Focus on the details: morphological evidence supports new cryptic land flatworm (Platyhelminthes) species revealed with molecules

We found numerous dull brown land planarians of the subfamily Geoplaninae within native rainforests and in nearby man-disturbed habitats in Southeastern and South Brazil. Their external and internal morphology are similar to those of Obama ladislavii (Von Graff, 1899), with the exception of the luminous green dorsum of this species, from which a brownish-green variation is also known. Since morphological features commonly used to delimit geoplaninid species failed to distinguish them, we used coalescent and Bayesian-based molecular methods (GMYC, BPP). These methods indicated that we were actually dealing with three species, the greenish O. ladislavii, and two brownish, cryptic species. A meticulous morphological study of the specimens, including type material of O. ladislavii, allowed us to ascertain diagnostic features for each of the species, for which we also propose a molecular diagnosis. This integrative taxonomic study demonstrates the utility of molecular tools to weigh minor morphological features and thus to reveal otherwise cryptic species.