A New Species of Vietnamophryne with an Extended Description of Vietnamophryne orlovi

We describe Vietnamophryne cuongi sp. nov., a new species of microhylid frog from northern Vietnam, based on morphological and molecular differences. Although superficially similar to remaining Vietnamophryne members, the new species differs by a number of diagnostic morphological characters, such as body size, habitus, head dimensions, finger and toe morphology, skin texture, as well as colour pattern. Phylogenetic analyses based on a fragment of the mitochondrial 16S gene place the new species to be sister to V. orlovi, from which it differed by 2.4% genetic divergence. We also describe the first female known of V. orlovi, collected in the forest of Phia Oac-Phia Den National Park, Cao Bang Province. The latter species, for which we provide an extended description herein, was recently described based on the single male type specimen only from the same site in northern Vietnam. Vietnamophryne cuongi sp. nov. is only known from three specimens, two adult females and a juvenile, from the evergreen tropical forest of Ba Vi National Park, Hanoi. As such, it is likely to be at high risk of habitat loss. Considering its high ecological specialization and the small known distribution range of the new species, we propose Endangered as IUCN Red List status.