Editing Myopsida (section)

{{Short description|Order of squids}}
{{Automatic taxobox
| fossil_range = {{fossil range|Eocene|recent|[[Eocene]] - recent<ref name="Mironenko2021"/>}}
| image = Squid eye.jpg
| image_caption = Eye of myopsid squid showing corneal membrane and lack of secondary eyelid
| taxon = Myopsida
| authority = [[Alcide d'Orbigny|d'Orbigny]], 1841<ref name = WoRMS>{{cite web | url = http://www.marinespecies.org/aphia.php?p=taxdetails&id=11728 | title = Myopsida | accessdate = 22 February 2018 | publisher = Flanders Marine Institute | author = Philippe Bouchet | year = 2018 | website = World Register of Marine Species}}</ref>
| subdivision_ranks = Families
| subdivision = [[Australiteuthidae]]<br>
[[Loliginidae]]
}}

'''Myopsida''' is one of the four [[Order (biology)|orders]] of [[squid]]. It consists of two [[family (biology)|families]]: the [[monotypic]] ''[[Australiteuthis]]'' and the diverse and commercially important [[Loliginidae]] (~50 species). Some [[taxonomist]]s classify this taxon as a  suborder of the order [[Teuthida]], in which case it is known as Myopsina. This reclassification is due to Myopsina and [[Oegopsina]] not being demonstrated to form a [[clade]].<ref name = Timetree>{{cite book | editor1 = S. Blair Hedges | editor2 = Sudhir Kumar | year = 2009 | title = The Timetree of Life | chapter = Cephalopod mollusks Cephalopoda | pages = 2–18 | publisher = OUP Oxford  | author1 = Jan M. Strugnell | author2 = Annie Lindgren | author3 = Louise M. Allcock | author3-link = Louise Allcock }}</ref>

A number of morphological features distinguish members of Myopsida from those of its sister group, [[Oegopsida]]. Some of the most obvious differences are found in the structure of the [[cephalopod eye|eyes]]: those of myopsid squids lack a [[secondary eyelid]] and are instead covered by a transparent [[cephalopod cornea|corneal membrane]], the opening of which is reduced to a microscopic [[eye pore|anterior pore]] in most species. The [[cephalopod limb|arms and tentacles]] are ornamented with simple [[cephalopod sucker|suckers]] (hooks are never present), with additional suckers usually borne on the [[buccal lappet]]s. The carpal ("wrist") portion of the [[tentacular club]] lacks a [[carpal-locking apparatus|locking apparatus]], and a [[tentacle pocket]] is present on the head. The [[siphon (mollusc)|funnel]] has no lateral [[Adductor muscle (Bivalvia)|adductor muscles]]. An internalised shell is present in the form of a well-developed [[Gladius (cephalopod)|gladius]], which is located dorsally within the [[mantle (mollusc)|mantle]] and extends for almost its entire length. In contrast to oegopsids, females possess [[accessory nidamental gland]]s in addition to the main [[nidamental gland]]s. They however lack a right [[oviduct]].<ref name=squids>Jereb, P. & C.F.E. Roper (2010). Squids. In: P. Jereb & C.F.E. Roper (eds.) ''[http://www.fao.org/docrep/014/i1920e/i1920e00.htm Cephalopods of the world. An annotated and illustrated catalogue of species known to date. Volume 2. Myopsid and Oegopsid Squids]''. FAO Species Catalogue for Fishery Purposes No. 4, Vol. 2. FAO, Rome. pp.&nbsp;34–35.</ref><ref name=Myopsida>Vecchione, M. & R.E. Young (2008). [http://www.tolweb.org/Myopsida/52670 Myopsida Naef, 1916]. [[Tree of Life Web Project]].</ref>

Myopsids are found in [[neritic zone|coastal waters]] worldwide. They are [[demersal zone|demersal]], generally feeding on or near the bottom.<ref name=squids /><ref name=Myopsida />  In turn, they are considered prey items by virtually all marine predators, including birds.

Adult sizes range from the dwarf ''[[Australiteuthis]]'' and ''[[Pickfordiateuthis]]'', whose males mature at less than {{convert|2|cm|in|abbr=on}} in mantle length (ML),<ref name=squids /><ref name=Myopsida /> to the largest species ''[[Loligo forbesii]]'', which has been measured to {{convert|93.7|cm|ft|abbr=on}} ML.<ref>[https://www.cambridge.org/core/journals/marine-biodiversity-records/article/abs/azorean-loligo-forbesi-cephalopoda-loliginidae-in-captivity-transport-handling-maintenance-tagging-and-survival/B348C459B4EDFB2A530EA33DA4C88CB4 The Azorean Loligo forbesi (Cephalopoda: Loliginidae) in captivity: transport, handling, maintenance, tagging and survival]</ref><ref>[https://assets.researchsquare.com/files/rs-1926159/v1/a1b1c776-782d-4066-9c21-4b5cbb6aa7a6.pdf?c=1694444921 Body size and fin length as determinants in the geographic distribution of Loliginid squids]</ref> The earliest fossils of this group are ''[[Loligo]]'' [[Statocyst|statoliths]] from the early [[Eocene]] of [[North America]]. In addition, a pyritized ''Loligo'' fossil is known from the [[Oligocene]] of [[Russia]], marking the earliest true squid known from a complete body fossil.<ref name="Mironenko2021">{{Cite journal |last=Mironenko |first=Aleksandr A. |last2=Boiko |first2=Maxim S. |last3=Bannikov |first3=Alexandre F. |last4=Arkhipkin |first4=Alexander I. |last5=Bizikov |first5=Viacheslav A. |last6=Košťák |first6=Martin |date=10 August 2021 |title=First discovery of the soft‐body imprint of an Oligocene fossil squid indicates its piscivorous diet |url=https://www.idunn.no/doi/10.1111/let.12440 |journal=Lethaia |language=en |volume=54 |issue=5 |pages=793–805 |doi=10.1111/let.12440 |issn=0024-1164|url-access=subscription }}</ref>