An osteological analysis of the three species of the genus Telmatobufo (T. australis, T. bullocki, and T. venustus) was done. That analysis completes the generic definition based mainly on the osteology of T. bullocki and on morphological larval characters. New information on morphometry, chromosomes, reproductive biology, ecology, geographical range. allozymes, and molecular data is provided for each species. A key for the taxonomic determination of adult specimens of Telmatobufo is also presented, An unedited original plate by R.A. Philippi, lost for almost a century, is published for the first timed this plate allowed the restatement of the taxonomical identity of T. venustus. Mahalanobis distance and Rogers' genetic distance were employed to assess the morphological and the genetical similarities among the three Telmatobufo species. Employing mtRNA 12S sequences. in combination with polarized allelic frequencies of structural genes. and morphological (external and osteological) characters, a hypothesis on the phylogenetic relationships of the Telmatobufo species is proposed, worked on principles of maximum parsimony and maximum likelihood. Finally, a reconstruction of the evolutionary history and speciation process of this group of endemic frogs of the temperate central southern Chilean forests is proposed.