages=82–88 |doi=10.11646/zootaxa.4147.1.6 |pmid=27515606 }}</ref> The unusually large size of ''Bathynomus'' has been attributed to an effect called [[deep-sea gigantism]], where invertebrates living in cold deep waters tend to grow larger and have longer lifespans.<ref>{{Cite web |url=https://scienceblogs.com/deepseanews/2007/04/04/why-is-the-giant-isopod-giant |title=Why is The Giant Isopod Giant? {{!}} ScienceBlogs |last=McClain |first=C. R. |date=4 April 2007 |website=scienceblogs.com |access-date=2019-01-17}}</ref><ref>{{Cite journal |last=Timofeev |first=S. F. |date=November 2001 |title=Bergmann's Principle and Deep-Water Gigantism in Marine Crustaceans |url=https://www.researchgate.net/publication/7816370 |journal=Izvestiia Akademii Nauk. Seriia Biologicheskaia |volume=28 |issue=6 |pages=764–768}}</ref>

==Physical description==
[[File:Bathynomus giganteus.jpg|thumb|left|A frontal view of ''Bathynomus giganteus'', showing its large, highly reflective compound eyes]]
Like most [[crustacean]]s, the body of ''Bathynomus giganteus'' is divided into three distinct regions; a head ([[Cephalon (arthropod head)|cephalon]]), a [[thorax]], and an abdomen ([[pleon]]).<ref name=":1" /> They have large triangular [[compound eye]]s that are spaced very far apart and have over 4000 individual facets.<ref name=":2">{{Cite journal |last1=Chamberlain |first1=Steven |last2=Meyer-Rochow |first2=Victor |date=1986 |title=Morphology of the compound eye of the giant deep-sea isopod ''Bathynomus giganteus'' |journal=Journal of Morphology |volume=189 |issue=2 |pages=145–156 |doi=10.1002/jmor.1051890205 |pmid=3746916 |s2cid=37070286 }}</ref> When light bounces off a highly-reflective layer called the [[tapetum lucidum]] at the back of their eyes, it makes them appear to glow.<ref name=":2" /> ''B. giganteus'' reaches a typical length between 19 and 36 cm<ref name="briones">{{cite journal |last1=Briones-Fourzán |first1=Patricia |last2=Lozano-Alvarez |first2=Enrique |title=Aspects of the biology of the giant isopod ''Bathynomus giganteus'' A. Milne Edwards, 1879 (Flabellifera: Cirolanidae), off the Yucatan Peninsula |journal=Journal of Crustacean Biology |date=1 July 1991 |volume=11 |issue=3 |pages=375–385 |doi=10.2307/1548464 |jstor=1548464 |doi-access=free }}</ref> an individual claimed to be 76 cm long has been reported by the popular press, but the largest confirmed was ca. 50 cm.<ref name="McClain">{{cite journal |last1=McClain |first1=Craig R. |last2=Balk |first2=Meghan A. |last3=Benfield |first3=Mark C. |last4=Branch |first4=Trevor A. |last5=Chen |first5=Catherine |last6=Cosgrove |first6=James |last7=Dove |first7=Alistair D.M. |last8=Gaskins |first8=Lindsay C. |last9=Helm |first9=Rebecca R. |last10=Hochberg |first10=Frederick G. |last11=Lee |first11=Frank B. |last12=Marshall |first12=Andrea |last13=McMurray |first13=Steven E. |last14=Schanche |first14=Caroline |last15=Stone |first15=Shane N. |last16=Thaler |first16=Andrew D. |title=Sizing ocean giants: patterns of intraspecific size variation in marine megafauna |journal=PeerJ |date=13 January 2015 |volume=3 |pages=e715 |doi=10.7717/peerj.715 |pmid=25649000 |pmc=4304853 |doi-access=free }}</ref>

==Reproduction==
''Bathynomus'' reproduce via egg-laying. Mature females develop a pouch known as a [[Brood pouch (Peracarida)|marsupium]], where the eggs are stored until the young are ready to emerge as miniatures of the adults, known as [[manca]], completely bypassing a larval stage.<ref>{{Cite book|url=https://books.google.com/books?id=FweHI7uZ198C&pg=PA174|title=Multicellular Animals: The Phylogenetic System of the Metazoa|last=Ax|first=Peter|date=2000-08-28|publisher=Springer Science & Business Media|isbn=9783540674061|language=en}}</ref> Mancae can reach lengths up to 60 mm and are characterized by their lack of the seventh pair of [[pereiopod]]s.<ref name=":1" /> The reproductive anatomy of ''Bathynomus giganteus'' resembles that of other isopods.<ref name=":3">{{Cite journal |last1=Perry |first1=Noretta |last2=Hinsch |first2=Gertrude |date=1991 |title=Reproduction in the giant isopod, ''Bathynomus giganteus'' |doi=10.1080/07924259.1991.9672192 |journal=Invertebrate Reproduction & Development|volume=20 |issue=2 |pages=153–157 }}</ref> The females of ''B. giganteus'', while being so many times larger than females of other isopods, carries approximately the same number of eggs in its marsupium.<ref name=":3" /> The eggs, however, show an increase in size which appears to be almost proportional to the increase in body size.<ref name=":3" /> The reproductive organs of the males also resemble those of the males of smaller isopod species.<ref name=":3" />

==Ecology==
As scavengers, ''Bathynomus giganteus'' plays a crucial role in the deep-sea ecosystem. They feed on the remains of dead marine organisms that sink to the ocean floor, helping to recycle nutrients back into the ecosystem. This scavenging behavior is vital for maintaining the balance of deep-sea communities.<ref>{{Cite journal |last1=Rogers |first1=Andrew D. |title=The Importance of Deep-Sea Scavengers |journal=Science |date=2023 |volume=368 |issue=6488 |pages=18-19 |doi=10.1126/science.abc5645}}</ref>

== Aquaculture ==
[[File:Bathynomus giganteus specimin being held by Dr. Nguyen Thanh Son.jpg|thumb|209x209px|2.62kg specimen found in [[Hanoi]]]]
Giant isopods are not usually [[Commercial fishing|fished commercially]]. However, other ''Bathynomus'' species can be found in the occasional oceanside restaurant in northern Taiwan, where they are boiled and typically served with rice.<ref name=":0"/>

== References ==
{{reflist|30em}}

{{Taxonbar|from=Q1366514}}
{{Portal bar|Crustaceans|Marine life}}

[[Category:Cymothoida]]
[[Category:Isopods of the Atlantic Ocean]]
[[Category:Crustaceans of Brazil]]
[[Category:Crustaceans described in 1879]]
[[Category:Taxa named by Alphonse Milne-Edwards]]

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Bathynomus giganteus