Prosomyleus

{{Short description|Species of fish}}

{{Speciesbox

| name =

| image = Coumarou.jpg

| image_caption =

| parent_authority = Géry, 1972

| display_parents = 2

| taxon = Prosomyleus rhomboidalis

| authority = (G. Cuvier, 1818)

| synonyms = * Myleus rhomboidalis

}}

Prosomyleus rhomboidalis is a medium to large omnivorous fish of the family Serrasalmidae from South America, where it is found in the Amazon River basin, as well as the north and the eastern Guiana Shield rivers. It is the only species in the genus Prosomyleus. It can grow to a length of {{convert|40.7|cm|in|abbr=on}}.{{FishBase |genus= Myloplus|species= rhomboidalis| month = February | year = 2015}} It was formerly placed in the genus Myleus, of which it was thought to be the only member of its own subgenus, Prosomyleus. It was upgraded to being a distinct genus in 2021.{{Cof genus|genus=Prosomyleus|access-date=10 May 2025}}{{Cite journal |last=Kolmann |first=M A |last2=Hughes |first2=L C |last3=Hernandez |first3=L P |last4=Arcila |first4=D |last5=Betancur-R |first5=R |last6=Sabaj |first6=M H |last7=López-Fernández |first7=H |last8=Ortí |first8=G |date=2021-05-01 |title=Phylogenomics of Piranhas and Pacus (Serrasalmidae) Uncovers How Dietary Convergence and Parallelism Obfuscate Traditional Morphological Taxonomy |url=https://academic.oup.com/sysbio/article/70/3/576/5891674 |journal=Systematic Biology |volume=70 |issue=3 |pages=576–592 |doi=10.1093/sysbio/syaa065 |issn=1063-5157}}