Cosmoptychius

{{Short description|Extinct genus of ray-finned fishes}}

{{Speciesbox

| fossil_range = {{fossilrange|340.2|330.9|Viséan}}

| image =

| image_caption =

| taxon = Cosmoptychius striatus

| authority = (Agassiz, 1835)

| parent_authority = Traquair, 1877

| grandparent_authority = Gardiner, 1963

| synonyms =

• †Amblypterus striatus Agassiz, 1835
• †Cosmoptygius Traquair, 1877 (misspelling)

}}

Cosmoptychius is an extinct genus of freshwater and estuarine ray-finned fish that lived during the Mississippian epoch.{{cite journal|last=Sepkoski |first=Jack |title=A compendium of fossil marine animal genera |journal=Bulletins of American Paleontology |volume=364 |page=560 |year=2002 |url=http://strata.ummp.lsa.umich.edu/jack/showgenera.php?taxon=611&rank=class |accessdate=2009-04-24 |url-status=dead |archiveurl=https://web.archive.org/web/20090220223520/http://strata.ummp.lsa.umich.edu/jack/showgenera.php?taxon=611&rank=class |archivedate=2009-02-20 }}{{Cite journal |last=Coates |first=M. I. |date=1993 |title=Actinopterygian and acanthodian fishes from the Viséan of East Kirkton, West Lothian, Scotland |url=https://www.cambridge.org/core/journals/earth-and-environmental-science-transactions-of-royal-society-of-edinburgh/article/abs/actinopterygian-and-acanthodian-fishes-from-the-visean-of-east-kirkton-west-lothian-scotland/BDD9C6A121819E224F9C5FDA5F694650 |journal=Earth and Environmental Science Transactions of the Royal Society of Edinburgh |language=en |volume=84 |issue=3–4 |pages=317–327 |doi=10.1017/S0263593300006131 |bibcode=1993EESTR..84..317C |issn=1755-6929|url-access=subscription }} It contains a single species, C. striatus from the Visean of Scotland.{{Cite web |title=PBDB Taxon |url=https://paleobiodb.org/classic/basicTaxonInfo?taxon_no=469984 |access-date=2024-06-18 |website=paleobiodb.org}} It has a wide stratigraphic range in the Wardie Shale, with many specimens known.{{Cite journal |last=Gardiner |first=B. G. |date=1985 |title=Actinopterygian fish from the Dinantian of Foulden, Berwickshire, Scotland |url=https://www.cambridge.org/core/journals/earth-and-environmental-science-transactions-of-royal-society-of-edinburgh/article/abs/actinopterygian-fish-from-the-dinantian-of-foulden-berwickshire-scotland/AB89D7115FB9B9683D7277D95B2F3C7B |journal=Earth and Environmental Science Transactions of the Royal Society of Edinburgh |language=en |volume=76 |issue=1 |pages=61–66 |doi=10.1017/S0263593300010312 |issn=1473-7116|url-access=subscription }}{{Cite journal |last1=Dornburg |first1=Alex |last2=Townsend |first2=Jeffrey P. |last3=Friedman |first3=Matt |last4=Near |first4=Thomas J. |date=2014-08-08 |title=Phylogenetic informativeness reconciles ray-finned fish molecular divergence times |journal=BMC Evolutionary Biology |language=en |volume=14 |issue=1 |pages=169 |doi=10.1186/s12862-014-0169-0 |issn=1471-2148 |pmc=4236503 |pmid=25103329 |doi-access=free|bibcode=2014BMCEE..14..169D }}

Initially classified as either a palaeonisciform (a now-paraphyletic group of basal actinopterygians){{Cite book |last=Nelson |first=Joseph S. |url=http://dx.doi.org/10.1002/9781119174844 |title=Fishes of the World |last2=Grande |first2=Terry C. |last3=Wilson |first3=Mark V. H. |date=2016-02-22 |publisher=Wiley |isbn=978-1-118-34233-6}} or the earliest stem-group neopterygian, it is now generally considered a stem-group actinopteran.{{Cite journal |last1=Xu |first1=Guang-Hui |last2=Gao |first2=Ke-Qin |last3=Finarelli |first3=John A. |date=2014-06-07 |title=A revision of the Middle Triassic scanilepiform fish Fukangichthys longidorsalis from Xinjiang, China, with comments on the phylogeny of the Actinopteri |url=http://www.tandfonline.com/doi/abs/10.1080/02724634.2014.837053 |journal=Journal of Vertebrate Paleontology |language=en |volume=34 |issue=4 |pages=747–759 |doi=10.1080/02724634.2014.837053 |bibcode=2014JVPal..34..747X |issn=0272-4634|url-access=subscription }}