Editing Carboniferous (section)

===Fish===
Many fish inhabited the Carboniferous seas; predominantly [[Elasmobranch]]s (sharks and their relatives). These included some, like ''[[Psammodus]]'', with crushing pavement-like teeth adapted for grinding the shells of brachiopods, crustaceans, and other marine organisms. Other groups of elasmobranchs, like the [[ctenacanthiformes]] grew to large sizes, with some genera like ''[[Saivodus]]'' reaching around {{convert|6|–|9|m|ft|sp=us}}.<ref>{{Cite journal |last=Engelman |first=Russell K. |date=2023 |title=A Devonian Fish Tale: A New Method of Body Length Estimation Suggests Much Smaller Sizes for Dunkleosteus terrelli (Placodermi: Arthrodira) |journal=Diversity |language=en |volume=15 |issue=3 |pages=318 |doi=10.3390/d15030318 |issn=1424-2818 |doi-access=free |bibcode=2023Diver..15..318E }}</ref> Other fish had piercing teeth, such as the [[Symmoriida]]; some, the [[petalodont]]s, had peculiar cycloid cutting teeth. Most of the other cartilaginous fish were marine, but others like the [[Xenacanthida]], and several genera like ''[[Bandringa]]'' invaded fresh waters of the coal swamps.<ref name="Sallan-2014">{{Cite journal |last1=Sallan |first1=Lauren Cole |last2=Coates |first2=Michael I. |date=January 2014 |title=The long-rostrumed elasmobranch Bandringa Zangerl, 1969, and taphonomy within a Carboniferous shark nursery |url=http://www.tandfonline.com/doi/abs/10.1080/02724634.2013.782875 |journal=Journal of Vertebrate Paleontology |language=en |volume=34 |issue=1 |pages=22–33 |doi=10.1080/02724634.2013.782875 |bibcode=2014JVPal..34...22S |issn=0272-4634 |s2cid=86174861}}</ref> Among the [[Osteichthyes|bony fish]], the [[Palaeonisciformes]] found in coastal waters also appear to have migrated to rivers. [[Sarcopterygii|Sarcopterygia]]n fish were also prominent, and one group, the [[Rhizodont]]s, reached very large size.

Most species of Carboniferous marine fish have been described largely from teeth, fin spines and dermal ossicles,{{sfn|Howe|1911|p=311}} with smaller freshwater fish preserved whole. Freshwater fish were abundant, and include the genera ''[[Ctenodus]]'', ''Uronemus'', ''[[Acanthodes]]'', ''Cheirodus'', and ''[[Gyracanthus]]''. [[Chondrichthyes]] (especially [[Holocephali|holocephalans]] like the [[Stethacanthidae|Stethacanthids]]) underwent a major [[evolutionary radiation]] during the Carboniferous.{{sfn|Martin|2008}} It is believed that this evolutionary radiation occurred because the decline of the [[Placodermi|placoderms]] at the end of the Devonian caused many [[Niche (ecology)|environmental niches]] to become unoccupied and allowed new organisms to evolve and fill these niches.{{sfn|Martin|2008}} As a result of the evolutionary radiation Carboniferous holocephalans assumed a wide variety of bizarre shapes including ''[[Stethacanthus]]'' which possessed a flat brush-like dorsal fin with a patch of [[Dermal denticle|denticles]] on its top.{{sfn|Martin|2008}} ''[[Stethacanthus]]''{{'s}} unusual fin may have been used in mating rituals.{{sfn|Martin|2008}}

Other groups like the [[Eugeneodontida|eugeneodonts]] filled in the niches left by large predatory placoderms. These fish were unique as they only possessed one, at most two, rows of teeth in either their upper or lower jaws in the form of elaborate tooth whorls.<ref name="Lebedev20092">{{cite journal |last1=Lebedev |first1=O.A. |year=2009 |title=A new specimen of ''Helicoprion'' Karpinsky, 1899 from Kazakhstanian Cisurals and a new reconstruction of its tooth whorl position and function |url=https://www.researchgate.net/publication/249440368 |journal=Acta Zoologica |volume=90 |pages=171–182 |doi=10.1111/j.1463-6395.2008.00353.x |issn=0001-7272}}</ref> The first members of the [[helicoprionidae]], a family eugeneodonts that were characterized by the presence of one circular tooth whorl in the lower jaw, appeared during the early Carboniferous.<ref>{{cite journal |author1=Cicimurri, D. J. |author2=Fahrenbach, M. D. |year=2002 |title=Chondrichthyes from the upper part of the Minnelusa Formation (Middle Pennsylvanian: Desmoinesian), Meade County, South Dakota |url=http://www.sdaos.org/wp-content/uploads/pdfs/2002/81-92.pdf |journal=Proceedings of the South Dakota Academy of Science |volume=81 |pages=81–92}}</ref> Perhaps the most bizarre radiation of holocephalans at this time was that of the [[iniopterygiformes]], an order of holocephalans that greatly resembled modern day flying fish that could have also "flown" in the water with their massive, elongated pectoral fins. They were further characterized by their large eye sockets, club-like structures on their tails, and spines on the tips of their fins.

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File:Stethacanthus BW.jpg|''[[Akmonistion]]'' of the [[Holocephali]] order [[Symmoriida]] roamed the oceans of the early Carboniferous.
File:Falcatus.jpg|''[[Falcatus]]'' was a Carboniferous holocephalan, with a high degree of sexual dimorphism.
File:Dracopristis hoffmanorum.png|''[[Dracopristis]]'' was a [[Ctenacanthiformes|Ctenacanthiform]] [[Elasmobranchii|elasmobranch]] from the late Carboniferous of [[New Mexico]].
File:Ornithoprion hertwigi.png|''[[Ornithoprion]]'' was a small-sized [[Eugeneodontida|Eugeneodont]] holocephalan that had an elongated lower jaw.
File:Allenypterus montanus (Restoration) (cropped).jpg|''[[Allenypterus]]'' was a [[Coelacanth]] fish known from the [[Bear Gulch Limestone]] in [[Montana]].
File:†Phanerosteon phonax Carboniferous Bear Gulch.jpg|''[[Phanerosteon]]'' was a [[Osteichthyes|Bony fish]] belonging to the extinct order [[Palaeonisciformes]].
File:Edestus recon.png|''[[Edestus]]'' was a large [[Eugeneodontida|eugeneodontid]] fish that possessed two tooth whorls in its mouth
File:Rhizodus.jpg|''[[Rhizodus]]'' was a large freshwater [[Rhizodontida|Rhizodont]] [[Sarcopterygii|sarcopterygian]] from Europe and North America.
File:Squatinactis NT small.jpg|''[[Squatinactis]]'', a genus of elasmobranch fish from Montana that possessed enlarged pectoral fins similar to modern [[Angelshark|angel sharks]]
File:Bandringa SW.png|''[[Bandringa]]'' is a bizarre elasmobranch fish that lived in [[Illinois]], [[Ohio]] and [[Pennsylvania]] during the [[Moscovian (Carboniferous)|Moscovian]] stage. It superficially resembled a [[paddlefish]], with an elongated upper [[Rostrum (anatomy)|rostrum]].
File:Iniopteryx sp.png|''[[Iniopteryx]]'' was a holocephalan that lived in North America. This fish belonged to a group called the Iniopterygiformes, that possibly lived like [[flying fish]].
File:Strigilodus tollesonae-novataxa 2023-Hodnett Toomey Olson.jpg|Restoration of ''[[Strigilodus tollesonae|Strigilodus]]'', a [[Petalodontiformes|petalodont]] holocephalan from the upper Carboniferous of [[Kentucky]].
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