A brief abridgement of the taxonomic history of the Atelopodidae is presented, and it is concluded that this group must be included in the Bufonidae, confirming the criteria of recent authors. OSORNOPHRYNE is proposed as a new genus, characterized mainly by external, osteological and myological features, with O. percrassa, sp, nov. (loc. typ.: Paramo de Herveo, Tolima, Colombia) as type species, and O. bufoniformis, comb. nov. (= Atelopus bufoniformis PERACCA,1904) from the Andes of southern Colombia and northern Ecuador, as a referred species. The functional and adaptative significance of the main characters is discussed in detail. It is concluded that the genus presents several primitive characters of remarkable interest, i.a. the inguinal amplexus, previously unknown in the family, which strengthens the thesis that the Bufonidae are derived from the Leptodactylidae, as well as several other highly especialized skeletal and myological features (i. a . a total number of 6 presacral vertebrae, only shared by two other recent anuran genera: Hymenochirus [Pipidae] and Oreophrynella [Bufonidae]). It is concluded also that Osornophryne, although shows several remarkable phenetic similitudes with Oreophrynella (monotypic endemic genus of the Mount Roraima, Bolivar, Venezuela), such similitudes are due to an extraordinary instance of evolutionary convergence. Osornophryne is regarded as a genus probably derived from the same encestral phyletic line that gives origin to Atelopus, invading the high Andean paramos, specializing and acquiring by adaptative paralellism several resemblances, such as the bufonoid aspect, with the high Andean species of Atelopus.