Eunice aphroditois

{{Short description|Species of worm}} {{Redirect|Bobbit|other uses|Bobbitt}} {{Speciesbox |image = Eunice aphroditois.jpg |image_caption = A burrowed ''Eunice aphroditois'' |genus = Eunice |species = aphroditois |authority = Pallas, 1788 }}

'''''Eunice aphroditois''''' is a benthic bristle worm of warm marine waters. It lives mainly in the Atlantic Ocean, but can also be found in the Indo-Pacific.<ref name=giangrande2003/><ref name=worms/> It ranges in length from less than {{cvt|10|cm|in|0}} to nearly {{cvt|3|m|ft|0|abbr=}}.<ref name="extraordinary">{{Cite journal|last1=Kubota|first1=Shin|last2=Tanase|first2=Hidetomo|last3=Uchida|first3=Hiro'omi|date=March 2009|title=An extraordinarily large specimen of the polychaete worm Eunice aphroditois (Pallas) (Order Eunicea) from Shirahama, Wakayama, central Japan|url=https://repository.kulib.kyoto-u.ac.jp/dspace/handle/2433/179218|journal=Kuroshio Biosphere |volume=5 |pages=9–15 |issn=1349-2705}}</ref> Its exoskeleton displays a wide range of colors, from black to purple and more. This species is an ambush predator; it hunts by burrowing its whole body in soft sediment on the ocean floor and waiting until its antennae detect prey.<ref name=haag2016/> It then strikes with its sharp mandibles.<ref name=":3">{{Cite book|url=https://books.google.com/books?id=Rin4l7QZ1YEC&q=eunice+aphroditois&pg=PR3|title=Polychaetes & Allies: The Southern Synthesis|last=Study|first=Australian Biological Resources|date=2000|publisher=Csiro Publishing|isbn=978-0-643-06571-0|language=en}}</ref> It may also be found among coral reefs.

The species is called the '''sand striker'''<ref name=bbccormier/> or '''trap-jaw worm'''. Traces of their burrows have been found among fossils near Taiwan dating back 20 million years.<ref>Black, Riley, ''[https://www.nationalgeographic.com/science/2021/01/giant-predatory-worms-lurked-beneath-the-ancient-seafloor-fossils-reveal/ Giant predatory worms lurked beneath the ancient seafloor, fossils reveal]'', National Geographic, January 21, 2021</ref> A highly popularized name is '''bobbit worm'''<ref>{{Cite book|title=Coral Reef Animals of the Indo-Pacific|last=Goslinger|first=Terrence|publisher=Sea Challengers|year=1996|isbn=0-930118-21-9}}</ref><ref name=slb/> or '''bobbitt worm''',<ref name=bbccormier/> which is believed to derive from the John and Lorena Bobbitt case.<ref>{{cite book |title=Asia Pacific Reef Guide: Malaysia, Indonesia, Palau, Philippines, Tropical Japan, China, Vietnam, Thailand |first=Helmut |last=Debelius |publisher=IKAN |year=2001 |page=305 |isbn=978-3-925919-56-5 |url=https://books.google.com/books?id=ItUUAQAAIAAJ&q=lorena}}</ref>

