{{Short description|Species of fish}} {{Speciesbox | name = Butterfly kingfish | image = Gamel_u0.gif | status = LC | status_system = IUCN3.1 | status_ref = <ref name=IUCN>{{cite iucn |author=Collette, B.B. |author2=Di Natale, A. |author3=Pollard, D.A. |author4=Nakatsuka, S. |author5=Suzuki, J. |year=2023 |title=''Gasterochisma melampus'' |volume=2023 |article-number=e.T170340A46940110 |doi=10.2305/IUCN.UK.2023-1.RLTS.T170340A46940110.en |access-date=27 July 2024}}</ref> | display_parents = 2 | taxon = Gasterochisma melampus | grandparent_authority = Lahille, 1903 | parent_authority = Richardson, 1845 | authority = Richardson, 1845 | synonyms = * ''Chenogaster holmbergi''<br /><small>(Lahille, 1903)</small> * ''Lepidothynnus huttoni''<br /><small>(Günther, 1889)</small> }}
The '''butterfly kingfish''' ('''''Gasterochisma melampus''''') is an ocean-dwelling ray-finned bony fish in the mackerel family, Scombridae – a family which it shares with the tunas, mackerels, Spanish mackerels, and bonitos. It, however, represents a lineage distinct from all other scombrids and has therefore been placed in its own genus '''''Gasterochisma''''' and subfamily '''Gasterochismatinae'''.<ref name=WoRMS>{{cite WoRMS |title=Gasterochismatinae Poey, 1869 |year=2024 |id=267119 |db=FishBase |access-date=27 July 2024}}</ref><ref name=ITIS>{{ITIS |id=638249 |taxon=Gasterochismatinae Lahille, 1903 |access-date=27 July 2024}}</ref><ref name=Graham2004/><ref name=Orrell2006/>
Although taxonomists and the Food and Agriculture Organization of the United Nations have accepted the name "butterfly kingfish", this fish has had many common names, including '''big-scaled mackerel''', '''bigscale mackerel''', '''butterfly mackerel''', '''butterfly tuna''', '''scaled tunny''', '''scaly tuna''', and others. In 1993, the U.S. Food and Drug Administration gave approval for this fish to be marketed simply as "mackerel".<ref>{{cite book |last1=Randolph |first1=S. |last2=Snyder |first2=M. |title=The seafood list: FDA's guide to acceptable market names for seafood sold in interstate commerce. |publisher=U.S. Government Printing Office |location=Washington, D.C.}}</ref>
==Description== The juveniles of the butterfly kingfish are characterized by enormous pelvic fins that are longer than the length of its head, and that become more proportional as the fish grows. At any size, the pelvic fin tucks into a deep ventral groove, in much the same way as the first dorsal spines do in all scombrids. This species has very large cycloid scales, below which is a thick layer of fat. The swim bladder has two anterior projections that extend into the back of the skull, near the inner ear.<ref name=Block2001/> This fish lacks the median keel on the caudal peduncle – it only has the characteristic pair of small keels on each side of the base of the caudal fin, as do other scombrids. It has 21 precaudal vertebrae, plus 23 caudal vertebrae.<ref name=Orrell2006/>
thumb|200px|left|Drawing of a butterfly kingfish This fish can be found around the world in southern temperate waters of {{convert|8|–|15|°C|°F}}, but most commonly under {{convert|10|°C|°F}}, and at depths to {{convert|200|m|ft|abbr=on}} in the open ocean. It grows to a length of {{convert|1.64|m|ft|abbr=on}} with a weight of {{cvt|50|kg}}, possible up to {{cvt|70|kg}}.<ref name=FishBase/><ref name=":0">{{Cite web |date=2014-09-26 |title=Mysterious Fish Species from the Deep {{!}} Sport Fishing Mag |url=https://www.sportfishingmag.com/gallery/species/2014/09/bizarre-butterfly-kingfish-and-other-mysterious-fishes-deep/ |access-date=2025-03-12 |language=en-US}}</ref>
Most bony fishes are ectothermic, or cold-blooded, but this species, much like the related tunas, is endothermic and is able to raise its body temperature to achieve a degree of thermoregulation.<ref name=Block1993>{{cite journal |last1=Block |first1=B.A. |last2=Finnerty |first2=J.R. |year=1993 |url=https://www.researchgate.net/publication/226138605 |title=Endothermy in fishes: a phylogenetic analysis of constraints, predispositions, and selection pressures |journal=Environmental Biology of Fishes |volume=40 |issue=3 |pages=283–302 |doi=10.1007/BF00002518 |s2cid=28644501 }}</ref> It has a brain heater organ derived from the lateral rectus eye muscle, which is distinct from that of the billfishes, whose heater is derived from their superior rectus muscles.<ref name=Orrell2006/>
