Editing Cetomimoidea

{{Short description|Order of ray-finned fishes}}
{{Automatic taxobox
| name = Whalefishes
| fossil_range = {{fossil range|Early Eocene|recent}}
| image = flabby whalefish.jpg
| image_caption = ''[[Barbourisiidae|Barbourisia rufa]]''
| classification_status = disputed
| taxon = Cetomimoidea
| authority = Nelson, 1994
| subdivision_ranks = Families
| subdivision = [[Barbourisiidae]]<br/>
[[Cetomimidae]]<br/>
[[Rondeletiidae]]
}}

The '''Cetomimoidea''' or '''whalefishes''' are a [[Superfamily (biology)|superfamily]] of small, deep-sea [[ray-finned fish]]. Formerly treated as either their own order ('''Cetomimiformes''') due to their unusual anatomy,<ref>E.g. Nelson (2006)</ref> more recent studies incorporating genetic data confirm them to be deeply nested within the [[Beryciformes]] as a clade within [[Stephanoberycoidei]] (which was formerly also treated as its own order).<ref name=":1">{{Cite web |last=Fricke |first=R. |last2=Eschmeyer |first2=W. N. |last3=Van der Laan |first3=R. |date=2025 |title=ESCHMEYER'S CATALOG OF FISHES: CLASSIFICATION |url=https://www.calacademy.org/eschmeyers-catalog-of-fishes-classification |access-date=2025-02-10 |website=California Academy of Sciences |language=en}}</ref> They are thus better treated as their own superfamily, Cetomimoidea.<ref>{{Cite journal |last=Kobyliansky |first=S. G. |last2=Gordeeva |first2=N. V. |last3=Kotlyar |first3=A. N. |date=2020-01-01 |title=New Findings of the Rare Species Rondeletia bicolor (Stephanoberycoidei) Over the Mid-Atlantic Ridge and Some Peculiarities of the Rondeletiidae Family’s Phylologeny |url=https://link.springer.com/article/10.1134/S0032945220010075 |journal=Journal of Ichthyology |language=en |volume=60 |issue=1 |pages=13–21 |doi=10.1134/S0032945220010075 |issn=1555-6425|url-access=subscription }}</ref><ref>{{Cite journal |last=Mincarone |first=M. M. |last2=Di Dario |first2=F. |last3=Costa |first3=P. a. S. |date=2014 |title=Deep-sea bigscales, pricklefishes, gibberfishes and whalefishes (Teleostei: Stephanoberycoidei) off Brazil: new records, range extensions for the south-western Atlantic Ocean and remarks on the taxonomy of Poromitra |url=https://onlinelibrary.wiley.com/doi/10.1111/jfb.12515 |journal=Journal of Fish Biology |language=en |volume=85 |issue=5 |pages=1546–1570 |doi=10.1111/jfb.12515 |issn=1095-8649|url-access=subscription }}</ref>

Within this group are five families and approximately 18 genera and 32 species (but see below). Thought to have a circumglobal distribution throughout the tropical and temperate [[latitude]]s, whalefishes have been recorded at depths in excess of 3,500 metres.

== Taxonomy ==
Some recent phylogenetic studies suggest that the whalefishes are paraphyletic with respect to other members of the suborder, with ''[[Barbourisia]]'' belonging to the [[Stephanoberycidae]] while [[Rondeletiidae]] includes ''[[Hispidoberyx]]''. Although previously thought to have ancient origins due to their unique morphological characteristics, phylogenetic studies suggest a [[Paleogene]] origin for the group.<ref>{{Cite journal |last=Brownstein |first=Chase D |last2=Dornburg |first2=Alex |last3=Near |first3=Thomas J |date=2025-03-04 |title=Cenozoic evolutionary history obscures the Mesozoic origins of acanthopterygian fishes |url=https://academic.oup.com/evolut/advance-article/doi/10.1093/evolut/qpaf040/8051721 |journal=Evolution |language=en |doi=10.1093/evolut/qpaf040 |issn=0014-3820}}</ref>

