Five new pseudocryptic land planarian species of Cratera (Platyhelminthes: Tricladida) unveiled through integrative taxonomy.

BACKGROUND: Cratera is a genus of land planarians endemic to the Brazilian Atlantic forest. The species of this genus are distinguished from each other by a series of external and internal characters, nonetheless they represent a challenging taxonomic issue due to the extreme alikeness of the species analysed in the present work. To resolve these difficulties, we have performed morphological analyses and used three nuclear markers (ribosomal 18S and 28S, Elongation Factor, a new anonymous marker named Tnuc813) and two mitochondrial fragments (Cytochrome c oxidase subunit I gene, and a fragment encompasing NADH deshydrogenase subunit 4 gene, trnF and the beginning of the Cytochrome c oxidase I gene) in an integrative taxonomic study. METHODS: To unveil cryptic species, we applied a molecular species delimitation approach based on molecular discovery methods, followed by a validation method. The putative species so delimited were then validated on the basis of diagnostic morphological features. RESULTS: We discovered and described four new species, namely Cratera assu, C. tui, C. boja, and C. imbiri. A fifth new species, C. paraitinga was not highly supported by molecular evidence, but was described because its morphological attributes are unique. Our study documents for the genus Cratera the presence of a number of highly similar species, a situation that is present also in other genera of land planarians. The high number of poorly differentiated and presumably recent speciation events might be explained by the recent geological history of the area.

A new species of the land planarian Issoca sheds light on the polyphyletic status of the genus (Platyhelminthes, Tricladida, Geoplaninae).

A new species of the genus Issoca (Platyhelminthes, Tricladida, Geoplaninae) is described. Issoca assanga sp. n. presents the diagnostic features of the genus, with the exception of the relative position of the subneural parenchymal muscle layer with the cephalic retractor muscle, which are overlapped in the type species of the genus but are intersected in the new species. Rather than a polymorphic character, the relative position of these muscle layers might reflect the polyphyletic status of the genus.