Leiognathidae

{{Short description|Family of ray-finned fishes}} {{Automatic taxobox | fossil_range = {{fossilrange|56|0}} Eocene to Present<ref>{{cite journal|last=Sepkoski |first=J. |title=A compendium of fossil marine animal genera |journal=Bulletins of American Paleontology |volume=364 |page=560 |date=2002 |url=http://strata.ummp.lsa.umich.edu/jack/showgenera.php?taxon=611&rank=class |url-status=dead |archive-url=https://web.archive.org/web/20110723131237/http://strata.ummp.lsa.umich.edu/jack/showgenera.php?taxon=611&rank=class |archive-date=2011-07-23 }}</ref> | image = Lespl_u0.gif | image_caption = ''Eubleekeria splendens'' | taxon = Leiognathidae | authority = T. N. Gill, 1893<ref name = VDLEF>{{cite journal | author1 = Richard van der Laan | author2 = William N. Eschmeyer | author3 = Ronald Fricke | name-list-style = amp |year=2014 | title = Family-group names of Recent fishes | url = https://biotaxa.org/Zootaxa/article/view/zootaxa.3882.1.1/10480 | journal = Zootaxa | volume = 3882 | issue =2 | pages = 001–230| doi = 10.11646/zootaxa.3882.1.1 | pmid = 25543675 | doi-access = free }}</ref> | subdivision_ranks = Genera | subdivision = See text | type_species = ''Leiognathus argenteus'' | type_species_authority = Lacépède, 1802<ref name = CofF>{{Cof family | family = Leiognathidae | access-date = 18 November 2020}}</ref> }}

'''Leiognathidae''', the '''ponyfishes''', '''slipmouths''' or '''slimys / slimies''', are a small family of fishes in the order Acanthuriformes. They inhabit marine and brackish waters in the Indo-Pacific. They can be used in the preparation of ''bagoong''.

==Characteristics== Ponyfishes are small and laterally compressed in shape, with silvery colouration. They are distinguished by highly extensible mouths, and the presence of a mechanism for locking the spines in the dorsal and anal fins. They also possess a highly integrated light organ in their throats that houses symbiotic bioluminescent bacteria that project light through the animal's underside.<ref name=EoF>{{cite book |editor=Paxton, J.R. |editor2=Eschmeyer, W.N.|author1=Johnson, G.D. |author2=Gill, A.C. |name-list-style=amp |year=1998|title=Encyclopedia of Fishes|publisher= Academic Press|location=San Diego|isbn= 978-0-12-547665-2|page= 186}}</ref><ref name=":0">{{Cite journal|last1=Haneda|first1=Y.|last2=Tsuji|first2=F.I.|year=1976|title=Luminescent systems of pony fishes|journal=Journal of Morphology|volume=150|issue=2|pages=539–552|doi=10.1002/jmor.1976.150.2.539|s2cid=91711575 }}</ref><ref name=":1">{{Cite journal|last1=McFall-Ngai|first1=M.J.|last2=Dunlap|first2=P.V.|date=1984|title=External and internal sexual dimorphism in leiognathid fishes: Morphological evidence for sex-specific bioluminescent signaling|journal=Journal of Morphology|language=en|volume=182|issue=1|pages=71–83|doi=10.1002/jmor.1051820105|pmid=6492170|s2cid=23956409 |issn=1097-4687}}</ref> Typically, the harbored bacterium is only ''Photobacterium leiognathi'', but in the two ponyfish species ''Photopectoralis panayensis'' and ''Photopectoralis bindus'', ''Photobacterium mandapamensis'' is also present.<ref>{{Cite journal|last1=Kaeding|first1=A.J.|last2=Ast|first2=J.C.|last3=Pearce|first3=M.M.|last4=Urbanczyk|first4=H.|last5=Kimura|first5=S.|last6=Endo|first6=H.|last7=Nakamura|first7=M.|last8=Dunlap|first8=P.V.|date=2007|title=Phylogenetic Diversity and Cosymbiosis in the Bioluminescent Symbioses of "Photobacterium mandapamensis"|journal=Applied and Environmental Microbiology|language=en|volume=73|issue=10|pages=3173–3182|doi=10.1128/AEM.02212-06|issn=0099-2240|pmc=1907103|pmid=17369329|bibcode=2007ApEnM..73.3173K }}</ref> Two of the most widely studied uses for luminescence in ponyfish are camouflage by ventral counterillumination<ref>{{Cite journal|last=Hastings|first=J.W.|date=1971|title=Light to Hide by: Ventral Luminescence to Camouflage the Silhouette|journal=Science|language=en|volume=173|issue=4001|pages=1016–1017|doi=10.1126/science.173.4001.1016|issn=0036-8075|pmid=17796582|bibcode=1971Sci...173.1016W |s2cid=5680392 }}</ref><ref>{{Cite journal|last1=McFall-Ngai|first1=M.J.|last2=Morin|first2=J.G.|date=1991|title=Camouflage by Disruptive Illumination in Leiognathids, a Family of Shallow-Water, Bioluminescent Fishes|url=http://jeb.biologists.org/content/156/1/119|journal=Journal of Experimental Biology|language=en|volume=156|issue=1|pages=119–137|doi=10.1242/jeb.156.1.119 |issn=0022-0949|url-access=subscription}}</ref> and species-specific sexual dimorphism.<ref name=":0" /><ref name=":1" /><ref name=":2">{{Cite journal|last1=Sparks|first1=J.S.|last2=Dunlap|first2=P.V.|last3=Smith|first3=W.L.|date=2005|title=Evolution and diversification of a sexually dimorphic luminescent system in ponyfishes (Teleostei: Leiognathidae), including diagnoses for two new genera|journal=Cladistics|language=en|volume=21|issue=4|pages=305–327|doi=10.1111/j.1096-0031.2005.00067.x|pmid=34892969 |issn=1096-0031|hdl=2027.42/72092|s2cid=53063530 |url=https://deepblue.lib.umich.edu/bitstream/2027.42/72092/1/j.1096-0031.2005.00067.x.pdf|hdl-access=free}}</ref><ref name=":3">{{Cite journal|last1=Chakrabarty|first1=P.|last2=Davis|first2=M.P.|last3=Smith|first3=W.L.|last4=Berquist|first4=R.|last5=Gledhill|first5=K.M.|last6=Frank|first6=L.R.|last7=Sparks|first7=J.S.|date=2011|title=Evolution of the light organ system in ponyfishes (Teleostei: Leiognathidae)|journal=Journal of Morphology|language=en|volume=272|issue=6|pages=704–721|doi=10.1002/jmor.10941|pmid=21433053|s2cid=9331522 |issn=1097-4687}}</ref> The light organ systems of ponyfishes are highly variable across species and often between sexes.<ref name=":2" /><ref name=":3" />

