Decorataria magnilabiata (Molin, 1860) n. comb. is proposed for Dispharagus magnilabiatus Molin, 1860 [= Acuaria (Cheilospirura) magnilabiata (Molin, 1860) Railliet, Henry & Sisoff, 1912; Cheilospirura magnilabiata (Molin, 1860) Stiles & Hassall, 1920; Dispharynx magnilabiata (Molin, 1860) Gendre, 1920] (Nematoda, Spirurida, Acuariidae), a parasite of the roseate spoonbill Platalea ajaja L. (Ciconiiformes, Threskiornithidae) known from Brazil, France (bird in captivity), Argentina and Cuba. The species is redescribed and illustrated on the basis of the type-series (from Brazil) in the Helminthological Collection of the Naturhistorisches Museum, Vienna. Syncuaria diacantha Petter, 1961 [= Decorataria diacantha (P.) Skryabin, Sobolev & Ivashkin, 1965], originally described from Platalea ajaja in France (bird in captivity), is recognised as a junior synonym of Decorataria magnilabiata (new synonymy).