# Squilla

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{{Short description|Genus of crustaceans}}
{{Automatic taxobox
| image= Squilla mantis.jpg
| image_caption = ''[Squilla mantis](/source/Squilla_mantis)''
| taxon = Squilla
| authority = [Fabricius](/source/Johan_Christian_Fabricius), 1787
| type_species = ''[Cancer mantis](/source/Squilla_mantis)''
| type_species_authority = [Linnaeus](/source/Carl_Linnaeus), [1758](/source/10th_edition_of_Systema_Naturae)
}}

'''''Squilla''''' is a [genus](/source/genus) of [mantis shrimp](/source/mantis_shrimp) found in marine habitats in [tropical](/source/Tropics) and [sub-tropical](/source/sub-tropical) climates all over the world, such as the [Indian Ocean](/source/Indian_Ocean) and [Mediterranean sea](/source/Mediterranean_Sea).<ref>{{Cite web |title=Squilla mantis, Spottail mantis shrimp : fisheries, gamefish |url=https://www.sealifebase.se/summary/Squilla-mantis.html |access-date=2025-04-21 |website=www.sealifebase.se}}</ref> They are often [caught unintentionally](/source/Bycatch) by fisheries in their climate, and they are not used for human food or [fish meal](/source/fish_meal),{{Citation needed|date=September 2025|reason=Squilla mantis has been fished commercially for centuries}} though valuable compounds such as [chitin](/source/chitin) and [chitosan](/source/chitosan) can be extracted from their shells.<ref name=":0" /> The genus first appeared in the [fossil record](/source/fossil_record) 145 million years ago.<ref name=":4" />