==Taxonomy== Leiognathidae was classified within the suborder Percoidei by the 5th edition of ''Fishes of the World'', but it was placed in an unnamed clade outside the superfamily Percoidea. This clade contains 7 families which appeared to have some relationship to Acanthuroidei, Monodactylidae, and Priacanthidae.<ref name = Nelson5>{{cite book |title=Fishes of the World |edition=5th |author1=J. S. Nelson |author2=T. C. Grande |author3=M. V. H. Wilson |year=2016 |pages=453 |publisher=Wiley |isbn=978-1-118-34233-6 |url=https://sites.google.com/site/fotw5th/ |archive-date=2019-04-08 |access-date=2020-11-17 |archive-url=https://web.archive.org/web/20190408194051/https://sites.google.com/site/fotw5th/ |url-status=dead }}</ref> Betancur-Rodriguez et al. (2017) placed the family in the order Chaetodontiformes alongside the family Chaetodontidae.<ref name="Betancur-Rodriguez-4">{{cite journal | author1 = R. Betancur-Rodriguez | author2 = E. Wiley | author3 = N. Bailly | author4 = A. Acero | author5 = M. Miya | author6 = G. Lecointre | author7 = G. Ortí | doi = 10.1186/s12862-017-0958-3 | title = Phylogenetic Classification of Bony Fishes – Version 4 | year = 2017 | journal = BMC Evolutionary Biology | volume = 17 | issue = 162| page = 162 | pmid = 28683774 | pmc = 5501477 | doi-access = free | bibcode = 2017BMCEE..17..162B }}</ref> More recent classifications place Leiognathidae and the other aforementioned families in the order Acanthuriformes.<ref name="ECoF">{{cite web |title=Eschmeyer's Catalog of Fishes Classification - California Academy of Sciences |url=https://www.calacademy.org/scientists/catalog-of-fishes-classification/ |access-date=10 February 2026 |language=en}}</ref><ref name="Near2024">{{cite journal |last1=Near |first1=T. J. |last2=Thacker |first2=C. E. |title=Phylogenetic Classification of Living and Fossil Ray-Finned Fishes (Actinopterygii) |journal=Bulletin of the Peabody Museum of Natural History |date=2024 |volume=65 |issue=1 |doi=10.3374/014.065.0101}}</ref>

