The purpose of this paper was to study specimens of the genus Rodentolepis isolated from eight species of Sigmodontinae rodents (Rodentia: Cricetidae) from six provinces in the Cuenca del Plata, Argentina, based on morphological, morphometric and molecular characteristics (ITS1 rDNA and cox1 mtDNA). The genetic distances among studied specimens and other Hymenolepididae from rodents available in the GenBank were analyzed and phylogenetic inferences were provided. A total of 955 specimens of Sigmodontinae rodents were examined from seven localities of six provinces in the Cuenca del Plata region in Argentina. Tapeworms were removed from the rodents' small intestines. Conventional studies were used for the morphological and molecular analysis. Specimens of R. microstoma were identified. An amended diagnosis and detailed morphological description of this species is provided. The molecular analyses showed that the specimens studied form the same clade as that of R. microstoma previously studied from other hosts and regions. The genetic polymorphisms of R. microstoma observed corresponded to different groups of species hosts and regions. Moreover, eight species of sigmodontine rodents and 33 localities from the Cuenca del Plata region in Argentina constitute new host and geographical records. This study shows the importance of using integrative taxonomic approaches that combine morphological and molecular characters to understand biological diversity. Moreover, the discovery of R. microstoma in humans suggests the importance of further studies on this zoonotic cestode. This study provides important data on the taxonomy and distribution of R. microstoma to advance knowledge of the transmission dynamics of this parasite.
Keywords: Argentina; Hymenolepididae; Rodentolepis; Rodents; Taxonomy.
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