==Description== thumb|Head with antennae These ambush predators have five antennae on their head that are used to sense prey.<ref>{{Cite journal|last1=Glasby|first1=Christopher J.|last2=Read|first2=Geoffrey B.|date=September 1998|title=A chronological review of polychaete taxonomy in New Zealand|journal=Journal of the Royal Society of New Zealand|volume=28|issue=3|pages=347–374|doi=10.1080/03014223.1998.9517570|issn=0303-6758|doi-access=free|bibcode=1998JRSNZ..28..347G }}</ref> The body is covered by a hard exoskeleton.<ref>{{Cite journal|last1=Paiva|first1=Paulo C.|last2=Fauchald|first2=Kristian|last3=Zanol|first3=Joana|date=2007-06-01|title=A phylogenetic analysis of the genus Eunice (Eunicidae, polychaete, Annelida)|journal=Zoological Journal of the Linnean Society|language=en|volume=150|issue=2|pages=413–434|doi=10.1111/j.1096-3642.2007.00302.x|issn=0024-4082|doi-access=free}}</ref> The mandibles can be retracted inside the body and are responsible for striking and stunning prey; they are capable of snapping some prey in half.<ref name=eol/> Typically, ''E. aphroditois'' ranges from deep purple to black, with an iridescent skin. The largest known specimen on record reached 299 cm (9.81 ft) in length,<ref name="extraordinary"/> making it the longest known member of the polychaete class. Despite these great lengths, the worms are slim, with the body only about 25.5 mm (1.00 in) wide. thumb|In an aquarium, showing length

==Habitat== This species may be found prowling in prey-rich coral reefs, where its coloration allows it to blend in and its slim body enables it to hunt in tight places.<ref name=eol/> It inhabits a wide range of other habitats,<ref>{{Cite journal|last=Fernando|first=Olivia J.|year=2011|title=Eunicid Polychaetes (Annelida) from Great Nicobar Island, India: II. Order: Eunicida|url=http://faunaofindia.nic.in/PDFVolumes/records/111/04/0029-0039.pdf|journal=Rec. Zool. Surv. India |volume=111 |issue=Part-4 |pages=29–39|doi=10.26515/rzsi/v111/i4/2011/158819 |s2cid=251713054 }}</ref> particularly sandy and muddy sediments, as well as around rocks and sponges.<ref name=eol/> It has been recorded at depths of up to {{convert|95|m|0|sp=us}}.<ref name=slb>{{Cite web|url=https://www.sealifebase.ca/summary/Eunice-aphroditois.html|title=Eunice aphroditois, bobbit worm|website=www.sealifebase.ca|access-date=2019-04-16}}</ref>

===Diet and interactions=== ''Eunice aphroditois'' senses passing prey with its antennae, seizes the prey with its mandibles, and drags it into its burrow. This species is considered not only a carnivore, feeding on a plethora of species of fish, but also an herbivore or omnivore, feeding on algae, as well as a decomposer, feeding on dead and decaying matter.<ref>{{Cite journal|last=Eriksson|first=Mats|date=2017|title=Earth's oldest 'Bobbit worm' – gigantism in a Devonian eunicidan polychaete|journal=Scientific Reports|volume=7|article-number=43061|doi=10.1038/srep43061|pmid=28220886|pmc=5318920|bibcode=2017NatSR...743061E}}</ref>

To reduce predation risk, some fish engage in mobbing behavior, during which a group of fish will direct jets of water into the worm's burrow to disorient it.<ref name="haag2016" />

Ancestral species may have exhibited the same hunting behavior 20 million years ago, according to fossil records.<ref>{{Cite journal|last=Pan|first=Yu-Yen|date=2021|title=The 20-million-year old lair of an ambush-predatory worm preserved in northeast Taiwan|journal=Scientific Reports|volume=11|issue=1|article-number=1174|doi=10.1038/s41598-020-79311-0|pmid=33479265|pmc=7820589|bibcode=2021NatSR..11.1174P}}</ref>

==Life cycle== thumb|A bristle worm|alt=Image of a bristle worm

''Eunice aphroditois''{{'}}s sexual reproduction organs have not been fully studied, so there is no clear understanding of how it reproduces, though its reproduction might be similar to that of polychaetes.