==Genera== The following genera are classified within the Leiognathidae, divided between two subfamilies based on ''Eschmeyer's Catalog of Fishes'':<ref name=FB>{{FishBase family | family = Leiognathidae| month = February | year = 2015}}</ref><ref name = CofF/><ref name="CofF2">{{Cof family|family=Leiognathidae|access-date=3 September 2025}}</ref>

* Subfamily '''Leiognathinae''' Gill, 1893 ** ''Aurigequula'' Fowler, 1918 ** ''Leiognathus'' Lacepède, 1802 * Subfamily '''Gazzinae''' Chakrabarty & Sparks, 2015 ** ''Deveximentum'' Fowler, 1904 (previously as replacement name ''Secutor '' Gistel, 1848) ** ''Equulites'' Fowler, 1904 ** ''Eubleekeria'' Fowler, 1904 ** ''Gazza'' Rüppell, 1835 ** ''Karalla'' Chakrabarty & Sparks, 2008 ** ''Nuchequula'' Whitley, 1932 ** ''Photolateralis'' Sparks & Chakrabarty, 2015<ref name="Sparks2015">{{cite journal | last1 = Sparks | first1 = J.S. | last2 = Chakrabarty | first2 = P. | year = 2015 | title = Description of a new genus of ponyfishes (Teleostei: Leiognathidae), with a review of the current generic-level composition of the family | journal = Zootaxa | volume = 3947 | issue = 2| pages = 181–190 | doi=10.11646/zootaxa.3947.2.2| pmid = 25947728 }}</ref> ** ''Photopectoralis'' Sparks, Dunlap & Smith, 2005 The following fossil genera are also known:

* †''Eoleiognathus'' Bannikov, 2014 (Early Eocene of Italy)<ref>{{Cite journal |last=Bannikov |first=Alexandre F. |date=2014 |title=The new genus ''Eoleiognathus'' for the percoid fish ''Pygaeus dorsalis'' Agassiz from the Eocene of Bolca in northern Italy, a putative ponyfish (Perciformes, Leoignathidae) |url=https://www.researchgate.net/profile/A-Bannikov/publication/265518807_The_new_genus_Eoleiognathus_for_the_percoid_fish_Pygaeus_dorsalis_Agassiz_from_the_Eocene_of_Bolca_in_northern_Italy_a_putative_ponyfish_Perciformes_Leoignathidae/links/5411682d0cf264cee28b2b10/The-new-genus-Eoleiognathus-for-the-percoid-fish-Pygaeus-dorsalis-Agassiz-from-the-Eocene-of-Bolca-in-northern-Italy-a-putative-ponyfish-Perciformes-Leoignathidae.pdf |journal=Studi e ricerche sui giacimenti terziari di Bolca, XV - Miscellanea paleontologica |issue=12 |pages=35 - 42}}</ref> * †''Euleiognathus'' Yabumoto & Uyeno, 2011 (Middle Miocene of Japan)<ref>{{Cite journal |last=Yabumoto |first=Yoshitaka |last2=Uyeno |first2=Teruya |date=2011-01-01 |title=Euleiognathus, a new genus proposed for the Miocene ponyfish, Leiognathus tottori Yabumoto and Uyeno 1994 (Perciformes: Leiognathidae) from Japan |url=https://doi.org/10.1007/s10228-010-0182-2 |journal=Ichthyological Research |language=en |volume=58 |issue=1 |pages=19–23 |doi=10.1007/s10228-010-0182-2 |issn=1616-3915|url-access=subscription }}</ref> * †''Leiognathoides'' Bannikov, 2001 (Early Oligocene to Early Miocene of Switzerland, Azerbaijan and North Caucasus, Russia)<ref>{{Cite journal |last=Bannikov |first=A. F. |date=2000 |title=A New Fossil Genus of Ponyfish (Perciformes, Leiognathidae) |url=https://www.researchgate.net/profile/A-Bannikov/publication/266782723_A_new_fossil_genus_of_ponyfish_Perciformes_Leiognathidae/links/546082520cf295b56161f07a/A-new-fossil-genus-of-ponyfish-Perciformes-Leiognathidae.pdf |journal=Journal of Ichthyology |volume=41 |issue=1 |pages=112-114}}</ref>

==References== {{Reflist}}

Category:Leiognathidae Category:Bioluminescent fish Category:Acanthuriformes families Category:Extant Eocene first appearances