Revision of the Subgenus Ochthomantis Frogs from Madagascar (Amphibia: Mantellidae) with the Description of Four Species and Resurrection of Mantidactylus catalai and M. poissoni

The subgenus Ochthomantis is an obligate forest and stream-dwelling group of Mantellid frogs, endemic to Madagascar, with six species currently recognized. However, this group suffers from ongoing taxonomic confusion due to low numbers of examined specimens, and failure to con-sider morphological variation from development and sexual dimorphism. Here we examined the morphology of 637 adult sexed specimens, collected by us in the field, and from other Mu-seum collections. We also sequenced the 16S mtDNA gene for each lineage, to determine con-gruence between morphological and molecular data sets, and to help delimit species. Our results demonstrate that the subgenus Ochthomantis includes 11 valid species: five already recognized; M. catalai and M. poissoni that we resurrect from synonymy, and four new species which we de-scribe here. Because Mantidactylus majori groups with other Mantidactylus, we do not consider it a member of the subgenus Ochthomantis. All species have restricted distributions and elevational ranges in the humid forests of Madagascar. This study demonstrates the utility of studying cryp-tic species using both diagnostic morphological characters and molecular data. It is hoped that discovery of this new cryptic biodiversity will initiate conservation activities for those species with the most restricted distributions.