Editing Bobtail squid

{{short description|Order cephalopod molluscs closely related to cuttlefish}}
{{Automatic taxobox
| taxon = Sepiolida
| name = Bobtail squid
| image = Sepiola atlantica.jpg
| image_caption = ''[[Sepiola atlantica]]''
| authority = [[P. v. Fioroni|Fioroni]], 1981
| subdivision_ranks = Families
| subdivision = 
[[Idiosepiidae]]<br/>
[[Sepiolidae]]
}}

'''Bobtail squid''' (order Sepiolida)<ref name="Sanchez_al.2019">{{cite journal |author1=Gustavo Sanchez |author2=Jeffrey Jolly |author3=Amanda Reid |author4=Chikatoshi Sugimoto |author5=Chika Azama |author6=Ferdinand Marlétaz |author7=Oleg Simakov |author8=Daniel S. Rokhsar |title=New bobtail squid (Sepiolidae: Sepiolinae) from the Ryukyu islands revealed by molecular and morphological analysis |journal=[[Communications Biology]] |volume=2 |issue=465 |pages=465 |doi=10.1038/s42003-019-0661-6 |pmid=31840110 |pmc=6906322 |date=2019-12-11 }}</ref> are a group of [[cephalopods]] closely related to [[cuttlefish]]. Bobtail squid tend to have a rounder [[mantle (mollusc)|mantle]] than cuttlefish and have no [[cuttlebone]]. They have eight suckered arms and two tentacles and are generally quite small (typical male mantle length being between {{convert|1|and|8|cm|in|abbr=on}}).<ref name=McFall-Ngai />

Sepiolids live in shallow [[coastal]] waters of the [[Pacific Ocean]] and some parts of the [[Indian Ocean]] and [[Atlantic Ocean]] as well as in shallow waters on the west coast of the [[Cape Peninsula]] off South Africa. Like cuttlefish, they can swim by either using the [[Cephalopod fin|fins]] on their mantle or by jet propulsion. They are also known as "dumpling squid" (owing to their rounded mantle) or "stubby squid".

== Light organ ==
[[File:Bobtail squid light organ silhouette.svg|thumb|alt=Diagram showing how the light organ in a bobtail squid emits light downwards to obscure its silhouette|Light from the light organ of a bobtail squid obscures its silhouette]]

Bobtail squid have a [[symbiotic]] relationship with [[bioluminescent]] [[bacteria]] (''[[Aliivibrio fischeri]]''), which inhabit a special light organ in the squid's mantle. The luminescent properties of the bacteria regulate gene expression in the light organ.<ref>{{Cite journal|last=Peyer|first=Suzanne M.|last2=Pankey|first2=M. Sabrina|last3=Oakley|first3=Todd H.|last4=McFall-Ngai|first4=Margaret J.|date=February 2014|title=Eye-specification genes in the bacterial light organ of the bobtail squid Euprymna scolopes, and their expression in response to symbiont cues|journal=Mechanisms of Development|volume=131|pages=111–126|doi=10.1016/j.mod.2013.09.004|issn=0925-4773|pmc=4000693|pmid=24157521}}</ref> The bacteria are fed a sugar and amino acid solution by the squid and in return hide the squid's [[silhouette]] when viewed from below by matching the amount of light hitting the top of the mantle. This method of [[counter-illumination]] is an example of animal [[camouflage]].

The organ contains filters which may alter the [[wavelength]] of luminescence closer to that of downwelling [[moonlight]] and [[star#Radiation|starlight]]; a [[lens (anatomy)|lens]] with [[biochemical]] similarities to the squid's eye to diffuse the bacterial luminescence; and a [[mirror|reflector]] which directs the light [[ventral]]ly.<ref name=McFall-Ngai />

== Reproduction ==
Sepiolida are [[iteroparous]] and a female might lay several clutches, each of 1–400 eggs (dependent on [[species]]), over her estimated one-year-long lifetime.<ref name=McFall-Ngai /> The eggs are covered with sand and left without parental care.<ref name=McFall-Ngai/> Symbiosis with ''A. fischeri'' from the surrounding seawater is initiated immediately upon hatching, and the bacteria's [[Colonisation (biology)|colonisation]] of the [[Juvenile (organism)|juvenile]] light-organ induces [[morphology (biology)|morphological]] changes in the squid that lead to [[Sexual maturity|maturity]].<ref name=McFall-Ngai />

== Classification ==
[[File:Bobtail squid.jpg|thumb|250px|''[[Euprymna berryi]]'' from [[East Timor]]]]

About seventy species are known. Sepiolid taxonomy within the [[Coleoidea|coleoid]] cephalopods is currently controversial, thus their position is subject to future change.<ref name=McFall-Ngai>{{cite journal |author=McFall-Ngai, M.J. |title=Consequences of evolving with bacterial symbionts: Insights from the Squid-Vibrio Associations |journal=Annual Review of Ecology and Systematics
|volume=30 |pages=235–256  |year=1999|doi=10.1146/annurev.ecolsys.30.1.235}}</ref>
*Class [[Cephalopod]]a
**Subclass [[Nautiloidea]]: nautilus
**Subclass [[Coleoidea]]: [[squid]], [[octopus]], [[cuttlefish]]
***Superorder [[Decapodiformes]]
****Order [[Spirulida]]: ram's horn squid
****Order [[Sepiida]]: cuttlefish
****'''Order Sepiolida''': bobtail squid
*****Family [[Idiosepiidae]]
*****Family [[Sepiolidae]]
****Order [[Teuthida]]: squid
***Superorder †[[Palaeoteuthomorpha]]
****Order †[[Boletzkyida]]
***Superorder [[Octopodiformes]]

== References ==
{{Reflist}}

== External links ==
*[https://web.archive.org/web/20051218205946/http://www.cephbase.utmb.edu/spdb/bobtail.cfm CephBase: Sepiolida]
*[http://web.uconn.edu/mcbstaff/graf/Fischeri.html Squid-bacteria symbiosis]

{{Taxonbar|from=Q244417}}

{{DEFAULTSORT:Bobtail Squid}}
[[Category:Bobtail squid| ]]
[[Category:Squid]]
[[Category:Cenozoic cephalopods]]
[[Category:Miocene molluscs]]
[[Category:Pliocene molluscs]]
[[Category:Cephalopods described in 1981]]