Abstract

A new frog species of the genus Mantidactylus is described from the lowland areas of northwestern Madagascar known as the Sambirano Region. Mantidactylus madinika reaches 11–13 mm snout–vent length in males and 15–16 mm in females and is thereby the smallest species in the family Mantellidae. It is included in the subgenus Blommersia based on external morphology but differs from other species of the subgenus by its relative finger length. Several features of the new species (only slightly bifid tongue, absence of vomerine teeth, reduction of maxillary teeth, absence of dark pigment on oocytes) are similar to the states observed in the genus Mantella, which is known to be phylogenetically nested within the paraphyletic Mantidactylus. Miniaturization in the ancestor of Mantella may explain several of the derived character states in this genus.