Bluefieldius

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

{{Speciesbox

| fossil_range = {{fossilrange|323.5|326|Late Mississippian}}

| image = Bluefieldius fig-3-full-b.png

| image_caption = Holotype specimen

| taxon = Bluefieldius mercerensis

| authority = Mickle, 2018

| parent_authority = Mickle, 2018

}}

Bluefieldius is an extinct genus of marine ray-finned fish that lived during the Late Mississippian (Early Carboniferous) epoch in what is now West Virginia, United States.{{Cite web |title=PBDB |url=https://paleobiodb.org/classic/basicTaxonInfo?taxon_no=479315 |access-date=2024-03-19 |website=paleobiodb.org}} It is known from a single fossil collected from the late Serpukhovian or early Viséan Bluefield Formation.{{cite journal |last=Mickle |first=Kathryn E. |year=2018 |title=A new lower actinopterygian fish from the Upper Mississippian Bluefield Formation of West Virginia, USA |journal=PeerJ |volume=6 |pages=e5533 |doi=10.7717/peerj.5533 |pmid=30186696 |pmc=6119456 |doi-access=free}} The type and only species (monotypy) is Bluefieldius mercerensis.

It has a "palaeoniscoid" body plan, although as that order is thought to be paraphyletic, it was described as an indeterminate actinopterygian.