==Etymology== ''Gasterochisma'' derives from the {{langx|grc|γαστήρ|(gaster)|stomach}}, and {{lang|grc|χίασμα}} (''{{Transliteration|grc|chiasma}}'') "crossing; X-shaped; sign of the 'X'".<ref name=FishBase>{{FishBase | genus = Gasterochisma | species = melampus | month = February | year = 2024}}</ref>
==Taxonomy== The evolutionary lineage of the butterfly kingfish is more primitive and quite different from that of the rest of the scombrids. Additionally, the morphology of this species is substantially different from that of the others – some suggest that it might belong in a different family altogether.<ref name=Block2001>{{Cite book |title=Tuna: physiology, ecology, and evolution; Volume 19 of Fish Physiology |editor1-last=Block |editor1-first=Barbara A. |editor2-last=Stevens |editor2-first=E. Donald |publisher=Academic Press |location=San Diego, Calif. |year=2001 |chapter=Chapter 1: Systematics of the Tunas and Mackerels (scombridae) |last1=Collette |first1=Bruce B. |last2=Reeb |first2=Carol |last3=Block |first3=Barbara A. |isbn=978-0-12-350443-2 |page=5 |chapter-url=https://books.google.com/books?id=M0ghO6oLXnEC&pg=PA5}}</ref> At present, however, morphology and nuclear phylogeny provide support that ''Gasterochisma'' is sister to all other scombrids, and that both its genus, ''Gasterochisma'', and its subfamily, Gasterochismatinae, remain as monotypic taxa under the family Scombridae.<ref name=Orrell2006/>
The following cladogram shows the most likely evolutionary relationships between the butterfly kingfish and the tunas, mackerels, Spanish mackerels, and bonitos. <div class="thumb" style="margin: 5px; width: 98%;"> <div class="overflowbugx" style="overflow:auto;border=1"> {{cladogram|title=Butterfly kingfish, in the family Scombridae |align=left |caption=Cladogram: With 51 different species in the Scombridae, the butterfly kingfish sits apart from the rest – it is the only scombrid species that does not belong to the subfamily Scombrinae.<ref name=Graham2004>{{cite journal |last=Graham|first=Jeffrey B.|author2=Dickson, Kathryn A.|title=Tuna Comparative Physiology|journal=The Journal of Experimental Biology |year=2004|volume=207|issue=23|pages=4015–4024|doi=10.1242/jeb.01267|pmid=15498947|doi-access=free|bibcode=2004JExpB.207.4015G }}</ref><ref name=Orrell2006>{{cite journal |last1=Orrell |first1=T.M. |last2=Collette |first2=B.B. |last3=Johnson |first3=G.D. |title=Molecular data support separate scombroid and xiphioid clades |journal=Bulletin of Marine Science |year=2006 |volume=79 |issue=3 |pages=505–519 |url=https://www.ingentaconnect.com/content/umrsmas/bullmar/2006/00000079/00000003/art00007 }}</ref> |cladogram={{clade| style=font-size:80%;line-height:80%;width:650px; |label1=family Scombridae |1={{clade |label1=subfamily |1={{clade |label1='''Gasterochismatinae''' |1={{clade |1={{clade |label1=genus'''Gasterochisma''' |1={{clade |1='''''G. melampus'', butterfly kingfish''' }} }} }} }} |label2=subfamily |2={{clade |label1=Scombrinae |1={{clade |1={{clade |1={{clade |1={{clade |1={{clade |label1=tribe Scombrini |1={{clade |1={{clade |1=mackerels (two genera) }} }} }} }} }} |2={{clade |1={{clade |1={{clade |label1=tribe Scomberomorini |1={{clade |1=Spanish mackerels (three genera) }} }} }} |2={{clade |1={{clade |label1=tribe Sardini |1={{clade |1={{clade |1={{clade |1=bonitos (four genera) }} }} }} }} |2={{clade |label1=tribe Thunnini |1={{clade |1={{clade |1={{clade |1=tunas (five genera) }} }} }} }} }} }} }} }} }} }} }} }} </div></div>
==Distribution== The butterfly kingfish has a circumglobal distribution in southern temperate waters.<ref name=IUCN/><ref name=FishBase/> It has caught as far north as Hawaii and seems to be common around Oceania. It prefers waters between {{convert|8|and|15|°C|°F}}.<ref name="WoRMS" />
== Fisheries == While a rare catch, there is a minor commercial market, where they are caught incidentally while targeting other fish, especially through the use of longline fishing. It is of minor importance to recreational Fisheries.<ref name=":0" />{{Clear}} {{Commons}}
==References== {{Reflist}} * Tony Ayling & Geoffrey Cox, ''Collins Guide to the Sea Fishes of New Zealand'', (William Collins Publishers Ltd., Auckland, New Zealand 1982) {{ISBN|0-00-216987-8}}
{{Mackerel}} {{Taxonbar |from=Q934588 |from2=Q17152872 |from3=Q3098869 }}
Category:Scombridae Category:Fish of the Atlantic Ocean Category:Fish of the Indian Ocean Category:Fish of the Pacific Ocean Category:Taxa named by John Richardson (naturalist) Category:Fish described in 1845