Potentially the earliest fossil record of the group is of a ''[[Redmouth whalefish|Rondeletia]]''-like whalefish from the earliest Eocene-aged [[Fur Formation]] of Denmark.<ref>{{Cite journal |last=Bonde |first=Niels |date=2008 |title=Osteoglossomorphs of the marine Lower Eocene of Denmark – with remarks on other Eocene taxa and their importance for palaeobiogeography |url=https://www.lyellcollection.org/doi/10.1144/SP295.14 |journal=Geological Society, London, Special Publications |language=en |volume=295 |issue=1 |pages=253–310 |doi=10.1144/SP295.14 |issn=0305-8719|url-access=subscription }}</ref>

==Description==
Named after their whale-shaped body (from the [[Greek language|Greek]] ''ketos'' meaning "whale" or "sea monster", ''mimos'' meaning "imitative" and the [[Latin]] ''forma'' meaning "form"), the Cetomimiformes have extremely large mouths and highly distensible stomachs. Their eyes are very small or vestigial; the [[lateral line]] (composed of huge, hollow tubes) is consequently very well developed to compensate for life in the pitch black depths.

The dorsal and [[anal fins]] are set far back; all fins lack spines. The [[swim bladder]] is also absent, except in the [[larva]]e and [[Juvenile (organism)|juveniles]] which occur in the surface waters.<ref name = paxtonetal2001>Paxton ''et al.'' (2001)</ref> Whalefish coloration is typically red to orange, sometimes with a black body. Some species possess light-producing organs called [[photophore]]s; these are widespread among deep-sea fishes.

The largest known species reach a length of just 40 centimetres; most species are half this size. [[Sexual dimorphism]] is (apparently) exceptionally strong: males may only grow to 3.5 centimetres while females may be ten times as large. This is not uncommon among deep-sea fishes, with the males serving little use other than as suppliers of sperm: an even more extreme case are the [[parasitic]] males in deep-sea [[anglerfish]].

== Families ==
*[[Cetomimidae]] — flabby whalefishes
*[[Rondeletiidae]] — redmouth whalefishes
*[[Barbourisiidae]] — velvet whalefish ([[monotypic]])

The gibberfishes ([[Gibberichthyidae]]) on the other hand, usually placed in the [[Stephanoberyciformes]] ''sensu stricto'', appear to be close relatives of the [[Rondeletiidae]] and [[Barbourisiidae]], as has been occasionally proposed.<ref name = paxtonetal2001>Paxton ''et al.'' (2001)</ref>

==Footnotes==
{{Reflist}}

==References==
* {{aut|Nelson, J.S.}} (2006): ''[[Fishes of the World]]'' (4th ed.). <small>{{ISBN|0-471-25031-7}}</small>
* {{aut|Paxton, John R.; Johnson, G. David & Trnski, Thomas}} (2001): Larvae and juveniles of the deepsea "whalefishes" ''Barbourisia'' and ''Rondeletia'' (Stephanoberyciformes: Barbourisiidae, Rondeletiidae), with comments on family relationships. ''Records of the Australian Museum'' '''53'''(3): 407–425. [https://web.archive.org/web/20030926004428/http://www.amonline.net.au/pdf/publications/1352_complete.pdf PDF fulltext]

==External links==
* [http://ocean.si.edu/ocean-news/museum-collections-solve-whalefish-mystery/meet-suspects Whalefish - Smithsonian Ocean Portal]
* {{FishBase order | order = Cetomimiformes | month = January | year = 2006}}
* [http://www.aquaticcommunity.com/news/whalefish.com Aquatic community website] {{Webarchive|url=https://web.archive.org/web/20151208101211/http://www.aquaticcommunity.com/news/whalefish.com |date=2015-12-08 }}

{{Actinopterygii}}
{{Taxonbar|from=Q859840}}

[[Category:Beryciformes]]