Two new graptolite species are described. These species, Maeandrograptus bolivianus n.sp. and Gymnograptus floweri n.sp., were probably contemporaneous with congeners from the Didymograptus hirundo Zone (Lower Ordovician) of Sweden and the lower half of the Glyptograptus teretiusculus Zone (Middle Ordovician) of Baltoscandia, respectively. This is the first report of these genera in the Western Hemisphere. The assignment of a new species to Maeandrograptus necessitated revision of that genus. As revised, it consists of M. schmalenseei Moberg, Didymograptus mobergi Toernquist, and M. bolivianus n.sp. Cymatograptus undulatus is a possible ancestor for this group of species, and an assignment of Maeandrograptus to the Sinograptidae is favoured.--Modified journal abstract.