The standard Late Devonian conodont zonation between the top of the Upper marginifera Zone and the earliest Carboniferous Siphonodella sulcata Zone is revised to replace the former velifer, styriacus, and costatus zonal groups, which were based primarily on genera other than Palmatolepis, and to eliminate a hiatus above the Upper costatus Zone. The changes were enabled by a new phylogenetic model of Palmatolepis, by range extensions that bridge former gaps between the records of some Palmatolepis taxa, and by further taxonomic revisions of some double-rowed Bispathodus taxa. Basing the standard zonation on conodonts of primarily pelagic...