The lifespan of ''E. aphroditois'' is believed to be three to five years.<ref>{{Cite journal |last=Holthuis |first=L.B. |date=1987 |title=Résultats des campagnes Musorstom. I et II - Philippines (1976, 1980). Tome 2. In: Mémoires du Muséum National d'Histoire Naturelle. Série A, Zoologie. Tome 133. Décembre 1985. Paris. 525 pp. Price: 350 Fr. To be ordered from: Editions du Muséum National d'Histoire Naturelle, Bibliothèque centrale du Muséum, 38 rue Geoffroy Saint-Hilaire, 75005, Paris |journal=Crustaceana |volume=53 |issue=3 |page=320 |doi=10.1163/156854087x00466 |bibcode=1987Crust..53..320H |issn=0011-216X}}</ref>

===Regeneration and reproduction===

''E. aphroditois'' is capable of limited regeneration, primarily of posterior segments (such as the tail), a common trait among many polychaete worms.<ref>{{cite journal |last1=Bely |first1=A. E. |last2=Nyberg |first2=K. G. |title=Evolution of animal regeneration: Re-emergence of a field |journal=Trends in Ecology & Evolution |date=2010 |volume=25 |issue=3 |pages=161–170 |doi=10.1016/j.tree.2009.08.005 |pmid=19800144 |bibcode=2010TEcoE..25..161B }}</ref> While some annelids can regenerate body parts after injury, there is no scientific evidence that E. aphroditois reproduces asexually by splitting into multiple segments. Reports of such behavior appear to stem from misinterpretations of post-mortem or injury-induced movement, rather than verified regenerative reproduction.<ref name="dubioussource">{{cite web |url=https://www.getsurrey.co.uk/news/local-news/bobbit-worms-split-sections-regenerate-6236955 |title=Bobbit worms 'split into sections to regenerate' |last=Stanton |first=Jenny |date=2013-10-24 |website=SurreyLive |publisher=Reach PLC |language=en |access-date=2023-03-12 |quote=This claim appears in a non-scientific news article and lacks support from peer-reviewed scientific literature.}}</ref>{{Contradictory inline|section=Aquaculture|reason=Contradicted in next section.|date=October 2025}}

''E. aphroditois'' reproduces sexually. During spawning, individuals release sperm and eggs into the water column, where external fertilization occurs. The resulting embryos develop into planktonic trochophore larvae, which drift before settling and metamorphosing into juvenile worms.<ref>{{cite journal |last=Glasby |first=C. J. |title=Polychaete reproductive and developmental biology: A review |journal=Hydrobiologia |volume=535–536 |pages=299–318 |year=2005 |doi=10.1007/s10750-004-5452-9 |doi-broken-date=2 November 2025 }}</ref> This mode of reproduction is consistent with many other members of the order Eunicida.

==Aquaculture== While not commonly kept in aquaculture, individuals of ''E. aphroditois'' are occasionally found in home aquaria, where smaller specimens can evade detection by being transported into the tank in live rocks, where they then grow in size.<ref>{{Cite news |date=2013-10-14 |title=Bobbit worm found at Woking aquatics store |language=en-GB |work=BBC News |url=https://www.bbc.com/news/uk-england-surrey-24523612 |access-date=2022-09-01}}</ref> As ''E. aphroditois'' hunts fish, it will deplete the aquarium's stock by direct predation.<ref>{{Cite web |last=Callum |title=Bobbit Worm |url=https://www.rockncritters.co.uk/news/post/bobbit-worm |access-date=2022-09-01 |website=RockNCritters |language=en}}</ref>

''E. aphroditois'' can be difficult to remove from aquariums due to its ability to split into new individuals when cut in half,<ref name="surrey">{{cite web |url=https://www.getsurrey.co.uk/news/local-news/bobbit-worms-split-sections-regenerate-6236955 |title=Bobbit worms 'split into sections to regenerate' |last=Stanton |first=Jenny |date=2013-10-24 |website=SurreyLive |publisher=Reach PLC |language=en |access-date=2023-03-12}}</ref>{{Contradictory inline|section=Life cycle|reason=Contradicted in previous section.|date=February 2026}} dig holes into rocks, and to curl up and hide in small rocks despite its length.<ref>{{cite web |url=https://whyy.org/segments/liz-bobbit-worm/ |title=The Bobbit Worm Chronicles: One man's epic battle against the sea's creepiest crawly |last=Tung |first=Liz |date=2022-11-25 |website=WHYY |language=en |access-date=2023-03-12}}</ref>

