Macropetalichthys is a genus of placoderm fish, named by Norwood and Owen in 1846; the name "Macropetalichthys" means "armor-plated fish".[1][2] It was assigned to Arthrodira by Woodward (1891); and to Petalichthida by Sepkoski (2002). Several species have been referred to Macropetalichthyes, but the best known is the type species, M. rapheidolabis, from the Jeffersonville Limestone of Indiana, USA, and Columbus Limestone of Ohio, USA.
Range: Early-Middle Devonian (Emsian-Eifelian) of North America and Europe.
Characters: Like primitive Arthrodira. Dorsoventrally compressed; orbits face dorsally; widely splayed pectoral fins, with cornua common; no post-pectoral plates; plates ornamented with linear rows of tubercles.