==Taxonomy==
This genus includes the following species:<ref>{{cite WoRMS |year=2011 |title=''Squilla'' Fabricius, 1787 |id=136113 |accessdate=January 16, 2012}}</ref>{{Update inline|date=September 2025|reason=taxonomic list}}
{{div col|colwidth=21em}}
*''[Squilla aculeata](/source/Squilla_aculeata)'' <small>[Bigelow](/source/Robert_Payne_Bigelow), 1893</small>
*''[Squilla biformis](/source/Squilla_biformis)'' <small>Bigelow, 1891</small>
*''[Squilla bigelowi](/source/Squilla_bigelowi)'' <small>Schmitt, 1940</small>
*''[Squilla brasiliensis](/source/Squilla_brasiliensis)'' <small>Calman, 1917</small>
*''[Squilla cadenati](/source/Squilla_cadenati)'' <small>Manning, 1970</small>
*''[Squilla caribaea](/source/Squilla_caribaea)'' <small>Manning, 1969</small>
*''[Squilla chydaea](/source/Squilla_chydaea)'' <small>Manning, 1962</small>
*''[Squilla deceptrix](/source/Squilla_deceptrix)'' <small>Manning, 1969</small>
*''[Squilla discors](/source/Squilla_discors)'' <small>Manning, 1962</small>
*''[Squilla edentata](/source/Squilla_edentata)'' <small>(Lunz, 1937)</small>
*''[Squilla empusa](/source/Squilla_empusa)'' <small>Say, 1818</small>
*''[Squilla grenadensis](/source/Squilla_grenadensis)'' <small>Manning, 1969</small>
*''[Squilla hancocki](/source/Squilla_hancocki)'' <small>Schmitt, 1940</small>
*''[Squilla intermedia](/source/Squilla_intermedia)'' <small>Bigelow, 1893</small>
*''[Squilla latreillei](/source/Squilla_latreillei)''
*''[Squilla lijdingi](/source/Squilla_lijdingi)'' <small>Holthuis, 1959</small>
*''[Squilla mantis](/source/Squilla_mantis)'' <small>([Linnaeus](/source/Carl_Linnaeus), [1758](/source/10th_edition_of_Systema_Naturae))</small>
*''[Squilla mantoidea](/source/Squilla_mantoidea)'' <small>Bigelow, 1893</small>
*''[Squilla obtusa](/source/Squilla_obtusa)'' <small>Holthuis, 1959</small>
*''[Squilla panamensis](/source/Squilla_panamensis)'' <small>Bigelow, 1891</small>
*''[Squilla parva](/source/Squilla_parva)'' <small>Bigelow, 1891</small>
*''[Squilla rugosa](/source/Squilla_rugosa)'' <small>Bigelow, 1893</small>
*''[Squilla surinamica](/source/Squilla_surinamica)'' <small>Holthuis, 1959</small>
*''[Squilla tiburonensis](/source/Squilla_tiburonensis)'' <small>Schmitt, 1940</small>
{{div col end}}
==Description==
Though the many species of the ''Squilla'' genus vary greatly in location, they are all defined by a few common shared traits, or [synapomorphies](/source/synapomorphies). One of those notable ones is the number of teeth on their claw, which tends to be of a middling size. Because ''Squilla'' lack a hardened "smashing" appendage like some of their fellow [stomatopod](/source/stomatopod) genera, they cannot break open hard shells, and thus largely subsist on soft-bodied prey for food.<ref name=":5">{{Cite journal |last=Burrows |first=M. |date=1969-12-01 |title=The mechanics and neural control of the prey capture strike in the mantid shrimps Squilla and Hemisquilla |url=https://link.springer.com/article/10.1007/BF00299261 |journal=Zeitschrift für vergleichende Physiologie |language=en |volume=62 |issue=4 |pages=361–381 |doi=10.1007/BF00299261 |issn=1432-1351|url-access=subscription }}</ref> The claw of the ''Squilla'' genus is known to have six teeth. Another defining trait is the lack of a raised ridge in the exoskeleton of ''Squilla'' — or rather, the extension of the ridge over the entire exoskeleton, as such creating the appearance of the lack of a ridge. Often referred to as a "carina", this ridge can be used to differentiate ''Squilla'' from other similar stomatopods.<ref name=":2">{{Cite journal |last1=Tiwari |first1=Krishna Kant |last2=Biswas |first2=Sadabrata |date=1952-12-01 |title=On Two New Species of the Genus ''Squilla'' Fabr., with Notes on Other Stomatopods in the Collections of the Zoological Survey of India |url=https://recordsofzsi.com/index.php/zsoi/article/view/162116 |journal=Records of the Zoological Survey of India |volume=49 |issue=3–4 |page=349 |doi=10.26515/rzsi/v49/i3-4/1952/162116 |language=en |issn=2581-8686 |archive-url=https://web.archive.org/web/20250206133757/https://recordsofzsi.com/index.php/zsoi/article/view/162116 |archive-date=2025-02-06|doi-access=free }}</ref>
thumb|A 1913 account of a species within the Squilla genus, found in the Indo-Pacific region of Calcutta.
Aside from these major features used to differentiate ''Squilla,'' other features include a tail plate with four to six spines, unlike the fused tail plates found in other stomatopods, and shorter antennular peduncles, which are the structures at the base of the shrimp's antennae that attach them to their head.<ref name=":2" />

''Squilla'' are small, [bilaterally symmetrical](/source/bilaterally_symmetrical) marine organisms,<ref name=":4">{{Cite web |title=Search: squilla - Encyclopedia of Life |url=https://eol.org/search/?q=Squilla&search=Go |access-date=2025-04-21 |website=eol.org}}</ref> with a size range of {{convert|40|-|70|mm|abbr=out}}. The males and females tend to be the same size.<ref name=":1">{{Cite journal |last1=Chhapgar |first1=B. F. |last2=Sane |first2=S. R. |date=1967-01-01 |title=Two New Species of Squilla (Stomatopoda) From Bombay |url=https://brill.com/view/journals/cr/12/1/article-p1_1.xml?language=en&srsltid=AfmBOooPFFyBysGPOccSi5CjMuy9gTVrOGvobhE7AGYgAQz2fkPSxMDs |journal=Crustaceana |language=en |volume=12 |issue=1 |pages=1–8 |doi=10.1163/156854067X00657 |bibcode=1967Crust..12....1S |issn=1568-5403|url-access=subscription }}</ref> All the different species possess a form that is typical of most other stomatopods, consisting of extended [eyestalk](/source/eyestalk)s, a [rostrum](/source/Rostrum_(anatomy)), [carapace](/source/carapace), and a raptorial claw used for hunting.<ref name=":1" />

