Hidden diversity under stripes: three new species of land flatworms of the genus Paraba (Platyhelminthes: Geoplanidae) from the southern Atlantic forest

Abstract

The dorsal color pattern, together with the morphology of the copulatory apparatus, provide important taxonomic characteristics for the identification of land planarians. In genera such as Paraba, in which most species have a morphologically similar copulatory apparatus and a dorsum with several stripes that vary according to color, width, and arrangement, the existence of pseudocryptic species can lead to a misidentification and underestimation of their diversity. In this work we describe three new species of Paraba which, due to the color pattern, have been mistaken for already described species of the genus. Specimens were collected in different forest formations of the southern Atlantic Forest, Brazil. The new species can be distinguished from each other and from other congeners through the color pattern of the dorsal surface of the body combined with some features of the copulatory apparatus, like the anatomy of the prostatic vesicle and the male atrium. Additionally, we propose an emendation to the diagnosis of Paraba based on characters observed in the three new species and some characteristics occurring in other species of the genus.