==Fossil record== Fossil burrows from the Miocene of northeastern Taiwan have been likened to those of ''E. aphroditois''. The burrows, classified in the ichnogenus ''Pennichnus'', have been found preserved in fine-grained sandstone. They are L-shaped and can reach up to {{convert|2|m}} in length, with a vertical section covered in feather-like collapse structures comprising around 40% of the burrow length, connected by a short intermediate section to a horizontal section accounting for 50% of the length. The burrows are on average {{convert|2.5|cm}} wide at the entrance, and taper down to {{convert|2|cm}} at the end of the horizontal section.<ref>{{Cite journal |last1=Pan |first1=Yu-Yen |last2=Nara |first2=Masakazu |last3=Löwemark |first3=Ludvig |last4=Miguez-Salas |first4=Olmo |last5=Gunnarson |first5=Björn |last6=Iizuka |first6=Yoshiyuki |last7=Chen |first7=Tzu-Tung |last8=Dashtgard |first8=Shahin E. |date=2021-01-21 |title=The 20-million-year old lair of an ambush-predatory worm preserved in northeast Taiwan |journal=Scientific Reports |language=en |volume=11 |issue=1 |article-number=1174 |doi=10.1038/s41598-020-79311-0 |issn=2045-2322 |pmc=7820589 |pmid=33479265 |bibcode=2021NatSR..11.1174P }}</ref>

==References== {{Commons category}} {{Reflist|refs= <ref name="bbccormier">{{cite web |last1=Cormier |first1=Zoe |title=Snapping death worms can hide undetected for years |url=https://www.bbcearth.com/blog/?article=snapping-death-worms-can-hide-undetected-for-years |website=BBC Earth |access-date=14 January 2020 |language=en-gb}}</ref>

<ref name="eol">{{Cite web|url=https://eol.org/pages/404312|title=Eunice aphroditois (Pallas 1788) - Encyclopedia of Life|website=eol.org}}</ref>

<ref name=giangrande2003>{{Cite journal|last1=Giangrande|first1=A.|last2=Delos|first2=A. L.|last3=Fraschetti|first3=S.|last4=Musco|first4=L.|last5=Licciano|first5=M.|last6=Terlizzi|first6=A.|date=2003-12-01|title=Polychaete assemblages along a rocky shore on the South Adriatic coast (Mediterranean Sea): patterns of spatial distribution|journal=Marine Biology|language=en|volume=143|issue=6|pages=1109–1116|doi=10.1007/s00227-003-1162-0|bibcode=2003MarBi.143.1109G |s2cid=85293536|issn=1432-1793}}</ref>

<ref name="haag2016">{{Cite journal|last1=Haag-Wackernagel|first1=Daniel|last2=Lachat|first2=Jose|date=2016-09-12|title=Novel mobbing strategies of a fish population against a sessile annelid predator|journal=Scientific Reports|language=en|volume=6|article-number=33187|doi=10.1038/srep33187|pmid=27615670|issn=2045-2322|pmc=5018815|bibcode=2016NatSR...633187L}}</ref>

<ref name="worms">{{Cite web|url=http://www.marinespecies.org/aphia.php?p=taxdetails&id=130053|title=WoRMS- World Register of Marine Species|last=Fauchald|first=Kristian}}</ref>

<ref name=worms>{{Cite web|url=http://www.marinespecies.org/aphia.php?p=taxdetails&id=130053|title=WoRMS- World Register of Marine Species|last=Fauchald|first=Kristian}}</ref> }}

Category:Errantia Category:Animals described in 1788 Category:Annelids of the Indian Ocean