A new species of mantellid frog of the genus Guibemantis from south-eastern Madagascar

We describe a new species of arboreal mantellid frog of the genus Guibemantis (classified in the subgenus Guibemantis) from Madagascar. The new species, Guibemantis sioka sp. nov., is morphologically similar to G. depressiceps but differs by a high uncorrected genetic distance greater than 6% in the mitochondrial 16S rRNA gene from all other related species, and by a conspicuous dark-light marbling of the flanks, relatively large hands, and the structure of its advertisement calls from its closest relatives.

Single individuals of the new species have been found at each of three high-elevation sites (1210–1650 m a.s.l.) in the Southern Central East and South East of Madagascar (Ranomafana National Park, Ivohiboro Reserve, and Andohahela National Park). If this apparent rarity was confirmed by future studies, it would stand in stark contrast to other Guibemantis which are often observed in large breeding aggregations.