Akmonistion

{{Short description|Extinct genus of cartilaginous fishes}}

{{Speciesbox

| fossil_range = {{fossil range|Serpukhovian}}

| image = Akmonistion zangerli Coates & Sequeira.jpg

| image_caption = Holotype fossil

| image2 = Akmonistion zangerli.png

| image2_caption = Reconstruction

| genus = Akmonistion

| species = zangerli

| authority = Coates & Sequeira, 2001

}}

Akmonistion is an extinct genus of cartilaginous fish that lived in the Early Carboniferous. The genus contains a single species, A. zangerli, discovered by Stan Wood in 1982.{{cite journal |last1=Wood |first1=S.P. |title=New basal Namurian (Upper Carboniferous) fishes and crustaceans found near Glasgow |journal=Nature |date=1982 |volume=297 |pages=574-577}} It is distinguished by an unusual enlarged formation of the dorsal fin, called a "spine-brush complex", of unknown function. This is also found in the better known genus Stethacanthus. Remains have only been found near Bearsden in Scotland.{{cite journal|last1=Coates|first1=M.I.|last2=Sequeira|first2=S.E.K.|year=2001|title=A new stethacanthid chondrichthyan from the lower Carboniferous of Bearsden, Scotland|journal=Journal of Vertebrate Paleontology|volume=21|issue=3|pages=438–459|url=https://pondside.uchicago.edu/oba/faculty/coates/CoatesSequeira2001Akmonist.pdf|doi=10.1671/0272-4634(2001)021[0438:anscft]2.0.co;2}}{{cite web|url=https://paleobiodb.org/classic/checkTaxonInfo?taxon_no=248785&is_real_user=1|title= Akmonistion zangerli|website=Palaeobiology Database}} The genus name is derived from the Ancient Greek “akmon” (“anvil”) + “istion” (“sail”) referring to the appearance of its first dorsal fin. It reached {{cvt|62|cm}} in length.