Additionally, ''Squilla'' have developed a [nauplius eye](/source/Naupliar_eye), which is an eye that is composed of three to four pigment [ocelli](/source/ocelli). Likely, this eye only allows the organism to determine the location of a light source. This means species within the ''Squilla'' genus have poorer eyesight than their more famous counterparts of the ''[Odontodactylus](/source/Odontodactylus)'' genus,{{Verify source|date=September 2025}} which can see more colors than even humans.{{Tone inline|date=September 2025|reason=This feels uncomfortably similar to the shrimp colors meme}}<ref>{{Cite journal |last1=Donohue |first1=Mary W. |last2=Cohen |first2=Jonathan H. |last3=Cronin |first3=Thomas W. |date=2018-06-26 |title=Cerebral photoreception in mantis shrimp |journal=Scientific Reports |volume=8 |issue=1 |pages=9689 |doi=10.1038/s41598-018-28004-w |issn=2045-2322 |pmc=6018774 |pmid=29946145|bibcode=2018NatSR...8.9689D }}</ref>

== Behavior ==
''Squilla'' are predatory [benthic](/source/Benthos) [burrow](/source/burrow)ers, akin to many other . They dig holes in the sand, hide, and await soft bodied prey that they are able to snatch up with their relatively weak claw.<ref name=":0">{{Cite journal |last=Wortham |first=Jennifer |date=2009-01-01 |title=Abundance and Distribution of Two Species of Squilla (Crustacea: Stomatopoda: Squillidae) in the Northern Gulf of Mexico |url=https://aquila.usm.edu/gcr/vol21/iss1/1/ |journal=Gulf and Caribbean Research |volume=21 |issue=1 |pages=1–12 |doi=10.18785/gcr.2101.01 |bibcode=2009GCRes..21....1W |issn=1528-0470}}</ref> This means that, unlike other genera of Stomatopods, ''Squilla'' cannot typically consume prey with hard shells. They tend to prey on other benthic organisms such as [worms](/source/Marine_worm), [krill](/source/krill),{{Citation needed|date=September 2025|reason=what krill coexists with Squilla?}} small fish, and even other species of ''Squilla'' when they are able. Their burrowing habit makes them a bio-diffuser, as they engage in [ecosystem engineering](/source/ecosystem_engineering) that scatters organic and inorganic particles about the ocean floor. <ref name=":5" /> Despite their small size, ''Squilla'' has found great success with their strategy, as they have been around for over one hundred million years and have diversified into over a dozen different species.{{Tone inline|date=September 2025}}

=== Life cycle ===
''Squilla'' go through five maturity stages, that being the immature, early maturation, maturation, ripe, and spent stages, with their life cycle ending shortly after they reproduce ([semelparity](/source/Semelparity_and_iteroparity)).<ref name=":3" /> Their life cycles are short, being only eighteen months at the longest, and their [reproductive season](/source/reproductive_season) begins in spring, with most females going from maturation to ripe in winter and ending their life cycle spent in summer. In the studies that determined this, the stage of a female's life cycle was determined by how much space her [ovaries](/source/Ovary) consumed in regards to her entire body mass. In spring and summer, females tend to hide in galleries and tend to their eggs, leading to fisheries to catch more males. But in autumn, the females will leave the galleries and become more vulnerable to being caught by humans.<ref name=":3">{{Cite journal |last1=Colella |first1=Sabrina |last2=Mascoli |first2=Alessia |last3=Donato |first3=Fortunata |last4=Panfili |first4=Monica |last5=Santojanni |first5=Alberto |last6=Gioacchini |first6=Giorgia |date=2024-08-28 |title=Reproductive Dynamics of Spot Tail Mantis Shrimp (Squilla mantis): Insights from the Central Mediterranean Sea |journal=Animals |volume=14 |issue=17 |pages=2503 |doi=10.3390/ani14172503 |pmid=39272288 |doi-access=free |issn=2076-2615|hdl=10261/368481 |hdl-access=free |pmc=11394382 }}</ref>

