Land flatworms show high endemism due to their restricted mobility. In southern Brazil, land flatworm communities have been found mainly in areas of ombrophilous forests. Thus, this study documents land planarian species composition in remnants of deciduous seasonal forest in the northeast region of southern Brazil. Direct, diurnal samplings reveal the occurrence of 26 species of land flatworms, of which one belongs to the subfamily Rhynchodeminae and the others to the subfamily Geoplaninae.

The genus Obama Carbayo, Álvarez-Presas, Olivares, Marques, Froehlich & Riutort, 2013 currently comprises 41 species, most of them from Brazilian rainforests. This study describes three new species, viz. Obama autumna sp. nov., Obama leticiae sp. nov. and Obama aureolineata sp. nov., from remnants of Mixed Ombrophilous Forest in southern Brazil, based on an integrative approach and analyses their relationships within the genus. Obama autumna and O. aureolineata show distinctive colour patterns, contrasting yellow and black, which is unusual in species of the genus. The three species can be easily distinguished from their congeners by their external features and a combination of anatomical characteristics, such as the pharyngeal shape, shape and arrangement of the prostatic vesicle and anatomy of the penis papilla. The morphological hypotheses are corroborated by three species delimitation methods (ABGD, PTP and GMYC) and by phylogenetic analysis of the cytochrome c oxidase subunit I gene using maximum likelihood estimation and Bayesian inference. Furthermore, our phylogenetic analyses point out that Obama may be subdivided into three main clades, containing a variable number of well supported groups, the relationships of which remain unresolved. Obama autumna belongs to a distinct clade in relation to O. aureolineata and O. leticiae. Obama aureolineata belongs to one of the well supported groups, having a close relationship with O. apeva. Obama autumna may be more closely related to O. anthropophila and O. decidualis and O. leticiae to O. braunsi. However, the low nodal support does not allow the phylogenetic relationships of these species to be clearly established. We discuss morphological knowledge gaps in Obama, as well as issues regarding analyses based on molecular markers, which should be addressed to clarify relationships within the genus. urn:lsid:zoobank.org:pub:9EE7316D-F0BE-49EC-BBFD-5687952D6592

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