== Relation to humans ==
thumb|Squilla exoskeletons being harvested for chitosan production.
Though ''Squilla'' offers little nutritional value due to its very small size, the compounds [chitin](/source/chitin) and [chitosan](/source/chitosan) are able to be extracted from ''Squilla'' exoskeletons, as is the case with many crustacean species. Chitosan, in particular, has been found to reduce [blood plasma](/source/blood_plasma) levels of [HDL](/source/High-density_lipoprotein) in humans, as well as protect against the growth of some microorganisms, most notably the yeast ''[Candida](/source/Candida_(fungus))''.<ref>{{Cite journal |doi=10.12944/CWE.12.3.18 |s2cid=55062863 |title=Comparison of the Quality of Chitin and Chitosan from Shrimp, Crab and Squilla Waste |date=2017 |last1=Parthiban |first1=F. |last2=Balasundari |first2=S. |last3=Gopalakannan |first3=A. |last4=Rathnakumar |first4=K. |last5=Felix |first5=S. |journal=Current World Environment |volume=12 |issue=3 |pages=670–677 |doi-access=free }}</ref> New research has also demonstrated that chitosan produced from ''Squilla'' shells may also be beneficial in fighting other fungus infections and [cancer](/source/cancer)ous growths.<ref>{{Cite journal |last1=Kalaivani |first1=R. |last2=Maruthupandy |first2=M. |last3=Muneeswaran |first3=T. |last4=Singh |first4=Manoj |last5=Sureshkumar |first5=S. |last6=Anand |first6=M. |last7=Ramakritinan |first7=C. M. |last8=Quero |first8=F. |last9=Kumaraguru |first9=A. K. |date=2020-03-01 |title=Chitosan mediated gold nanoparticles against pathogenic bacteria, fungal strains and MCF-7 cancer cells |url=https://www.sciencedirect.com/science/article/abs/pii/S0141813019341558 |journal=International Journal of Biological Macromolecules |volume=146 |pages=560–568 |doi=10.1016/j.ijbiomac.2020.01.037 |pmid=31917985 |issn=0141-8130|url-access=subscription }}</ref>

These chemicals are extracted by first collecting large amounts of ''Squilla'', which is often done unintentionally by fisheries who catch ''Squilla'' in their net while fishing for other larger species. These catches are then shelled, and the shells are put through multiple chemical treatments, including [demineralization](/source/Demineralization_(physiology)), decolorization, [deproteinization](/source/Deproteination), and [deacetylation](/source/deacetylation), before they can become finished commercial grade chitosan.<ref>{{Cite journal |last=Abouzied |first=Abdel-Rahman S. |display-authors=etal |date=2024-01-01 |title=Characterization of Chitosan Extracted from Upper and Lower Squilla species Shells |journal=Egyptian Journal of Aquatic Biology and Fisheries |volume=28 |issue=1 |pages=261–279 |doi=10.21608/ejabf.2024.337882 |issn=2536-9814|doi-access=free }}</ref>

==References==
{{Reflist}}

{{Taxonbar|from=Q3859898}}

Category:Stomatopoda

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Adapted from the Wikipedia article [Squilla](https://en.wikipedia.org/wiki/Squilla) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Squilla?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.